Synchrony General Information Manual

Transcription

Synchrony
General Information Manual
MC17231
September 1996
TimePlex Group
Worldwide Headquarters
400 Chestnut Ridge Road
Woodcliff Lake, NJ 07675
USA
(888) 777-0929 • (201) 391-1111
Americas Division
400 Chestnut Ridge Road
Woodcliff Lake, NJ 07675
USA
(888) 777-0929 • (201) 391-1111
CANADA
30 Fulton Way
Richmond Hill, ON
Canada L4B-1E6
(905) 886-6100
Americas Customer Support
16255 Bay Vista Drive
Clearwater, FL 34620
USA
(813) 530-9475
Timeplex Federal Systems, Inc.
Far East Division
12150 Monument Drive
Suite 750
Fairfax, VA 22033
USA
(703) 385-3366
30th Floor, Windsor House
311 Gloucester Road
Causeway Bay
Hong Kong
(852) 2830 9889
Europe/Middle East/Africa
Division
Australia/New Zealand
Division
Langley Business Centre
Station Road, Langley
Slough, Berkshire, SL3 8DT
United Kingdom
(44) 0 1753 601000
Level 21
1 York Street
Sydney, NSW 2000
Australia
(612) 9 247 1422
EUROPE/AFRICA DISTRIBUTORS
10 Rue de Genéve, Bte 17
B-1140 Brussels
Belgium
(32) 2 745.02.30
FRANCE
39 Avenue des Trois Peuples
F-78180 Montigny-le-Bretonneux
France
(33.1) 30.64.81.00
GERMANY
Edisonstrasse 11-13
D-60388 Frankfurt
Germany
(49) 610-973-8505
4/98
NO WARRANTIES ARE EXTENDED BY THIS DOCUMENT. The technical information
in this document is proprietary to Timeplex, Inc. and the recipient has a personal, nonexclusive and non-transferable license to use this information solely with the use of
Timeplex products. The only product warranties made by Timeplex, Inc., if any, are set
forth in the agreed terms and conditions for purchase of a Timeplex product. Timeplex, Inc.
disclaims liability for any and all damages that may result from publication or use of this
document and/or its contents except for infringement of third party copyright or
misappropriation of third party trade secrets. No part of this document may be reproduced
in any manner without the prior written consent of Timeplex, Inc.
U.S. GOVERNMENT RESTRICTED AND LIMITED RIGHTS
All software and related software documentation supplied by Timeplex, Inc. to the United
States Government are provided with Restricted Rights. Use, duplication, or disclosure by
the Government is subject to restrictions as set forth in subparagraph (c)(1)(ii) of the Rights
in Technical Data and Computer Software clause at DFARS 252.227-7013 or subparagraph
(c)(2) of the Commercial Computer Software – Restricted Rights at CFR 52.227-19, as
applicable.
All documentation, other than software documentation which are provided with Restricted
Rights, are provided with Limited Rights. U.S. Government rights to use, duplicate, or
disclose documentation, other than software documentation, are governed by the restrictions
defined in paragraph (a)(15) of the Rights in Technical Data and Computer Software clause
at DFARS 252.227-7013.
“DFARS” is the Department of Defense Supplement to the Federal Acquisition Regulation.
Contractor/manufacturer is Timeplex, Inc., 400 Chestnut Ridge Road, Woodcliff Lake, NJ
07675.
The information in this document is subject to change without notice. Revisions may be
issued at such time.
Express Routing, microLINK/2+, miniLINK/2+, LINK/100+, and TIME/VIEW are
trademarks of Timeplex, Inc.
Timeplex, Synchrony, Express Switching, LINK/2+, and entréeLINK+ are registered
trademarks of Timeplex, Inc.
Ethernet is a registered trademark of Xerox Corporation.
HP OpenView is a trademark of Hewlett-Packard Company.
CA-Ingres is a registered trademark of Computer Associates International, Inc.
OSF/Motif is a registered trademark of the Open Software Foundation.
Sun Microsystems and Solaris are registered trademarks of Sun Microsystems,
Incorporated. SunOS is a trademark of Sun Microsystems, Incorporated. SPARCstation is a
trademark of SPARC International, Incorporated, licensed exclusively to Sun
Microsystems, Incorporated.
X Window System is a trademark of Massachusetts Institute of Technology.
Synchrony GIM - October 1994
i
NOTICE
The company name Ascom Timeplex or Timeplex, Inc. is now Timeplex, LLC. The company logo
. In addition, please note the following:
is
•
•
Company addresses and phone numbers are as follows:
Americas
Europe/Middle East/Africa
Asia/Pacific
1619 North Harrison Parkway
Sunrise, Florida 33323-2802,
U.S.A.
Telephone: (800) 333-4143 or
(954) 846-1601
Fax: (954) 846-3935
Landata House, Station Road
Hook, Hampshire, RG27 9JF,
England
Telephone: 44 (0) 1256 763911
Fax: 44 (0) 1256 764717
c/o 1619 North Harrison Parkway
Sunrise, Florida 33323-2802,
U.S.A.
Telephone: (800) 333-4143 or
(954) 846-1601
Fax: (954) 846-3935
For service in the U.S. and Canada, contact Customer Support at 1-800-366-0126. For
service outside the U.S. and Canada, contact Customer Support at 44 (0) 1256 763911.
Please disregard any references to the company's former name, addresses, and phone numbers
in this manual.
Thank you.
1998, 2000 Timeplex, LLC
6/15/00
Summary Update
to the
®
Synchrony
General Information Manual
(MX17231-4)
Since the last printing of the Synchrony General Information Manual (MC17231), major product
developments of the Synchrony ST-1000 and Synchrony ST-20 bandwidth management systems
have included the following:

E3 Access
Call-by-Call Networking
ADPCM Echo Cancellation
SGM Support of 128-kbps
AD-10 Aggregate

SNMP Traps
Basic Rate Interface
Billing Agent
Voice over Frame Relay (VoFR)
Below is a brief summary of each of those major product developments.
E3 Access
The E3 Module (E3M) is an I/O module that provides physical layer connection to the 34.368Mbps E3 service. The E3M is a cost-effective interface for carrying multiple E1s containing ST1000/ST-20 INL data over leased E3 transmission facilities.
Designed to meet ITU-T Recommendations G.703, G.704, G.742, G.751, and G.823 for digital
multiplexers, the E3M is available in two models: E3M-1 and E3M-2. The E3M-1 is a single-port
E3 interface module that terminates up to 16 channelized E1 tributaries (ports) on the ST
add/drop bus. The E3M-2 is a dual-port E3 interface module that terminates up to 16 channelized
E1 tributaries on the ST add/drop bus. The E3M-2 also allows E1 tributaries of one E3 port to be
cross-connected to E1 tributaries of the other E3 port rather than be terminated on the ST bus.
June 1999
1999 Timeplex, Inc.
1
Call-by-Call Networking
In addition to the DPNSS and QSIG common channel signaling protocols, the D-Channel Server
Module (DSM) also supports ISDN Q.931 variants (ETSI Euro-ISDN and National ISDN-2) on
both primary rate and basic rate interfaces. Q.931 is an ITU-T recommendation describing Dchannel user-network messages for basic call control. For customer premise equipment (CPE)
that support Q.931, the DSM enables the ST network to emulate a private Integrated Services
Digital Network (ISDN) that supports call-by-call switching. The CPE can include PBXs for
voice calls and also routers, video codecs, and terminal adapters for voice or data calls.
SGM Support of
128-kbps AD-10 Aggregate
In addition to the SGM-1 and SGM-1/19.2K, the Subrate Groomer Module also includes the
SGM-1/128K module. The SGM-1/128K module allows an ST node to terminate 64-kbps and
128-kbps aggregates from the Synchrony AD-10.
ADPCM Echo Cancellation
The ASM models, ASM-16A/100 and ASM-16C/100, provide support of ADPCM echo
cancellation. Other ASM models include the ASM-16A and the ASM-16C.
SNMP Traps
The SNMP trap feature allows an ST node to generate an SNMP trap for each alarm. When
generated by an ST node, an SNMP trap is sent from the ST node to the appropriate SNMP
host(s). The SNMP host(s) can be either Synchrony NMS workstations or generic SNMP
managers, such as HP OpenView™. An SNMP trap contains the same information as that found in
the alarm record stored in the ST node and, as a result, the alarm does not need to be retrieved by
the SNMP manager.
Basic Rate Interface
The Basic Rate Module (BRM) is an I/O module that provides connection to basic rate ISDN
devices. The BRM operates at the physical layer connection to ISDN and provides
B-Channel handling and data flow control.
The BRM is designed to meet ANSI T1.601, ANSI T1.602, and ETS 300-047-1 through 5
Standards, as well as ITU I.430, Q.920, and Q.921 Recommendations. Two models of the BRM
are available: BRM/4-S and BRM/8-S to accommodate S/T interfaces. The BRM/4 type provides
four BRI interfaces and the BRM/8 type provides eight BRI interfaces.
The BRM can be used with the Call-by-Call Networking feature or as an I/O module to provision
INLs or TDM channels onto a BRI facility.
2
Synchrony GIM Update – June 1999
Billing Agent
This feature provides for the Billing Agent to collect and store Call Detail Record data on a
periodic basis. This data is made available to the user through TFTP file transfer, RMON MIB, or
an ST MIB.
Each node is capable of acting as a data concentrator so that one node can gather data from a
number of other nodes, providing a single interface to the network management system. Nodes
may be configured as redundant collectors, providing additional security to the user.
The Billing Agent collects the Call Detail Record data for billing purposes and stores the data in
memory, either volatile or nonvolatile.
Voice over Frame Relay (VoFR)
Synchrony ST now supports FRF.11, an implementation of the Frame Relay Forum that extends
frame relay applications to include the transport of digital voice payloads by multiplexing data link
connection identifiers (DLCIs) into sub-DLCIs. Synchrony ST VoFR support includes the
following features and applications:

Voice over Frame Relay Compression
Digit Translation Profiles
R2/MF Signaling
Interworking of DTMF and R2/MF Signaling
Traffic Shaping
Call-by-Call Networking of Packetized Voice
Permanently Connected Packetized Voice
VoFR Compression
The Voice over Frame Relay Module (VFM-16E/100) is a new server module that compresses
pulse code modulated (PCM) voice channels and packetizes them into FRF.11 sub-channels for
transport across the frame relay network via the Frame Server Module (FSM-64). The VFM
supports the following compression algorithms for Voice over Frame Relay (VoFR):

E-CELP (Enhanced Codebook Excited Linear Prediction), a proprietary algorithm that
compresses to 9600, 7466, or 4800 bps
G.729 CS-CELP (Conjugate Structure Algebraic Code Excited Linear Prediction) that
compresses to 8000 bps
3

G.726 ADPCM (Adaptive Differential Pulse Code Modulation) that compresses to
32000 bps
The VFM supports any mix of these algorithms, and can compress/decompress up to 16 voice
channels simultaneously.
Digit Translation Profiles
Digit Translation Profiles provide dialing plan flexibility for all Channel Associated Signaling
(CAS) voice circuits processed by the Voice over Frame Relay Module (VFM). In addition to the
inter-digit timeout typically used to determine the end of a called number sequence (the default
profile), Synchrony ST also offers users the ability to create profiles. Profiles define dial match
patterns (using a mask and/or special flag) and digit translation rules, which are used to modify
digits before routing the call.
Each TDM channel that carries packetized voice can be assigned up to eight different Digit
Translation Profiles for incoming voice calls and one for outgoing voice calls.
Using Digit Translation Profiles results in:

Faster call processing
Enhanced operation of the D-Channel Server Module (DSM)
Increased flexibility for network dialing schemes (for example, to accommodate speed
dialing, pre-pending for long-distance access numbers, and post-pending for source
call number representation)
R2/MF Signaling
R2/MF signaling refers to European analog and digital trunk signaling, which uses compelled
handshaking on every MF (multifrequency) signaling digit. The Voice over Frame Relay Module
(VFM) supports the digital version of R2 signaling as defined in ITU-T Q.440 and Q.441. R2/MF
Signaling Profiles are assigned on a TDM channel basis. Synchrony ST supports a wide range of
user-configurable parameters for each R2/MF Signaling Profile you create.
Synchrony ST supports both call-by-call (switching) and permanent voice connections with
R2/MF signaling.
Interworking of DTMF and R2/MF Signaling
Synchrony ST also supports the interworking between DTMF (such as FXS or FXO) voice
circuits on ST-1000/ST-20 or TimePlex FRADs (AD-10/FR2 or IAN-150) and R2/MF voice
circuits on either ST-1000/ST-20 or AD-10/FR2.
4
Traffic Shaping
When a frame relay channel enters an external frame relay network through a high-speed access
line (for example, from a central site) and is being fed to a low-speed access line (for example, a
branch site), the difference in the access rate at either end could result in data congestion. Packets
could become backed up at the egress of the network, ultimately disrupting the periodic arrival of
voice packets to the branch.
To prevent data congestion, Synchrony ST offers traffic shaping for frame relay channels. The
traffic shaping feature maintains a relative time separation between voice packets by regulating the
outbound data flow (towards the frame relay network) over a short-term period (approximately
20 ms) based on the access rate at the remote side.
Call-by-Call Networking of Packetized Voice
Synchrony ST supports call-by-call (switched) packetized voice channels that originate/terminate
on either an IAN-150, AD-10/FR2, or ST-1000/ST-20. Channel Associated Signaling (CAS)
circuits and Common Channel Signaling (CCS) circuits are both supported.
CAS circuits can use either DTMF (such as FXS or FXO) or R2/MF signaling protocol with the
ST-1000/ST-20 or the AD-10/FR2. For IAN-150, R2/MF signaling protocol cannot be used.
For CAS switched connections, the D-Channel Server Module (DSM) provides call setup and
release based on a proprietary message-based call control, PCC. The TimePlex FRADs and the
ST-1000/ST-20 VFM use the CAS protocol to support PCC. The PCC represents all of the
associated B-channels and connects as a packetized D-channel to the DSM. On a call-by-call
basis, the DSM then routes calls based on the dialed digit information contained in the PCC.
CCS circuits can be used with the ST-1000/ST-20 or the AD-10/FR2.
For CCS switched connections, the D-Channel Server Module (DSM) provides call setup and
release based on signaling generated from the CCS PBX. The VFM uses a forced connection for
the sub-channels.
Permanently Connected Packetized Voice
Synchrony ST also supports permanently connected packetized voice channels that
originate/terminate on either IAN-150, AD-10/FR2, or ST-1000/ST-20. Again, both CAS and
CCS circuits can be used.
For the permanent connections, neither ST-1000/ST-20 nor the TimePlex FRADs perform any
kind of interpretation of changes in line signaling for CAS circuits or interpretation of messages
for CCS circuits. All CAS line signaling changes or CCS messages are passed transparently from
end to end. A D-Channel Server Module (DSM) is not required.
5
Synchrony Family Overview
Providing integrated services bandwidth management, the Ascom
Timeplex Synchrony family is the optimal means for achieving
efficient service management for integrated networks. Designed to
deliver business-critical traffic efficiently and effectively, the
Synchrony family is comprised of bandwidth management systems and
advanced access systems. The bandwidth management systems are the
the central sites—the core elements—of a network, while the
advanced access systems provide branch networking to deliver costefficient edge-of-the-network connectivity.
Synchrony family bandwidth management systems include:
q
q
q
q
Synchrony ST - Full-featured voice and data backbone nodes
incorporating frame switching, circuit switching, and routing support.
ST nodes provide advantages over traditional TDM networking
products by incorporating integral support for constant bit rate (CBR)
as well as variable bit rate (VBR) traffic. Superior bandwidth
efficiencies are delivered by the patented Express Switching
architecture that ensures bandwidth is dynamically allocated to
applications as needed.
Synchrony NP-1000 - The building block of frame relay and packet
networks offering a range of communications options including frame
relay access, X.25 switching, and Ascom Timeplex dynamic routing.
The NP-1000 provides multivendor connectivity and powerful security
through built-in encryption, passwords, and closed user groups.
Synchrony TX-3 - An advanced broadband transmission system
created for today's T-3 and T-1 environment and designed to support
synchronous optical network (SONET) connectivity. The TX-3
(CEPT) supports E-3 and E-1 facilities.
Synchrony ER-5 - One of the most powerful and complete
internetworking solutions available today incorporating frame relay
switching for integrated traffic handling between locations. This
innovative approach reduces networking complexity and increases
bandwidth efficiency in the wide area.
Synchrony family advanced access systems include:
q
Synchrony AD - Data and voice branch access devices incorporating
packetized data handling and circuit switching. The AD group includes
remote termination units designed to operate with ST networks and
provide a cost-effective means to extend channel access to low-density
sites.
Synchrony GIM - September 1996
iii
q
q
q
Synchrony AR - Internetworking devices featuring extensive
multiprotocol routing and standards-based bridging. The AR group
provides efficient, cost-effective, and reliable local area network (LAN)
internetworking solutions for remote sites, small sites, or branch
locations.
Synchrony BNP - Branch access systems for networks based on serial
protocols. Offering a range of communications options including frame
relay access and X.25 switching, the BNP group supports one of the
industry's largest selection of serial protocols including asynchronous,
bisynchronous, Burroughs Poll/Select, and many others.
Synchrony IAN - Branch data networking systems that combine
several technologies—including access concentration, network-layer
routing, and frame and packet switching—onto a single platform. The
IAN group consolidates LAN and legacy traffic onto a single wide area
network, allowing you to deploy new LAN applications without
compromising the performance of your legacy applications.
As an added benefit of using the Synchrony bandwidth management
and advanced access systems, the Synchrony family also provides
network management support of its products. Among the network
management products are the Synchrony Network Management
System (SNMS), Element Management System 200 (EMS 200),
TIME/VIEW 2000, TIME/VIEW 2500, and TIME/VIEW 3000.
About This Manual
Among the Synchrony family of products, this manual focuses on the
Synchrony ST product line—ST-1000 and ST-20—the newest family
of wide area networking products from Ascom Timeplex. The manual
provides general information on the ST nodes, including their
interoperability with the various Synchrony access systems (AD, AR,
BNP, and IAN).
The information contained in this manual is divided into four parts:
q
q
q
q
iv
The first part introduces Synchrony ST and highlights the features and
benefits of an ST network.
The second part explains the network architecture, the network
management system, and the many application scenarios you can
implement with ST.
The third part provides an overview of the ST product family, and
describes the common equipment, I/O, server, and internetworking
modules that can be used by an ST node.
The fourth part offers a glossary of telecommunications terms and an
index.
How to Use This Manual
If you want to learn how Synchrony ST can satisfy your
telecommunications business needs, you may choose to read portions
of this manual or the entire manual. An Executive Summary is
included to provide you with an overview of the various sections
contained in this manual.
If you recently purchased an ST wide area network, you may decide to
browse or read this manual before referring to the other Synchrony
technical publications that accompanied your network equipment. For
more detailed information, the Synchrony documentation library
includes the following publications:
q
q
q
q
q
q
q
q
q
q
q
Synchrony™ ST-1000/ST-20 Bandwidth Management Installation and
Maintenance Manual
Synchrony™ ST-1000/ST-20 Bandwidth Management Configuration
Planning Manual
Synchrony™ ST-1000/ST-20 Craft Person Station User's Guide
Synchrony™ ST-1000/ST-20 Craft Person Station Command Reference
Manual
Enterprise Router Installation and Maintenance Manual
Enterprise Router User's Guide, Volumes I and II
Synchrony™ Network Management System Installation Manual
Synchrony™ Network Management System Administrator's Guide
Synchrony™ Network Management System User's Guide, Volumes I
and II
Synchrony™ AD-10 User's Guide
Synchrony™ AD-3/AD-7 User's Guide
v
Executive Summary
The Synchrony ST switching and transport systems are the most fullfeatured, state-of-the-art, bandwidth-efficient networking products
available today. To provide you with a brief overview of ST
networking, this Executive Summary presents a concise synopsis of
the following sections contained within this manual:
q
q
q
q
q
q
q
Introduction
Features and Benefits
Network Architecture
Network Management
Applications
Product Overview
Modular Node Design
Introduction
A significant challenge faces today's network administratorsto
deliver more services with less lead time, less budget, and fewer
resources. This challenge is a direct result of the changing network
environment. LANs are pervading the edges of the network and the
transition toward client/server system architecture is driving
processing power away from the host and onto the desktop. Data
requirements are also growing at enormous rates and the traffic mix is
becoming increasingly more "bursty." Yet, constant bandwidth
applications such as voice, high duty-cycle data, and subrate traffic
cannot be ignored since they continue to be mission-critical network
requirements.
An ST network is the ideal platform for today's communications
environment because it makes efficient use of bandwidth,
simultaneously manages packet and constant rate traffic in "native"
mode, offers single-module solutions to a variety of applications
needs, and is built on a 64-kbps foundation. This foundation increases
interoperability with carrier services, with existing Ascom Timeplex
equipment, as well as with other network elements.
vii
Executive Summary
An ST wide area network can grow and adapt in today's dynamic
telecommunications landscape. The endurance of an ST network is a
result of several highly effective systems features, including:
q
q
q
q
q
q
q
q
q
q
q
q
q
Express Switching architecture, which maximizes WAN bandwidth
utilization while guaranteeing application integrity
A unique hybrid switch that integrates frame relay and constant bit rate
(CBR) traffic
A platform capable for future technologies, notably Asynchronous
Transfer Mode (ATM)
High-quality voice compression using industry-leading algorithms
Private branch exchange (PBX) networking, which interprets common
channel signaling (CCS) protocols from PBXs to significantly improve
bandwidth efficiency across the ST network
Full compatibility with LINK/+ networks, as well as interoperability in
multivendor environments
A modular architectural design
A flexible, scalable framework that makes reconfiguration and
expansion economical and easy
System resiliency based on redundancy, load sharing, automatic
alternate routing, connection and frame delivery priorities
Carrier interoperability with public access networks
Integral LAN routing and bridging support
A comprehensive network management system
Compliance with industry standards
The key ST features translate into important networking benefits,
including:
q
q
q
viii
Bandwidth efficiency
"Bursty" packet and subrate capabilities
An orderly migration to ATM broadband services
Executive Summary
q
q
q
q
q
Full LAN internetworking capability
Protection of network investment
An open and industry-standard platform
Reliability and availability
Simplification of network maintenance
The core elements of an ST network are the nodes (ST-1000 and ST20), internodal links (INLs), access systems (AD, AR, BNP, and
IAN), and the network management system.
The backbone network formed by the ST nodes provides the basic
N x 64 kbps transport used by PCM voice and CBR data. By adding
server modules to the backbone, your network can also support
subnetworks. The Frame Server Module (FSM) represents the access
point to the packet subnetwork for frame relay and HDLC/SDLC
channels and to packet bypass functions at intermediate nodes. The
Subrate Groomer Module (SGM) represents the access point to the
subrate subnetwork and provides services that support transport, cross
connection, and termination of subrate channels.
ST network design efficiently separates input/output from processing
service and, as a result, is extremely flexible. Flexibility is illustrated
by the many types of ST connections. For example, connections can
be N x 64 kbps circuits, subrate circuits, or packet connections.
Connection endpoints can be input/output ports, server ports, or
demultiplexed output from servers.
All connections have associated channel profile parameters, which
control connection routing and monitor Advanced Bandwidth
Management (ABM) features (excluding grooming and bumping,
which are LINK/+ features). Additional channel parameters are
engaged for CBR connections and for packet connections. All
parameters are set by the network administrator.
ST employs a least-cost routing scheme that ensures the best available
path for a connection across the network. Routing is based on a cost
criteria, also defined by the network administrator. Finally, network
synchronization is derived by the distribution of reference timing
signals throughout the ST network.
ix
Executive Summary
Network Management
The Synchrony Network Management System (SNMS) is specially
designed to manage, monitor, and maintain your ST network. SNMS
uses the Simple Network Management Protocol (SNMP), the
CA-Ingres relational database, and the X Window System graphical
interface. In addition, SNMS is based on HP OpenView, the industry
leader in network management software. SNMS operates using a Sun
Microsystems workstation with the SPARC architecture.
SNMS is comprised of the following applications:
q
q
q
q
q
q
x
Topology Management, which features automatic network discovery
and a network topology map that is continuously updated. This
application also provides support of both ST and LINK/+ topology for
an ST-LINK/+ hybrid network (an ST network and a LINK/+ network
integrated via the LINK/+ Gateway Module).
Node Management, which shows a graphical representation of an ST
node and enables you to configure or modify internodal links, bundles,
channel and voice profiles, subrate and superrate channels, and frame
relay channels. Node Management also enables you to softload
upgrades. For an ST-LINK/+ hybrid network, Node Management also
provides support of the connections between LINK/+ nodes and the
connections between ST and LINK/+ nodes.
Alarm Management, which is integrated with the network topology
map and uses color-coded status to indicate the health of a node or
subnetwork. In an ST-LINK/+ hybrid network, Alarm Management
provides support of both ST and LINK/+ alarms.
Fault Management, which features connection and node diagnostics
and enables you to execute loopbacks on a node, shelf, module, or port
Security, which features network partitioning capabilities and the
creation of virtual private networks
Information Management, which features capabilities for collecting,
viewing, analyzing, and reporting on network performance
Executive Summary
Applications
An ST network is capable of handling a wide variety of applications.
Some of the more popular application scenarios you can implement
with ST include:
q
q
q
q
q
q
q
q
q
A constant bit rate private backbone network that supports a mix of
voice and data traffic among corporate locations
A voice/packet hybrid network that mixes constant and variable bit rate
traffic on a single platform
A frame relay switch network
A private voice network that uses PBX networking functionality to
significantly improve bandwidth efficiency and flexibility
An ST and LINK/+ fully integrated network via the LINK/+ Gateway
Module
An ST and LINK/+ interworking network at the DS0 and X.50 levels
A branch access network that allows LAN, legacy, and frame traffic to
travel over virtual circuits while it simultaneously delivers reliable
CBR connections for voice circuits
A campus/metropolitan network that uses currently installed copper to
provision two-wire access several kilometers from the ST node
An international network that switches or terminates traffic between T1
or E1 facilities
In addition, Ascom Timeplex worldwide customer support provides a
broad range of service and support programs to install, maintain, and
manage even the most complex enterprise networks anywhere in the
world.
xi
Executive Summary
Product Overview
The major building blocks of an ST network are the switching and
transport nodes (ST-1000 and ST-20) and the Synchrony advanced
access systems (AD, AR, BNP, and IAN). ST nodes, which comprise
the backbone infrastructure, are circuit-based networking multiplexers
and frame relay switches that handle N x 64 kbps circuit, packet, and
subrate channels simultaneously. Currently there are two models of ST
nodes:
q
q
ST-1000 for heavy trunk and I/O system requirements and voice/video
and frame-based application requirements. Also a high-performance
router/bridge, the ST-1000 handles direct LAN connection
requirements.
ST-20 for medium trunk and I/O system requirements and voice/video
and frame-based application requirements
Each ST node utilizes a unidirectional 160-Mbps looped bus that
provides synchronous cross-connect capabilities and has a
bidirectional 77.5-Mbps maximum user capacity. Nodes allow
termination of up to 31 internodal links and up to 480 local user I/O
ports operating at subrates and superrates. (A maximum of 480 user
I/O ports is achieved when an ST node is configured with sixty 8-port
SDMs. Up to 4,320 ports can be achieved using the AD-10, AD-7, and
AD-3 access devices described below.) Nodes are architecturally
modular and can be scaled to meet the evolving applications and
capacity requirements of your business.
The ADs are designed to extend the I/O capacity of an ST node and to
offer an inexpensive way to transport data and compressed voice from
the edges of the network to the backbone. The ADs allow multiple
signals (data, voice, fax, and video) to be transmitted simultaneously
over single digital communications circuits. The ADs are available in
three models:
q
q
q
xii
AD-10, a 24-port access device that concentrates voice, CBR, and
packet data streams for input to an ST node
AD-7, a six-port access device that provides cost-effective channel
extension to an ST node
AD-3, a two-port access device that provides cost-effective channel
extension to an ST node
Executive Summary
In addition to the ADs, the ARs, BNPs, and the IANs are also access
systems that cost-effectively deliver edge-of-the-network traffic to the
backbone ST node.
Modular Node Design
Synchrony ST provides a modular networking system that consists of
common equipment, I/O, server, and internetworking modules.
Common equipment modules include:
q
q
q
The Nodal Control Processor (NCP), which provides nodal
intelligence, controls the backplane, and performs clocking for an ST
node
The Right Expansion Module (RXM), which expands the ST-1000 bus
backplane from one shelf to the next or terminates the bus when it is in
the last (or only) shelf
The Left Expansion Module (LXM), which connects the intershelf
cables of an ST-1000 expansion shelf
I/O modules include:
q
q
q
q
The T1M, which provides four standard T1s with either DS1 or DSX-1
interfaces capable of supporting up to 24 channels of 64 kbps per
interface and operates at port data rates of full T1 or fractional T1
The E1M, which provides four standard E1 balanced and unbalanced
interfaces capable of supporting up to 31 channels of 64 kbps per
interface and operates at port data rates of full E1 or fractional E1
The Synchronous Data Module (SDM), which provides an interface for
synchronous user data operating at subrate speeds (less than 56 kbps)
and superrate speeds (up to 2.048 Mbps in multiples of 56 or 64 kbps).
The SDM can support local user I/O devices and/or internodal links
(INLs).
The Remote Termination Module (RTM), which provides a network
access point for the AD-7 or the AD-3 and allows these devices to
communicate with an ST node at distances up to 18,000 feet
xiii
Executive Summary
Server modules include:
q
q
q
q
q
The Frame Server Module (FSM), which processes and switches highlevel data link control (HDLC) frames, synchronous data link control
(SDLC) frames, and frame relay frames
The Subrate Groomer Module (SGM), which multiplexes and
demultiplexes channels below 56 kbps to and from a subrate aggregate
format and also terminates the AD-10
The Application Server Module (ASM), a digital signal processor
(DSP) that accepts downloaded application software such as Code
Excited Linear Prediction (CELP), Adaptive Transform Coding (ATC),
and Adaptive Differential Pulse Code Modulation (ADPCM) voice
compression and X.50 multiplexing
The D-Channel Server Module (DSM), which implements PBX
networking functionality by interpreting common channel signaling
(CCS) protocols that request call setup and teardown
The LINK/+ Gateway Module (LGM), which interfaces a LINK/+
Family network, creating an integrated ST and LINK/+ hybrid network
Internetworking modules, commonly referred to as independent
routing processors (IRPs), can accommodate the ST-1000 node. The
modules provide direct connections to IEEE 802.3/Ethernet II, IEEE
802.5/Token Ring, and FDDI LANs as well as V.11/RS-449 and V.35
wide area network, ISDN/BRI, and HSSI connections. Additionally,
the Independent Cell Processor (ICP) allows LAN-originating data to
be sent across a public ATM service.
****************
In conclusion, Synchrony ST provides the most bandwidth-efficient
platform available today for multi-service WAN backbone networks.
An ST network is feature-rich, flexible, scalable, and migratable.
Among its major offerings, ST incorporates frame switching, circuit
switching, and routing support. The industry-leading Express
Switching architecture of the ST network ensures that bandwidth is
dynamically allocated to applications as needed. Synchrony ST is the
optimal solution for both corporate and public network service
providers.
xiv
Contents
Introduction
1
The Changing Environment .......................................................... 1
Synchrony ST Bandwidth Management: the Concept.................... 2
Flexibility...................................................................................... 3
Interoperability: the 64-kbps Foundation ....................................... 3
Synchrony ST: Redefining Wide Area Networking........................ 4
5
Key System Features .................................................................... 5
Express Switching Architecture .................................................... 6
Integrated Frame Relay and CBR Support .................................... 8
Migration to ATM........................................................................ 9
Voice Compression ...................................................................... 9
PBX Networking.......................................................................... 9
LINK/+ Compatibility..................................................................10
Subrate Capability .......................................................................10
Modular Design...........................................................................10
Flexibility and Scalability .............................................................11
System Resiliency ........................................................................11
Access to Public Services ............................................................12
Integral Router Support...............................................................12
Comprehensive Network Management.........................................13
Benefits of Using the Synchrony ST Network ..............................13
xv
Contents
Synchrony Networking
15
Elements of a Synchrony ST Network......................................... 17
ST Nodes ................................................................................... 18
Synchrony Advanced Access Systems ......................................... 20
Internodal Links.......................................................................... 20
Network Management ................................................................ 21
Subnetworks............................................................................... 22
Packet Subnetwork..................................................................... 22
Subrate Subnetwork ................................................................... 24
Making Connections ................................................................... 26
Trunk Groups............................................................................. 32
Connection Parameters ............................................................... 32
Routing ...................................................................................... 36
Least-Cost Routing..................................................................... 36
Error Monitoring ........................................................................ 37
Network Synchronization ........................................................... 37
Nodal Clocking........................................................................... 38
Master Clocking Nodes .............................................................. 39
Network Management
41
Topology Management ............................................................... 43
Automatic Network Discovery.................................................... 43
Network Topology Map ............................................................. 43
Node Management...................................................................... 45
Internodal Link Management ...................................................... 45
Bundle Management ................................................................... 45
Profile Management.................................................................... 46
Subrate and Superrate Channel Management .............................. 46
Voice Circuit Management ......................................................... 46
Frame Relay Management........................................................... 47
Access Device Management........................................................ 47
Routing Table Management ........................................................ 47
Softload Upgradability................................................................ 48
xvi
Contents
Alarm Management .....................................................................48
Fault Management .......................................................................49
Connection Diagnostics ...............................................................49
Node Diagnostics ........................................................................50
Security .......................................................................................50
Network Partitioning Capabilities ................................................50
Information Management.............................................................52
Relational Database .....................................................................52
Billing and Accounting ................................................................52
Craft Person Station (CPS)..........................................................52
Applications
55
Other Ascom Timeplex Products .................................................56
Application Scenarios ..................................................................58
Traditional Application ................................................................58
Voice/Packet Hybrid Application.................................................60
Frame Relay Switch Application ..................................................61
PBX Networking Application ......................................................62
ST and LINK/+ Gateway Application ..........................................64
ST and LINK/+ DS0/X.50 Interworking Application ...................65
Branch Access Application ..........................................................66
Campus Application ....................................................................67
International Gateway Application...............................................68
Customer Support .......................................................................69
Installation...................................................................................69
Customer Support Center ............................................................69
Maintenance ................................................................................70
Training and Education................................................................70
Synchrony Product Family
Product Overview
71
Switching and Transport Nodes ...................................................72
The ST-1000 Node......................................................................73
The ST-20 Node..........................................................................80
xvii
Contents
Advanced Access Systems .......................................................... 81
Synchrony AD ............................................................................ 82
Synchrony AR ............................................................................ 94
Synchrony BNP .......................................................................... 95
Synchrony IAN........................................................................... 95
Synchrony Specifications ............................................................ 96
Modular Node Design
99
Common Equipment Modules................................................... 100
Nodal Control Processor........................................................... 101
Right Expansion Module........................................................... 102
Left Expansion Module............................................................. 103
I/O Modules ............................................................................. 103
T1 Module................................................................................ 104
E1 Module................................................................................ 106
Synchronous Data Module........................................................ 108
Remote Termination Module .................................................... 111
Server Modules ........................................................................ 112
Frame Server Module ............................................................... 113
Subrate Groomer Module ......................................................... 114
Application Server Module ....................................................... 116
D-Channel Server Module ........................................................ 118
LINK/+ Gateway Module ......................................................... 119
Internetworking Modules.......................................................... 121
Cable Management ................................................................... 122
Nodal Control Processor........................................................... 122
I/O Interface Modules............................................................... 122
Glossary and Index
Glossary ................................................................................... 125
Index ........................................................................................ 145
xviii
Introduction
The Synchrony family is designed
to empower the network manager
with the tools to succeed and excel.
W
elcome to the Synchrony family of bandwidth managers and
access systems from Ascom Timeplex.
Today's network managers are being asked to deliver more services
with less lead time, less budget, and fewer resources. To accomplish
this, the network must be efficient and use every advantage offered by
different carrier services. At the same time, the network must be
resilient enough to deliver uninterrupted services around the clock.
This is quite a challenge. With the Synchrony family, networks can
meet this challenge.
The Changing Environment
In the past, networks were fairly simple. There was a voice segment of
the network and a data segment. The data segment was made up of
many low-speed channels with each device having its own connection
to the host system controller. The voice section required PCM or
ADPCM support for analog or digital facilities. Generally, substantial
economies were gained by combining low-speed digital circuits and
PCM voice into T1s or E1s. Once installed, the network remained
fairly staticstatic by today's standards at least.
1
Introduction
Today, LANs are pervading the endpoints of the network. Groupware
and client/server architecture are driving the processing power from
the host to the desktop. Files are shared and, to a lesser degree,
applications are shared across the network. Network data requirements
are growing at enormous rates with requests for increased response
(bandwidth) being solicited to network managers every day. However,
voice, high duty-cycle data, and subrate traffic have not been
eliminated. These constant bandwidth applications continue to be a
requirement.
The industry has several solutions to this problem. The network
manager can install routers, bridges, LANs, DACSs, TDM
multiplexers, frame relay switches, and a host of other stand-alone
products to find a way to increased bandwidth efficiencies.
Or, the network manager can install Synchrony bandwidth
management systems.
Synchrony ST Bandwidth
Management: the Concept
Characteristics of network traffic are transitioning from constant bit
rate streams to variable bit rate streams. The transition is precipitated
by the move from structured applications to the bursty applications of
the internetworking world. Frame or packet technologies are designed
for and continue to be ideal for bursty traffic. However, these
technologies are ill suited for circuit-switched or constant bit rate
(CBR) traffic. CBR traffic, best exemplified by voice, continues to
require transportation in dedicated time slots in most networks.
The ideal platform in this environment is one that supports both
frame-based traffic and CBR traffic efficiently and effectively. Several
systems provide an overlay frame network on a TDM system and vice
versa, but only Synchrony ST is designed to manage both in "native"
mode. The revolutionary Express Switching infrastructure of the ST
platform provides the solution for merging frame-based traffic and
CBR traffic onto one transmission facility, while maintaining the
appropriate quality of service guarantees and ensuring the
exceptionally high reliability required of mission-critical networks.
2
Introduction
As a bandwidth manager designed with both frame- and circuit-native
support, ST simultaneously manages frame and circuit in the most
efficient manner possible. Circuit bandwidth is only used when
required. At all other times, the bandwidth is made available to the
frame traffic in order to increase the effective transfer rate to handle
bursts. By designing the system in this manner, maximum efficiency
can be achieved in a hybrid frame and CBR network. Bandwidth is
efficiently used.
Flexibility
The network manager must be able to implement a flexible network
one that can support new and varied applications quickly, with
minimal change or incremental investment to the network. Waiting for
the next budget cycle, redesigning a network, or installing a parallel
network are luxuries of the past.
Due to its server-based architecture, Synchrony ST provides the
network manager with single-module solutions. By simply adding an
appropriate server module, the network manager can enhance the
network, adding subrate data, compressed voice, frame switching, and,
in the future, Asynchronous Transfer Mode (ATM) access
applications. In the majority of cases, the infrastructure, common
control, and I/O interfaces are already in place. Applications can be
added with minimal network disturbance and minimal incremental
cost.
Interoperability: the 64-kbps
Foundation
Networks need to be interoperable with carrier services and other
network devices from a variety of vendors. As traffic moves into high
speeds, N x 64 kbps is quickly becoming a common denominator.
Synchrony ST is based on a 64-kbps architecture similar to the digital
cross-connect systems prevalent in carrier networks. This 64-kbps
building block is the foundation for providing interoperability to
carrier services, to existing Ascom Timeplex equipment, and to other
network elements. A standards-based system ensures that the network
is ready for a wide range of services from carriers. Proprietary
solutions become history and open systems become a reality.
3
Introduction
In addition to this interoperability, network routing and switching
become second nature. Besides being a true hybrid, ST is a crossconnect system capable of routing and switching large amounts of data
and voice. These capabilities make ST nodes a critical piece of a
backbone network fabric.
Synchrony ST: Redefining
Wide Area Networking
As you know, the landscape is changing for enterprise networks.
Flexibility, reliability, interoperability, and efficiency at low cost are
key requirements for network expenditures. High-speed frame traffic
is beginning to dominate, but low speed and circuit traffic will remain
for years. Services and competition from carriers are increasing at a
very exciting rate. Networks need to be nimble enough to take
advantage of these services.
Synchrony ST is designed to empower the network manager with the
tools to succeed and excel in this fluid environment. With its
bandwidth management, server architecture, hybrid core and
standards-based design, Synchrony ST is the bandwidth manager that
provides the most efficient system solution for integrated networking.
Now let's get to it!
4
If a network is to endure,
it must be capable of growing with traffic
loads and adapting to change . . . while
also maintaining high levels of
performance and reliability. . . .
n today's global economy, networks are clearly a key strategic
business asset. No company can afford to reinvest in a full
network infrastructure every time its business requirements
adjust or mature. As a result, network managers must make sound
network investments. If a network is to endure, it must be capable of
growing with traffic loads and adapting to changing application needs
and resource allocationswhile also maintaining high levels of
performance and reliability. Synchrony ST is designed to endure in
such a dynamic environment because it offers two layers of efficiency:
innovative technology and access to diverse public services.
I
Key System Features
A Synchrony ST wide area network offers a unique combination of
highly effective system features, which include:
q
q
q
q
Express Switching architecture
Integrated frame relay and constant bit rate (CBR) support
Migration to Asynchronous Transfer Mode (ATM)
Voice compression
5
q
q
q
q
q
q
q
q
q
Private branch exchange (PBX) networking
LINK/+ compatibility
Subrate capability
Modular design
Flexibility and scalability
System resiliency
Access to public services
Integral router support
Comprehensive network management
Express Switching Architecture
Synchrony ST offers the innovative Express Switching architecture, an
industry-leading approach to achieving bandwidth efficiencies while
maintaining the service levels required to preserve application
integrity. Express Switching architecture maximizes WAN bandwidth
utilization with Quality of Service.
The benefits of Express Switching architecture derive from basic
traffic integration. Constant bit rate (CBR) traffic (such as voice and
video) and variable bit rate (VBR) traffic (such as LAN data) can be
merged in a single system across a single carrier facility, with a
portion of the bandwidth reserved for CBR traffic and a portion
reserved for frame-based traffic. The CBR portion of the bandwidth
guarantees effective transport for delay-sensitive applications, and the
frame-based portion of the bandwidth guarantees effective transport
for delay-insensitive applications. Dynamic bandwidth allocation
ensures that the frame-based portion is allotted the maximum amount
of bandwidth possible.
Express Switching technology provides the answer to bandwidthefficient, high-performance, easily managed multiprotocol networks
including those where LAN and legacy data applications exist. A
standard feature in Ascom Timeplex internetworking products,
Express Switching technology allows a network manager to provide
qualities of service to individual data streams on an end-to-end basis.
These data streams can be prioritized by protocol, address, application,
6
or user—exactly the capability you need to ensure that businesscritical applications can share the same network on a noninterfering
basis with other less critical traffic.
Using a prioritized, connection-oriented infrastructure that delivers
traffic more quickly and more reliably than conventional routing, ST
nodes provide end-to-end prioritization of traffic. For example, the
priority of incoming traffic from the Ascom Timeplex internetworking
products is preserved as it traverses the ST backbone. This includes
traffic from the Synchrony AR, BNP, and IAN products. Figure 1
illustrates how an ST network prioritizes traffic.
IN
PRIORITY
QUEUES
L
INL
INCOMING
PRIORITIZED
TRAFFIC
IN
L
OUTGOING
PRIORITIZED
TRAFFIC
ST
NODE
and
= PRIORITY 1
= PRIORITY 2
= PRIORITY 3
Figure 1. End-to-End Traffic Prioritization
By dynamically allocating bandwidth based on traffic volume and
network priorities, the ST network efficiently handles CBR and
packet-switched transmissions. Dynamic bandwidth allocation permits
network design based on average traffic load, with peaks and
contending circuit-switched traffic sharing available bandwidth.
Bandwidth is rarely wasted or unused.
A least-cost routing algorithm automatically establishes new routes as
needed. Use of dynamic bandwidth allocation maximizes bandwidth
utilization to handle peak loads, reducing leased-line costs.
7
Integrated Frame Relay
and CBR Support
For more
information about
integrated frame
relay and circuit
switching, see
page 15.
Synchrony ST supports both packet switching and circuit switching by
integrating frame relay and CBR traffic on internodal links (INLs) and
switching 64-kbps circuit and frame traffic. ST nodes and AD devices
offer frame relay, CBR, and low bit rate voice (LBRV) to support
mixed traffic consisting of voice, LAN data, and circuit data.
Each INL contains a band for packet traffic and a band for CBR
traffic. Alleviating the requirement for dedicated management
bandwidth, supervisory and control traffic is carried in the packet band
along with user packet traffic.
The network administrator defines the minimum bandwidth available
for packet traffic and the minimum bandwidth available for CBR
traffic. The switching and access devices then automatically allocate
bandwidth to meet demands while staying within the constraints set by
the network administrator.
Packet bandwidth can range from 64 kbps to the entire bandwidth of
the INL. CBR bandwidth can range from 0 to 64 kbps less than the
entire bandwidth of the INL. The packet band expands and contracts
automatically based on the connections and disconnections of circuitswitched channels.
In bandwidth allocated to CBR traffic, the node can switch or
internally cross connect N x 64 kbps or N x 56 kbps channels. ST
supports synchronous devices operating at N x 56 kbps by padding the
channel to N x 64 kbps.
Packet-switching capabilities include standard frame relay interfaces,
standard high-level data link control (HDLC) point-to-point interfaces
for frame transport, idle suppression to support HDLC data over the
packet band, and LAN router access.
For packet switching, frame relay techniques are used in an internal
packet-switching network.
8
Migration to ATM
The innovative Express Switching architecture inherently provides the
type of bandwidth efficiencies and quality of service guarantees
expected from ATM. Synchrony ST provides the connectivity to
multiple traffic types that ATM promises. As reliable ATM services
become available, the ST platform will allow ATM migration with the
preservation of the underlying network investment.
Voice Compression
Integral voice compression is based on the highest quality voice
techniques that support Code Excited Linear Prediction/Adaptive
Transform Coding (CELP/ATC) and Adaptive Differential Pulse
Code Modulation (ADPCM). Using CELP software, voice processing
can be compressed to 5.33, 8, and 9.6 kbps. Using ATC software,
voice processing can be compressed to rates between 7.47 and 32
kbps. Industry-standard ADPCM compression is available at rates of
31.73 kbps and 36 kbps. The various compression choices offer
increased flexibility and maximum efficiency in voice processing.
Voice compression not only reduces the cost for voice-intensive
applications, but also provides reliable call connections and
extremely clear reception.
For information
about the
Application Server
Module (ASM),
see page 116.
For information
about AD-10
voice support,
see page 88.
PBX Networking
PBX networking uses the DPNSS or QSIG common channel signaling
(CCS) protocol to significantly improve bandwidth efficiency and
flexibility when managing voice traffic among multiple PBXs. PBXs
can be interconnected with an ST node to allocate bandwidth when
voice calls are set up. By supporting call-by-call switching and
allowing a direct connection between PBXs, the ST network can avoid
call tandeming and the subsequent degradation of voice quality if
voice compression is used.
For information
about the
D-Channel Server
Module (DSM), see
page 118.
9
LINK/+ Compatibility
LINK/+
SYNCHRONY
ST
For information
about the LINK/+
Gateway Module
(LGM), see
page 119.
As its name implies, the LINK/+ Gateway Module (LGM) provides a
gateway between LINK/+ and Synchrony ST networks, resulting in
the integration of LINK/+ and ST nodes in a single unified network.
Designed to enable current Ascom Timeplex users to preserve their
investment in hardware and software, the LGM allows existing
LINK/+ customers to add ST nodes and take advantage of the
advanced features offered by ST—features such as frame relay,
Express Switching architecture, and ATM migration. Without the
LGM, ST network elements can interwork with LINK/+ networks at
the DS0 and X.50 levels.
ST also provides interoperability in multivendor environments.
Synchrony products comply with industry standards including ANSI
standards, ITU-T and the Frame Relay Forum recommendations for
frame relay, CEPT and Bellcore standards for interfaces, and ETSI
standards for physical packaging.
Subrate Capability
Low-speed devices such as modems are economical and are still a
popular means of relaying low-priority data across the network.
Today's integrated networking solutions must continue to support
these low-speed data transmissions. Synchrony ST internodal links do
just that and can carry subrate data from 1,200 bps to 48 kbps.
For information
about the Subrate
Groomer Module
(SGM), see
page 114.
ST handles subrate data through the implementation of a subrate
grooming subsystem on top of the N x 64 kbps structure. The
subsystem allocates 64-kbps aggregates as required to connect
channels and uses a highly efficient proprietary multiplexing scheme
to stuff voice and/or data subrate streams into 64 kbps.
Modular Design
Synchrony ST supports a wide range of traffic switching and services
including circuit and frame. The modular design enables appropriate
new technologies to be added to nodes as the network grows and more
diverse application support is required or as more public services
become available. Modules can be inserted or removed from a node
without disrupting normal operations or other channel connections.
10
Flexibility and Scalability
A Synchrony ST network can start as a small utility network and then
expand as your needs grow. Reconfiguration is economical and easy.
As previously noted, the modular design of ST nodes makes it simple
for you to add new capabilities and services in the futurewithout
incurring any additional up-front costs or making existing hardware
obsolete. Only the appropriate I/O, server, or internetworking modules
need to be added.
Preprovisioning services in this manner enables network managers to
respond quickly to their users' ad-hoc requests for new network
serviceswithout the time, expense, and staff resources required to
plan, install, and support separate parallel networks.
In addition, the ability of Synchrony ST to access switched and
dedicated public services gives you maximum flexibility in selecting
the carrier services you want to offer your network users.
Implementing the appropriate public services can dramatically
improve the functionality and cost-effectiveness of your network,
which is why ST products are built to conform with N x 56/64 kbps
and frame relay interface standards.
System Resiliency
Many features contribute to the resiliency and systems availability of
Synchrony ST including distributed nodal intelligence, load-sharing
power supplies, automatic alternate routing, 16 levels of connection
priority, multiple levels of frame delivery priority, and automatic
discovery of network topologies. Combined with the high degree of
system redundancy, these features deliver the reliability needed to
support critical business applications.
ST control and transport modulesincluding the Nodal Control
Processor, T1 and E1 modules, servers, and expansion modulesare
fully redundant. Nodes are equipped with automatic fault recovery and
continually perform background diagnostics on redundant
components. This high degree of built-in system redundancy helps
prevent down-time, minimizes service outages, and maximizes system
availability of the ST network.
11
Access to Public Services
Synchrony ST networks can be deployed to provide any combination
of public circuit-switched, private circuit-switched, public frameswitched, and private frame-switched services.
ST nodes and AD access devices are based on 64 kbps (DS0), a
standard speed for digitizing a voice conversation using Pulse Code
Modulation. A T1 circuit accommodates 24 DS0 channels; an E1
circuit accommodates 31 DS0 channels.
Because the ST network is based on 64 kbps, it provides full carrier
interoperability with public access networks. The trend today is for
carriers to provide integrated services as well as bandwidth. ST
provides a low-cost carrier interface that allows your network to take
advantage of the numerous transport services now being offered.
In addition to providing interoperability with public networks, ST can
interface with private frame relay networks built to ANSI frame relay
standards, N x 64 kbps private networks, and virtual private networks.
ST networks will also complement Asynchronous Transfer Mode
(ATM) services and equipment by extending access to the ATM
network in the future.
By providing access to switched and dedicated public networks, ST
enables you to access the most cost-effective services for your
network.
Integral Router Support
In addition to being a hybrid circuit/frame switching and transport
system, Synchrony ST offers integral router support and direct
connections for Ethernet, Token Ring, and FDDI local area networks
(LANs). From the internetworking experience gained by Ascom
Timeplex, the ST platform incorporates full LAN capability that
includes multiprotocol routing and standards-based intelligent
bridging. Traffic can be routed using the Internet Protocol (IP), Xerox
Network System (XNS), Novell Internetwork Packet Exchange (IPX),
DECnet IV, AppleTalk, and Open Systems Interconnection (OSI)
network-layer protocols. In addition, ST supports transparent, source
route, source route transparent, and translation bridging.
12
Comprehensive Network Management
Using a comprehensive network management system, you can
monitor, manage, and administer your Synchrony ST network in an
open, standard software platform: OpenView from Hewlett-Packard.
Much of the system functionality, such as the generation of network
topology maps, the discovery of devices and their status, and the
diagnosis of network faults, is automatic. Standard features include
alarm monitoring, network partitioning, information management, and
softload upgradability. The system is also enhanced with ST-specific
features such as node management, bundle management, INL
management, and frame relay management.
For more
information, see
"Network
Management"
starting on page 41.
Because HP OpenView is an industry leader in network management
systems, you can also take advantage of additional third-party
HP OpenView compatible applications to satisfy your business needs.
Benefits of Using the
Synchrony ST Network
The ST network provides a number of important benefits to users
including:
q
q
q
q
q
q
q
q
q
q
q
Improved bandwidth efficiency of wide area facilities through the
patented Express Switching architecture
Ability to handle "bursty" packet applications
Hybrid design that increases network efficiencies by integrating circuit
and frame relay channels
Orderly migration to ATM broadband services and applications
Full LAN internetworking capability
Investment protection for future network requirements
Provisioning of multiple services through a single network platform
Compatibility across diverse network elements
Highly reliable and available backbone networking
Simplified maintenance with field-replaceable plug-in, pull-out modules
An open, standards-based network management solution that integrates
multiple technologies and equipment onto a single platform utilizing
industry-leading software
13
The design principles of Synchrony ST
. . . maximize flexibility to efficiently
and cost-effectively serve your business
communication needs today
and in the future.
W
q
q
hen designing and developing Synchrony ST,
Ascom Timeplex focused on accomplishing two primary
goals:
To provide the optimal mix of transport technologies and service access
required for today's traffic types and applications
To protect network investment by ensuring a migration path for future
applications
ST achieves these goals by supporting both frame relay and circuit
switching. At the node level, integration of constant bit rate (CBR)
and variable bit rate (VBR) traffic is realized through a hybrid switch
engine that combines true frame switching with true circuit switching.
Each type of traffic is conveyed in its natural formthere is no need
to convert one into the other and there is no overlay of one onto
another.
VBR
CBR
SYNCHRONY
ST
Packet switching is attained by a bid/grant mechanism that allows each
packet module access to each of the 32 packet bands supported by ST
nodes. Each module bids independently at one of three priorities for
each packet band.
15
Circuit switching is attained by directly transferring data from module
to module. Delays are small, typically 250 microseconds, from port to
port.
The "hybrid" switch allocates circuit and packet bandwidth on a
demand basiswhen circuit bandwidth is reduced, packet throughput
is increased. This is true within a node as well as between nodes.
Nodes can change circuit/packet bandwidth allocation without
disrupting live packet connections. Figure 2 illustrates the integration
of circuit switching and frame relay.
Expensive transmission resources are employed more efficiently by
integrating CBR and VBR traffic over internodal links (INLs) and by
ensuring the utilization of all available bandwidth.
ROUTER
PBX
T1/E1
FRONT-END
PROCESSOR
RESERVED FOR
CBR TRAFFIC
UNALLOCATED
BANDWIDTH
CAN BE USED
FOR CBR OR
FRAME RELAY
TRAFFIC
CIRCUIT BUS
VIRTUAL
PACKET BUS
SYNCHRONOUS
DATA
MODULE
FRAME
SERVER
MODULE
RESERVED FOR
FRAME RELAY
TRAFFIC
T1/E1
INTERFACE
MODULES
SYNCHRONY ST NODE
PBX TRAFFIC
TIME-SENSITIVE SNA TRAFFIC
SNA OR FRAME RELAY CARRIED AS PACKET
INL PACKET TRAFFIC
Figure 2. Integrating Circuit Switching and Frame Relay
This section outlines the design principles of the Synchrony ST family
and modules, and shows how the principles maximize flexibility to
efficiently and cost-effectively serve your business communication
needs today and in the future.
16
Also presented in this section is an overview of the following:
q
q
q
q
q
Elements of a Synchrony ST network
Subnetworks
Making connections
Routing
Network synchronization
Elements of a Synchrony ST
Network
The core elements of a Synchrony ST network include the switching
and transport nodes (ST-1000 and ST-20), the internodal links (INLs)
that interconnect them, the Synchrony access systems (AD, AR, BNP,
and IAN) that can be used to extend the I/O capability of an ST node,
and the network management system. Figure 3 illustrates a five-node
ST network.
ST-1000
ST-1000
ETHERNET LAN
ETHERNET LAN
AD-10
ST-1000
IAN
AD-10
NEW YORK
SAN FRANCISCO
CHICAGO
WOODCLIFF LAKE
LONDON
NETWORK
MANAGEMENT
WORKSTATION
ST-1000
AD-7
ST-20
AD-3
AD-7
AD-3
ETHERNET
INL
IAN
Figure 3. Five-Node ST Network
17
ST Nodes
The ST-1000 and ST-20 nodes are the pivotal network elements of an
ST network. The ST-1000 is expandable to four shelves, while the ST20 is a single-shelf unit. Node particulars such as bus backplane,
chassis and shelving, and power distribution are discussed in detail in
the "Product Overview" section included in the "Synchrony Product
Family" portion of this manual.
ST nodes are modular in design. Modules can be categorized as
common equipment, I/O, or server modules. The ST-1000 also
accommodates internetworking modules, which are commonly
referred to as independent routing processors (IRPs).
Common equipment modules include the Nodal Control Processor
(NCP), the Left Expansion Module (LXM), and the Right Expansion
Module (RXM). The NCP provides all nodal control and clocking
functions. The LXM extends the bus across shelves in an ST-1000
multiple-shelf configuration, while the RXM terminates or extends the
ST-1000 bus depending on the number of shelves.
For more information
about modules, see
"Modular Node Design"
I/O modules include the T1 Module (T1M), E1 Module (E1M),
Synchronous Data Module (SDM), and Remote Termination Module
(RTM). These modules provide the physical interface for connections
to user devices, external networks, Synchrony access systems, and
other ST nodes.
ST nodes are based on a 64-kbps infrastructure that is inherently
compatible with any network that meets the framing and
channelization standards deployed in public networks. The interface to
N x 64 kbps public and private networks is provided by the T1M and
E1M modules. Access to channelized services for T1/E1 (and
FT1/FE1) is made possible along with support for multiple traffic
types. An ST node supports bundles in sizes from 1 to 24 (T1) or 1 to
31 (E1) time slots to support channelized services. T1M modules
support up to 24 bundles per port; E1M modules support up to 31
bundles per port. Each bundle can be defined as an INL or be directed
to an INL for transport across the wide area or to different server
modules for processing. Figure 4 illustrates how channelized services
support a variety of traffic types.
18
T1M
FRAME RELAY
FRONT-END
PROCESSOR
6 TIME SLOTS
AD-10
AD-10 AGGREGATE 1 TIME SLOT
PCM
3 TIME SLOTS
P
ST
NODE
INL
6 TIME SLOTS
O
R
T
VIDEO
N x 64 KBPS
6 TIME SLOTS
1 TIME SLOT
IAN
FOREIGN
NETWORK
X.50
1 TIME SLOT
Figure 4. T1/E1 Channelized Service
Server modules include the Subrate Groomer Module (SGM), Frame
Server Module (FSM), Application Server Module (ASM), D-Channel
Server Module (DSM), and LINK/+ Gateway Module (LGM). Each
server module performs a specific function or data transformation and
can process data forwarded from multiple I/O modules.
The server module services are independent of the I/O interface and
transmission facilities. This allows a node to be equipped for the
specific technology required today, while providing a simple
19
migration path to exploit a wide variety of new telecommunications
products and service offerings.
The separation of I/O and processing service allows total I/O and
service capacity to be optimized and is fundamental in providing the
flexibility required in a heterogeneous and evolving network
environment. Additional server modules can easily be added to
increase service capacity or diversity. If requirements for access to
service change, I/O module or access device configuration can be
modified without replacement of server modules.
Synchrony Advanced Access Systems
about the Synchrony
advanced access
systems, see page 81.
Synchrony advanced access systems cost-effectively deliver edge-ofthe-network traffic to an ST node. Access systems include the
following groups:
q
q
q
q
AD, comprised of the AD-10, AD-7, and AD-3
AR, comprised of the AR-350, AR, and AR-150
BNP, comprised of the BNP-350 and BNP
IAN, comprised of the IAN and IAN-150
The access systems meet the diverse requirements of branch
networking and deliver traffic economically to an ST node.
Internodal Links
Internodal links (INLs) provide for efficient use of transmission
resources through dynamic bandwidth allocation between frame relay
traffic (VBR) and circuit traffic (CBR). As channel connection
requirements within the network change, the boundary between traffic
types over an INL can shift in 64-kbps increments within the limits
defined by the network administrator.
Setting minimum available bandwidth for each traffic type ensures
that the network is always able to meet its normal traffic demands.
The minimum bandwidth segments are referred to as "hard decks."
Between the "hard decks" is an area of "breathable bandwidth." The
breathable portion is available for use by either CBR or VBR traffic as
needed, depending on certain priorities defined and configured by the
network manager. Dynamic bandwidth allocation is accomplished
20
with minimum circuit complexity and allows the packet or CBR
boundary to move asynchronously in an INL without interruptions of
data transmission. Figure 5 illustrates how bandwidth allocation can
shift between CBR and VBR traffic across an INL.
CBR TRAFFIC
CBR
ALLOCATION
CBR
"HARD DECK"
CBR
BANDWIDTH
CONTENTION
FRAME RELAY
BANDWIDTH
ALLOCATION (CIR)
FRAME RELAY
"HARD DECK"
FRAME RELAY BURSTS
(USER DEMAND)
VBR TRAFFIC
Figure 5. Breathable Bandwidth
Applications based on frame relay are the most likely beneficiaries of
dynamic bandwidth allocation. At any given moment, the frame relay
traffic that needs to cross an INL may be more than the VBR
minimum allocation. Any bandwidth not being utilized can be utilized
temporarily by the VBR segment, without interrupting any other
traffic flows on the INL. This is one way in which traffic presented to
a frame relay interface can temporarily exceed CIR.
In addition to sharing bandwidth between CBR and VBR traffic, ST
allows the packet band bandwidth to be shared among the different
VBR channels. When one channel is idle, its allocated packet band
bandwidth is available for transmission of excess information of other
packet channels. As a result, the use of available bandwidth is
maximized for all active sources of packet traffic.
Network Management
The Synchrony Network Management System (SNMS) is specially
designed to monitor and control ST nodes and AD access devices. The
system is a standards-based open platform that uses the Simple
Network Management Protocol (SNMP) and the CA-Ingres relational
database to provide a unified view of the network.
For more information, see
"Network Management"
21
SNMS communicates with the NCP, which employs an internal packet
protocol for system communication. Traffic, including communication
with network management, is carried over the packet subnetwork
along with any other packet traffic entering the packet subnetwork.
Subnetworks
The backbone network that is formed by the ST nodes provides the
basic N x 64 kbps transport used directly for PCM voice and CBR
data. The backbone network can also support two subnetworks:
q
q
SUBRATE
BACKBONE
PACKET
A packet subnetwork (for frame relay and packet data)
A subrate subnetwork (for CBR data at rates below 56 kbps)
The subnetworks reside on the basic N x 64 kbps transport layer and
are implemented by server modules. The Frame Server Module (FSM)
is the access point to the packet subnetwork for frame relay and
HDLC/SDLC channels and to packet bypass functions at intermediate
nodes. The Subrate Groomer Module (SGM) is the access point to the
subrate subnetwork and provides services that support transport, cross
connection, and termination of subrate channels.
Packet Subnetwork
The packet subnetwork efficiently handles and transports the growing
volume of frame relay and LAN-to-LAN data. This subnetwork can
also carry older SNA traffic that uses HDLC/SDLC protocols.
Synchrony ST employs an internal packet protocol based on frame
relay principles to transport packet data. In frame relay, the logical
connection between two endpoints is called a virtual circuit. The FSM
supports permanent virtual circuits (PVCs) set up by the network
manager. Once a PVC is established, data can be sent. However, the
bandwidth across the path is used only when data is sent.
Unlike conventional packet-switching protocols, which have explicit
source and destination header information, frame relay headers include
only a data link connection identifier (DLCI). Channel connections
within the packet subnetwork are configured as PVCs that are
identified by DLCIs. Figure 6 illustrates a frame relay frame.
22
FLAG
DLCI
FECN
BECN
DE
FRAME
RELAY
HEADER
USER
DATA
USER
DATA
FRAME
CHECK
SEQUENCE
(FCS)
FLAG
DATA LINK CONNECTION IDENTIFIER
FORWARD EXPLICIT CONGESTION
NOTIFICATION
BACKWARD EXPLICIT CONGESTION
NOTIFICATION
DISCARD ELIGIBILITY
Figure 6. A Frame Relay Frame
ST transports packets over PVCs, mixing packets from multiple
sources over the same physical transmission circuits, and therefore
avoids circuit-switching inefficiencies.
Access to the packet subnetwork is managed by the Frame Server
Module (FSM), which performs the following:
q
q
q
q
q
q
Segments and reassembles user packet data at connection endpoints
about the Frame Server
Module (FSM), see
page 113.
Forwards packets at intermediate nodes
Records packet statistics
Supports HDLC/SDLC protocols by encapsulating the data in frames at
the FSM to allow transport across the packet subnetwork
Manages PVC connections and disconnections
Releases PVCs when no longer required
Depending on the protocol used, incoming packets can vary from 4 to
4,096 bytes in length. ST divides these packets into segments. Each
segment contains up to 240 user bytes with a 15-byte overhead and is
used for transport across the packet subnetwork. By segmenting longer
frames for transport, transit delays are reduced for high-priority traffic
and short packets. In addition, competition between packet traffic of
differing priority is more quickly resolved.
Nodes equipped with at least one FSM are considered part of the
packet subnetwork. These nodes can adapt incoming packets to the
internal packet format in preparation for transport or can bypass
23
packet subnetwork traffic at intermediate nodes. Figure 7 illustrates
packet subnetwork node eligibility.
FRAME
TRAFFIC
NODE
1
2
3
4
5
6
FRAME
TRAFFIC
NODE 2
FSM
FSM
NODE 1
NODE 3
MODULES
REQUIRED
FSM
FSM
FSM
FSM
NODE 4
=PACKET
SUBNETWORK
NODE 5
= FRAME TRAFFIC
NODE 6
NOTE: Without an FSM in node 4, the packet subnetwork between node 1 and node 3 would be
disjointed. Although each node would be able to handle packet traffic independently, a packet
connection between node 1 and node 3 would not be able to be made.
Figure 7. Packet Subnetwork
Subrate Subnetwork
about the Subrate
Groomer Module
(SGM), see page 114.
24
The Subrate Groomer Module (SGM) provides termination and cross
connection of synchronous data at rates below 56 kbps. Subrate data is
forwarded to the SGM from synchronous ports or from other server
modules (for example, compressed voice from the ASM). At the
SGM, subrate channels are multiplexed into subrate aggregate format
(SAF) in data streams of 64 kbps for transport across the network. In
the reverse direction, the SGM demultiplexes SAFs into the
component subrate channels for cross connection to other SAFs or for
termination.
The SAF used to transport subrate data is extremely efficient,
requiring only 400 bps for overhead per 64 kbps, with a payload of
63.6 kbps. (By comparison, the ITU-T standard X.50 format provides
only a 48-kbps payload.)
The SGM can also groom channels originating at an AD-10 access
multiplexer and can terminate AD-10 channels at an ST node.
When a channel is terminated, the SGM puts it into subrate channel
format (SCF) for transport across the ST bus in a 64-kbps data stream
to an I/O module.
All network nodes are considered part of the subrate subnetwork
including the following:
q
q
Nodes equipped with SGM to terminate and route subrate traffic
Nodes not equipped with SGM since they are still able to bypass
bundles of subrate channels that are aggregated in 64-kbps data streams
Figure 8 illustrates coexisting subrate and packet subnetworks.
FRAME
TRAFFIC
NODE
1
2
3
4
5
MODULES
REQUIRED
FSM
FSM
FSM
SGM
SGM
FSM
FSM
NODE 1
FRAME
TRAFFIC
NODE 2
FSM
NODE 3
SGM
SUBRATE
TRAFFIC
=SUBRATE
SUBNETWORK
NODE 4
SGM
NODE 5
= SUBRATE TRAFFIC
SUBRATE
TRAFFIC
= FRAME TRAFFIC
Figure 8. Subrate Subnetwork
25
Making Connections
Synchrony ST network connections are defined as any path between
two endpoints. Connection endpoints can be I/O ports, server ports, or
demultiplexed output from servers. Because server modules have no
external physical interfaces, channel connections are made over the ST
bus to connect the servers to the appropriate interfaces. These
connections carry data to servers from I/O ports or from other servers.
Figure 9 and Figure 10 illustrate the hierarchy of elements and
connection points within an ST network.
T1M
T1 PORT
E1M
E1 PORT
BUNDLE
Identifies a connection
point for one or more
64-kbps data streams
SDM
RTM
SYNCHRONOUS
DATA PORT
point for a subrate,
N X 56 kbps, or
N x 64 kbps data stream
2B1Q
PORT
1B OR 2B
BUNDLE
Figure 9. I/O Modules: Hierarchy of Elements and Connections
26
ASM
CELP/ATC PORT
point for a 64-kbps
PCM circuit destined
for CELP/ATC
transcoding
ADPCM PORT
point for a 64-kbps
PCM circuit destined
for ADPCM transcoding
X.50 PORT
point for a 64-kbps
X.50 data stream
X.50 CIRCUIT
point for a subrate
channel extracted from
or destined for an
X.50 data stream
DSM
FSM
FRAME SERVER PORT
Identifies an access point
to the packet subnetwork
for a frame relay or HDLC/
SDLC access channel
D-CHANNEL PORT
Terminates the D-channel
signaling messages
from a PBX interface
INTER-DSM
COMMUNICATIONS PORT
(IDCP)
Identifies an access point
to the packet subnetwork
for an inter-DSM
communications channel
INTER-DSM
COMMUNICATIONS
CHANNEL (IDCC)
Identifies the endpoint
for a permanent virtual
circuit defined to
transport DSM-to-DSM
communications
FRAME RELAY CHANNEL
Identifies the endpoint
for a permanent virtual
circuit defined to
transport frame relay
or HDLC/SDLC frames
SGM
SGM/AG PORT
point for a 56- or
64-kbps AD-10
aggregate data stream
AD-10 DATA PORT
point for a data channel
extracted from or
destined for an AD-10
aggregate
AD-10 VOICE PORT
point for a voice channel
extracted from or
aggregate
PACKET BAND
point for an AD-10 packet
band extracted from or
aggregate
LGM
SGM SAF PORT
point for SAF ports
IAF PORT
point for an N x 56 kbps
or N x 64 kbps
ILC aggregate format
(IAF) stream
SUBRATE
CHANNELS
LINK/+ CHANNEL
point for a LINK/+ channel
extracted from the IAF
stream for termination
at an ST node or LINK/+
node
Figure 10. Servers: Hierarchy of Elements and Connections
27
Depending on application requirements, an end-to-end network
connection may be defined as a series of concatenated connections.
For example, Figure 11 shows how HDLC data destined for the packet
subnetwork can enter the ST network as part of a T1 64-kbps X.50
channel. One connection must be defined to transport the 64-kbps T1
bundle to an ASM module where the component subrate channels are
demultiplexed. Another connection must be defined to transport the
HDLC data to an FSM, where the required PVC is defined. The last
connection transports the data to a synchronous data port, which
constitutes the network endpoint.
Connection between the T1
BUNDLE defined at a T1M
PORT and an ASM X.50 PORT.
Connection can span nodes if
necessary.
HDLC
Subrate
Data
SDM
T1M
X.50
MUX
HDLC
DEVICE
SUBRATE
ASM SUBNETWORK
Connection between the
X.50 CIRCUIT defined at the
ASM X.50 PORT and a
FRAME SERVER PORT.
The X.50 circuit consists of
HDLC subrate data
extracted from the X.50
bundle at the ASM.
Connection can span
nodes if an SGM is in the
same node as the ASM.
SYNCHRONY
NETWORK
FSM1
FSM2
PACKET
SUBNETWORK
Connection between endpoints
of a permanent virtual circuit (PVC).
FRAME SERVER CHANNELS defined
at each FRAME SERVER PORT
define the PVCs required at the port.
Connection between
a FRAME SERVER
PORT and a
SYNCHRONOUS
DATA PORT.
A remote subrate TDM
connection can span
nodes if an SGM is
located at each
connection endpoint. If
the connection is
N x DS0, then no SGM
is needed.
Connection endpoint
Permanent virtual circuit
TDM connection
Figure 11. End-to-End HDLC Network Connection
28
Figures 12 and 13 delineate examples of the types of connections
available within the ST network. The simplest connections involve
only I/O modules as depicted in Figure 12. The true flexibility of the
ST network becomes apparent as connections are explored between
I/O and server modules and between server modules as shown in
Figure 13. Note that a synchronous data port, as represented in Figures
12 and 13, can be a port from a Synchronous Data Module (SDM) or a
port from AD-7/AD-3 access devices.
Connections can be local (within the same node) or remote (spanning
nodes). Connections within the network can be defined as automatic
(internal connect request issued when the associated module or port is
online) or user-initiated (internal connect request issued upon user
command only). For bandwidth contention channels, connect requests
are issued only when the appropriate control signals are asserted for
synchronous data ports or when the appropriate hook state is asserted
for voice ports.
SYNCHRONOUS
DATA PORT
SYNCHRONOUS
DATA PORT
SYNCHRONOUS
DATA PORT
AD-10 TDM
DATA PORT
SYNCHRONOUS
DATA PORT
T1/E1 BUNDLE
T1/E1 BUNDLE
T1/E1 BUNDLE
AD-10 TDM
DATA PORT
AD-10 TDM
DATA PORT
Figure 12. I/O-to-I/O Connections
29
ASM
X.50 CIRCUIT
LINK/+ TDM
CHANNEL
LINK/+ TDM
CHANNEL
X.50 PORT
X.50 CIRCUIT
X.50 CIRCUIT
SYNCHRONOUS
DATA PORT
X.50 PORT
X.50 CIRCUIT
AD-10
TDM DATA PORT
T1/E1 TIME SLOT
X.50 PORT
X.50 CIRCUIT
SYNCHRONOUS
DATA PORT
X.50 CIRCUIT
FRAME SERVER
PORT
T1/E1 TIME SLOT
ADPCM, CELP/ATC
PORT
ADPCM, CELP/ATC
PORT
AD-10 VOICE PORT
(CELP ONLY)
LINK/+ CELP
CHANNEL
LINK/+ ADPCM
CHANNEL
SGM/AG SERVICE
LINK/+ TDM
CHANNEL
SGM/AG PORT
SYNCHRONOUS
DATA PORT
SGM/AG PORT
T1/E1 TIME SLOT
SGM/AG PORT
AD-10
PACKET BAND
FRAME SERVER
PORT
AD-10
TDM DATA PORT
FRAME SERVER
PORT
AD-10
TDM DATA PORT
SYNCHRONOUS
DATA PORT
AD-10
TDM DATA PORT
AD-10
TDM DATA PORT
AD-10
TDM DATA PORT
X.50 CIRCUIT
AD-10
TDM DATA PORT
LINK/+ TDM
CHANNEL
AD-10
VOICE PORT
AD-10
VOICE PORT
AD-10
VOICE PORT
ASM CELP/ATC
PORT
AD-10
VOICE PORT
LINK/+ CELP
CHANNEL
Figure 13 (Part 1). I/O-to-Server and Server-to-Server Connections
30
FSM
X.50 CIRCUIT
FRAME SERVER
PORT
AD-10
PACKET BAND
FRAME SERVER
PORT
AD-10 TDM
DATA PORT
FRAME SERVER
PORT
SYNCHRONOUS
DATA PORT
FRAME SERVER
PORT
T1/E1 BUNDLE
FRAME SERVER
PORT
LINK/+ TDM
CHANNEL
FRAME SERVER
PORT
FRAME RELAY
CHANNEL (PVC)
FRAME RELAY
CHANNEL (PVC)
INTER-DSM
COMMUNICATIONS
PORT (IDCP)
INTER-DSM
COMMUNICATIONS
CHANNEL (IDCC)
DSM
T1/E1
BUNDLE
D-CHANNEL
PORT
LGM
SYNCHRONOUS
DATA PORT
LGM PORT
LINK/+ TDM
CHANNEL
SYNCHRONOUS
DATA PORT
T1/E1 BUNDLE
LGM PORT
LINK/+ TDM
CHANNEL
T1/E1 BUNDLE
LINK/+ TDM
CHANNEL
LINK/+ TDM
CHANNEL
LINK/+ TDM
CHANNEL
SGM/AG PORT
LINK/+ TDM
CHANNEL
FRAME SERVER
PORT
LINK/+ TDM
CHANNEL
X.50 PORT
LINK/+ TDM
CHANNEL
X.50 CIRCUIT
LINK/+ TDM
CHANNEL
AD-10
TDM DATA PORT
LINK/+ CELP
CHANNEL
ADPCM, CELP/ATC
PORT
LINK/+ CELP
CHANNEL
AD-10
VOICE PORT
LINK/+ ADPCM
CHANNEL
ADPCM, CELP/ATC
PORT
Figure 13 (Part 2). I/O-to-Server and Server-to-Server Connections
31
Trunk Groups
Trunk groups allow telephones or fax machines to contend for
compressed voice channels that connect to a range of remote
telephones or fax machines. Trunk groups work together in pairs. Each
trunk group of a pair can be at the same node (except for ASM voice
trunk group pairs) or at different nodes. Going off-hook at the device
associated with the source trunk group causes the call to contend for a
connection to a device associated with the destination trunk group.
The destination trunk group can span multiple I/Os within one T1/E1
port or within multiple AD-10 ports.
Overlapping trunk groups can be configured so that two or more
source trunk groups share circuits at the destination end. Reciprocal
trunk groups can be configured using two separate trunk group pairs if
bidirectional voice traffic is relatively balanced.
The following types of trunk groups are available:
q
q
Application Server Module (ASM) voice trunk groups in which
CELP/ATC or ADPCM voice compression is performed by the ASM.
These trunk groups support digital PBX connections.
AD-10 trunk groups in which CELP/ATC compression is performed by
the AD-10. These trunk groups support AD-10 connections.
Connection Parameters
There are three types of connections: N x 64 kbps, subrate, and packet
connections. All connections have associated channel profile
parameters, which monitor connection features and control connection
routing. Besides channel profile parameters, CBR connections require
appropriate parameters while packet connections require alternative
parameters.
Channel Profile
A channel profile consists of a set of parameters that include
connection priority, maximum allowable bit error rate (BER), facility
characteristics, hop count, and satellite hops. Each channel is assigned
a profile; one profile can be assigned to multiple channels. It is also
possible to override channel profile requirements and to specify the
path for a connection as long as partition requirements are not
violated.
32
Connection Priority
In the ST network, the sequence of attempted connections is made
based on the level of priority (1 through 16) assigned to each channel
connection. The priority scheme does not disrupt any channels already
connected, even if those connections have a lower priority than the
ones waiting to be connected.
Maximum Allowable Bit Error Rate
When devising a connection path for a particular channel, the network
will only choose from INLs that have a bit error rate (BER) less than
the threshold set by the channel's assigned profile. In addition, ST
nodes monitor INL BERs, and, if the rate exceeds the threshold, the
system disconnects channels on that INL and reroutes them over INLs
with more suitable BERs.
Facility Characteristics
A channel's assigned profile can further restrict the selection of a
connection path. This is accomplished by limiting connections to only
those INLs possessing certain characteristics. For example, you may
want your connection to follow a terrestrial path only, or you may
want to ensure that the connection is made over encrypted INLs only.
Hop Counts and Satellite Hops
Each traversal across an INL is considered one "hop." As part of the
channel profile, Synchrony ST allows you to set a maximum of 16
hops per end-to-end connection.
ST also allows you to set a maximum of 5 satellite hops per end-toend connection.
CBR Parameters
In addition to the channel profile, the network manager also sets the
following parameters per channel for constant bit rate traffic:
q
q
q
Speed as required by a particular application's data format
Signal pattern generated when the port is out of service
Signal processing performed on incoming traffic
33
Packet Parameters
Measurement Interval
(T) = Bc/CIR
Within the packet subnetwork, ST nodes manage the traffic associated
with each PVC individually and ensure optimum traffic-carrying
capacity. The nodes assign internal resources to each PVC based on
user-configurable information rates and burst sizes per PVC. The
standard time interval over which rates and burst sizes are measured is
called the Measurement Interval (T), which is not user-specified. In
general, the duration of T is proportional to the length of burst.
User-configurable rates and bursts are defined as follows:
q
q
q
Committed Information Rate (CIR): Rate at which the network
guarantees to transfer information under normal operating conditions
Excess Information Rate (EIR): Maximum rate at which the network
attempts to deliver data over a measurement interval (T)
Committed Burst Size (Bc): Maximum amount of data that the network
agrees to transfer under normal operating conditions over a measurement
interval (T)
One additional parameter, not specified by the user, is factored into
PVC traffic management:
Excess Burst Size
(Be) = EIR % T
q
Excess Burst Size (Be): Maximum amount of uncommitted data
that the network attempts to deliver over a measurement interval (T)
The measurement interval (T) represents a sliding window. The arrival
of packets independently and asynchronously triggers the interval's
starting point. The CIR determines how much packet bandwidth to
allocate for the respective PVC, while Bc directly impacts buffering
requirements. Since EIR traffic is always a low priority, it is only
serviced after the CIR traffic of all PVCs of that packet band is
delivered. Figure 14 represents the relationships between the packet
traffic parameters and provides an example of compliant, excess, and
discarded data flow.
Besides managing traffic for individual PVCs through CIR and Bc, the
packet subnetwork performs "rate enforcement" to ensure that the sum
of all CIRs (plus the ARQ requirements) does not exceed the
bandwidth of the packet band. This is one way Synchrony ST reduces
the probability of traffic congestion. Rate enforcement occurs at PVC
endpoints.
34
(BITS)
ACCESS RATE
DISCARD
ALL FRAMES
Bc + Be
USER
ACTIVITY
FRAMES ELIGIBLE
FOR DISCARD
Bc
CIR
TIME
T0 + T
T0
MEASUREMENT
INTERVAL
USER
ACTIVITY
FRAME 1
COMPLIANT
FRAME 2
COMPLIANT
FRAME 3
EXCESS
FRAME 4
DISCARD
Figure 14. Packet Traffic Parameter Relationships
Rate enforcement, however, does not take into account the congestion
that may result from coincidental events such as peaks in demand. The
packet subnetwork establishes congestion measurements based on
queue lengths and multiple thresholds and then monitors them in real
time. Depending on the degree of the congestion observed, specific
actions are taken to counter the situation.
Two bits in the DLCI header are used to notify devices at connection
endpoints of congestion. The Forward Explicit Congestion
Notification (FECN) bit indicates whether the frame carrying it has
encountered congested resources while en route. This information is
useful for flow control at the destination. The Backward Explicit
Congestion Notification (BECN) bit indicates whether congestion
exists in the opposite direction of the frame carrying it. This
information is useful to adjust the rate of source-controlled
transmitters.
FECN
BECN
FRAME
TRAFFIC
35
Routing
Each ST network node stores a current version of the network
topology map and uses the information to determine source routing
the best available path for a connection across the network. The map is
automatically updated in regular intervals or is updated upon events
that result in added or removed nodes, changes in BER performance
and loading of each internodal link, or changes in node capabilities
(for example, whether or not a node is equipped with FSMs). With
this dynamic routing mechanism, manual routing tables are not
required.
When a CBR channel or PVC requires a connection, the source node
scans its topology data to determine a complete path to the destination.
Should this path fail for any reason, the source node receives an error
indication, updates its topology accordingly, and selects the next best
available complete path to the destination.
Least-Cost Routing
When a channel connection is required, the network uses a modified
Dijkstra algorithm to determine the least-cost path between two
endpoints. Routing is based on one of the following cost criteria listed
in Table 1.
Table 1. Cost Criteria
CBR Channel Cost Criteria
• Number of internodal hops
• A user-defined delay (per INL)
Frame Relay Channel Cost Criteria
• Number of internodal hops
• A user-defined delay (per INL)
• Sum of user-defined delay and
queuing delay at time of
connection
The network administrator defines the criteria used to select the best
path, and can specify rules in terms of INL quality, number of hops,
security (encrypted vs. nonencrypted INL), and trunk groups. For
example, the network administrator can specify whether a particular
INL is to be carried over a satellite link. This information is used in
conjunction with the facility characteristic channel parameter, which
ensures that delay-sensitive channels are carried over terrestrial INLs.
The network administrator can also specify whether a particular INL is
to be encrypted by external equipment. This information is used in
36
conjunction with the facility characteristic channel parameter, which
ensures that sensitive channels are carried over encrypted INLs.
INL trunk groups provide a mechanism to achieve diverse routing,
ensuring that mission-critical channels are routed over different INLs.
Each node uses the cost criteria and limits in conjunction with its
topology map to dynamically determine paths in response to
connection requests.
Any network is usually built with fault tolerance in mind. Several
paths are created among nodes to provide a backup path if one or more
paths fail. If a failure occurs in the ST network, channels are
automatically rerouted.
Error Monitoring
In addition to the least-cost routing, route selection is further qualified
by restricting the use of an INL if it has an unacceptable bit error rate
(BER). To determine the BER on an INL, ST nodes monitor the INL's
packet band to detect cyclic redundancy check (CRC) errors on the
band. Nodes broadcast current BER information to each other. If the
BER on an INL exceeds the BER threshold set by a particular channel
profile, channels that are seeking a route and have been assigned that
profile are precluded from using that INL. Synchrony ST finds a better
path.
If channel connections exist on an INL whose BER has degraded to an
unacceptable level, the connection is rerouted over an INL with a
more acceptable BER.
Network Synchronization
The network is synchronized by the distribution of reference timing
signals throughout the network. Nodal clocking can be derived from
independent or dependent clock sources, and can be backed up by a
slave holdover mode that continues to provide clocking if no clock
references are available. Network clocking deploys a hierarchical
master-slave synchronization arrangement whereby timing signals
flow from a master node to a number of slave nodes.
37
Nodal Clocking
The ST node can derive its timing from a variety of clock reference
sources, including:
q
q
Independent sources (from the same node)
•
Station clock 1 or 2 (RS-422 interface)
•
Digital transmission facility timing via port transmit clocks or port
receive independent clocks. Clocks from T1M, E1M, or SDM
input must be continuous and in multiples of 8 kHz.
•
Internal oscillator, only if no other independent clock reference
source is available. The oscillator supplies a clock source with
stratum 3 accuracy.
Port receive dependent sources (from another node)
The ST node is capable of switching between eight user-defined
clocking sources. Sources are prioritized in a clock fallback list; the
first one in the list is the first choice for nodal and facility timing.
When the node initializes, the Nodal Control Processor selects and
qualifies the highest priority source from the Clock Fallback List. This
process continues down the list until a successful qualification check
occurs. The qualified clock is selected and the Nodal Control
Processor continues to monitor the clock's quality.
Slave Holdover Mode
If the timing reference source degrades, the clocking subsystem of the
node goes into a slave holdover mode and temporarily takes over
control until another clocking source can be qualified. The specific
sequence of events is as follows:
38
1.
Circuit Check Phase: Verifies the phase locked loop (PLL) circuitry
and integrity of the clock qualifier
2.
Qualification Phase: Prequalifies a clock source candidate by checking
its operational status. The clock qualification circuit validates the
candidate's frequency. If the frequency falls within the tolerance range
defined by the clock quality parameter (either a deviation of 7 10 ppm
from nominal or a deviation of 7 48 ppm from nominal), the digital PLL
is directed to lock to that clock.
3.
Online Operation Phase: Compiles the history of the center frequency
values required to perform slave holdover mode
If a clock source fails during online operation, the ST node uses the
history of the previous clocking source to operate in slave holdover
mode. If a previously disqualified higher priority clock source comes
back online, the ST node supports preemptive switching to this
restored clock source.
Master Clocking Nodes
The ST network supports a multiple master (MM) clocking scheme of
up to 16 user-designated MM nodes. Each MM node must have access
to at least one independent clock source. MM nodes are prioritized in
the master clock list and a copy is provided to each MM node. All
other nodes are considered slave-clocking nodes and typically derive
timing from port receive connections.
The highest priority MM node is the active master for the network,
and uses only independent clock sources for its clock fallback. The
other master nodes use all entries in the clock fallback list.
Multiple masters ensure the following:
q
q
Each network segment is independently clocked by a single source.
A graceful recovery occurs if the primary active node fails.
In order for a connection to pass through multiple nodes without slips
or data hits, all relevant I/O ports, nodes, and INLs must be
synchronized to the same timing source.
39
Network Management
The Synchrony Network Management
System offers comprehensive management
of the Ascom Timeplex circuit-switching
and frame-switching system . . . .
xpressly designed to manage, monitor, and maintain your ST
network, the Synchrony Network Management System
(SNMS) is the latest Ascom Timeplex network management
product. Using the Simple Network Management Protocol (SNMP)
and the CA-Ingres relational database, SNMS offers comprehensive
management of the Ascom Timeplex circuit-switching/frameswitching system. Built on the HP OpenView network management
platform, SNMS provides visibility, control, and diagnostics for
backbone networks carrying circuit and frame traffic.
E
The Synchrony Network Management System runs under the
HP OpenView platform, the industry-leading platform in network
management software, for which there is a rich library of third-party
tools, utilities, and applications. This ever-growing library ensures a
wide range of customized networking solutions to suit your business
needs.
SNMS complements a solid foundation of network management tools
with additional applications and utilities specially designed to optimize
management and performance of the ST family of products.
The Synchrony Network Management System is a multitasking "pointand-click" application that uses the X Window System graphical user
interface. Based on X.11 and OSF/Motif, this environment is
compliant with the HP OpenView Style Guide. The X Window
41
Network Management
System provides a user-friendly interface that is highly intuitive and
easily mastered. As a result, your network management staff requires
less training to gain familiarity and becomes productive quickly.
Sun Microsystems workstations with the SPARC architecture are used
to operate the network management software. The workstation
connects to the ST network through an Ethernet (10BASE-T) port on
the Nodal Control Processor (NCP). Alternative access is also possible
through the modem port on the NCP. Table 2 summarizes the network
management system specifications.
Table 2. SNMS Specifications
Specification
Description
Hardware platform
Sun SPARCstation 5 model 110,
SPARCstation 20 model 71
Minimum disk drive requirements
Two 535-MB disk drives
Minimum RAM requirements
72 MB
Hardware accessories
3.5-inch floppy disk drive, monitor, CD-ROM
drive, 1/4-inch tape drive
Software requirements
SunOS 4.1.3c (Solaris 1.1 version C) or
SunOS 4.1.4, X Windows, Motif, CA-Ingres
RDBMS, HP OpenView Software Platform
version 3.3.1 or Network Node Manager 4.0,
Synchrony Network Management Software
SNMS can run concurrently with other Ascom Timeplex network
management systems, such as TIME/VIEW 2000, TIME/VIEW 2500,
and EMS 200. With coresident operation, you can reduce hardware
cost and have the convenience of a single workstation interface to both
local area network (LAN) and wide area network (WAN) devices.
This section discusses the configuration and diagnostic features of
SNMS, including:
q
q
q
q
q
q
42
Topology management
Node management
Alarm management
Fault management
Security
Information management
Network Management
Topology Management
SNMS is not only designed to leverage industry-standard platforms,
but it is also easy to use. This is illustrated by the software's automatic
features like network discovery and the network topology map.
Automatic Network Discovery
From the beginning, users are not burdened with time-consuming
administrative tasks such as loading their network topology into the
system. The Synchrony Network Management System takes care of
this automatically. Since the network management product uses
standard SNMP to communicate, topology is determined by locating
all SNMP-addressable network elements that have an associated
Internet Protocol (IP) address. Once IP addresses are recognized,
topology information is automatically uploaded and stored in the
database.
Network Topology Map
Using the information loaded during the discovery process, the
Synchrony Network Management System generates a detailed,
accurate, color-coded map of the network topology. As illustrated in
Figure 15, icons are used to represent ST nodes and IP devices (such
as workstations); lines are used to represent the network links between
them. The color of an icon or line indicates the operational status of
the network element it represents.
The topology is continuously updated and, if desired, the display can
be altered to show your own customized view of the network. An icon
representing the backbone network facilitates access to the ST nodes.
If the network is an integrated ST-LINK/+ hybrid network (via the
LINK/+ Gateway Module), SNMS also provides the capability of
displaying LINK/+ node icons and their associated interconnections as
shown in Figure 16.
The sample backbone network topology map in Figure 16 displays the
nodes (ST and LINK/+), the links between them, and other network
devices. A PBX Submap icon provides access to the private branch
exchanges connected to an ST node. An AD Submap icon provides
access to all of the AD-10, AD-7, and AD-3 devices connected to an
ST node.
43
Network Management
IP Internet
File Edit
Locate View
Options Monitor
Administer
Diagnose Misc
Help
IP
IP
134.196.7
134.196.203
IP
IP
IP
fddi_net
134.196.19
134.196.2
tl 470/1
134.196.11.4
IP
470_11_dev_net
ST
ST-20
Backbone Network Icon
ST-20 Node 20
IP
134.196.13
IP
ST-1000
192.42.62
ST-1000 Node 6
IP
134.196.15
default [Read-Write]
OPENVIEW
WINDOWS
IP Network View [Auto-Layout]
Close
Home
Root
HEWLETT
PACKARD
Parent
Figure 15. SNMS IP Topology Map
Backbone Network View
File Edit
Locate View
Options Monitor
Administer
Diagnose Misc
AD
Help
AD
AD Submap
ST INL
ST-1000
AD Submap
ST-1000 Node 6
ST-1000
ST-1000 Node 5
LINK 100 Node 9
PBX Submap
ST INL
LINK DL
AD
AD Submap
ST-20
ST-20 Node 20
ST INL
LGM DL
LINK 2 Node 2
ST-1000
ST-1000 Node 2000
LINK DL
LINK DL
PBX Submap
microLINK Node 3
default [Read-Write]
OPENVIEW
WINDOWS
Close
miniLINK Node 4
Backbone Network View [Auto-Layout]
Home
Root
Parent
HEWLETT
PACKARD
Figure 16. SNMS Backbone Network View Topology Map
44
Network Management
Node Management
While the network topology map shows the position of nodes and their
connections, the node management feature shows an accurate
graphical representation of the components of a selected ST node.
You can view the status of a particular ST node or module using
point-and-click commands. The icon expands to display the physical
chassis configuration, the status of all modules contained within it, and
the node's power supplies.
Configuration and modification of the network is easy. You can
perform the following:
q
q
q
Display the status and statistics for internodal links, nodes, modules, and
ports
Insert, configure, and delete nodes, shelves, modules, and ports
Configure alarms and filters
Internodal Link Management
Internodal links (INLs) connect ST nodes to form the ST network.
With the internodal link management feature, you can administer,
manage, and track the physical connections of your network. You can
display information about existing links including source address,
destination address, status, and INL type. You can also add, modify, or
delete INLs.
If the network is an ST-LINK/+ hybrid network integrated via the
LINK/+ Gateway Module (LGM), the INL management feature also
enables you to manage LINK/+ data links—the connections between
LINK/+ nodes. You can manage the LINK/+ data links just as you can
manage the ST internodal links. INL management also allows you to
administer, configure, and control LGM data links—the connections
between ST and LINK/+ nodes.
Bundle Management
The bundle management feature enables you to display the available
64-kbps streams and bundle parameters for a selected port. You can
also create new bundles, add or subtract data streams from existing
bundles, and display bundle status.
45
Network Management
Profile Management
The profile management feature provides network-wide support of ST
channel and voice profiles. A channel profile is a group of channel
parameters used for channel routing and connections. You assign each
channel a profile, but the profile does not have to be unique. With the
profile management feature you can create, modify, and delete channel
profiles.
A voice profile contains a list of voice processing parameters, such as
voice compression and echo cancellation, used for the transport of a
voice call between PBXs. The profile management feature allows you
to create, modify, and delete voice profiles.
Subrate and Superrate Channel
Management
With the Synchrony Network Management System, you can create,
modify, and delete subrate and superrate channels. A subrate channel
carries data at a rate below 56 kbps. A superrate channel carries data at
a speed that is a multiple of 56 or 64 kbps.
The channel management feature enables you to display existing
channel connections with source and destination addresses, connection
type, and status. You can also use this feature to connect, disconnect,
and reset subrate and superrate channels.
In an ST-LINK/+ hybrid network, the channel management feature
also provides full support for managing channels involving LINK/+
nodes. You can manage channels between LINK/+ nodes whether or
not the channels pass through an ST node. You can manage channels
originating at LINK/+ nodes and terminating at ST nodes, and you
you can manage channels originating at ST nodes and terminating at
LINK/+ nodes.
Voice Circuit Management
You can use compressed voice circuits to efficiently communicate
voice and fax data between ST nodes. With the voice circuit
management feature, you can create, modify, and delete trunk groups
and trunk circuits. Trunk groups are required to control voice
compression characteristics and to determine the destination of a set of
compressed voice circuits. Trunk circuits are the individual
46
Network Management
compressed voice circuits that make use of a trunk group circuit, the
connection between the source trunk group and the destination trunk
group. The voice circuit management feature also allows you to
connect, disconnect, and reset trunk circuits.
Frame Relay Management
Frame relay permanent virtual circuits (PVCs) are mapped out in the
network topology map along with the physical network links.
Information about existing frame relay connections is displayed,
including source and destination addresses, connection type, and
status. This information makes it easier for the network system
administrator to identify and resolve problems involving the
interaction between logical and physical networks.
With the frame relay management feature, you can create, modify, and
delete frame relay channels. You can also connect, disconnect, and
reset frame relay channels.
Network performance can be evaluated and optimized by gathering
detailed statistics at user-defined intervals for the frame relay circuits.
Statistics include the number of frames sent, received, and dropped.
You can also monitor CBR and packet bandwidth to determine how to
best utilize your network's transmission facilities.
Access Device Management
The Synchrony Network Management System provides support for
AD-10, AD-7, and AD-3 access devices. Access device management
is similar to node management. You can view the status of a particular
access device using point-and-click commands. You can insert,
configure, and delete access devices. Using the channel management
feature, you can configure channels with access devices as endpoints.
Routing Table Management
The Synchrony Network Management System provides the capability
to effectively manage the routing tables of LINK/+ nodes in an
ST-LINK/+ hybrid network. You can selectively upload or download
routing tables for one or more LINK/+ nodes. You can automatically
generate and download routing tables for all LINK/+ nodes. You can
also add, modify, and delete table entries for a selected LINK/+ node.
47
Network Management
Softload Upgradability
The Synchrony Network Management System offers an integrated
softload utility that can distribute the nodal operating software either
locally or from a central location. This method of upgrading software
is less time-consuming and more economical than other methods. The
utility uses the Trivial File Transfer Protocol (TFTP) to transfer the
desired load file to the selected node while it is still in operation.
There is no disruption of service. The software is verified by the
Nodal Control Processor and can then be activated at the user's
request.
Restoration of a node's configuration is simple because the softload
capability enables you to redistribute nodal operating software and a
backup of the Management Information Base (MIB) quickly and
efficiently.
Alarm Management
The integrated alarm management feature identifies an event or fault
in your ST wide area network as quickly as possible, regardless of its
source. This feature is tied to the topology map and uses color-coded
status to indicate the health of a node or subnetwork.
An ST network employs the SNMP standard method of trap-directed
polling to alert network management of problems. Each network
element (for example, a node) is responsible for notifying the
Synchrony Network Management System of all events. This makes
regular polling for status unnecessary and allows for more efficient
use of network resources.
Alarm notification messages are highly visible and centrally
monitored. Messages sent to root nodes include the node number of
the sender, the alarm log number, the highest outstanding severity for
the log, and an overflow notification. The Alarm Integrator is used to
retrieve the alarm message. Upon receipt, alarm information is
automatically stored in a history log, which ensures an accurate record
of all alarms.
Alarms can be customized at the node level to best suit your network
management needs. You can define alarm notification lists, filters, and
SNMP trap subscriptions. Filters can be based on the type of the
equipment, partition, and/or alarm severity.
48
Network Management
In an ST-LINK/+ hybrid network, the alarm management feature
provides support of both ST and LINK/+ alarms to be displayed in the
Alarm Integrator.
Fault Management
During normal operation you can monitor your network topology map
for color alerts, watch for changes in the front panel indicators, check
alarm messages, and, when necessary, perform diagnostics and
execute loopback commands.
Connection Diagnostics
To diagnose network problems quickly, you can trace INLs between
ST nodes and even circuits as a way of isolating network faults. With
the Synchrony Network Management System, it is easy to establish
loops and generate test patterns to pinpoint the problem. The
diagnostic management feature graphically represents loopbacks and
allows you to initiate them with simple point-and-click commands.
Figure 17 shows the representation of a circuit loopback.
CIRCUIT DIAGNOSTICS
BYPASS
NODES
Source
Destination
5:1:7:4:1:1
6:1:6:3:1:3
Tone
Generator
Tone
Generator
Bi-Directional
Bi-Directional
Test
Generator
Test
Generator
Test Generator Type
Local Remote
Test Generator Type
Local Remote
Update Status
Tone Info
Cancel
Help
INFORMATION
DISPLAY
COMMAND
BUTTONS
Figure 17. Circuit Loopback
49
Network Management
You can disable ST INLs without losing stored setup and
configuration parameters, and without disconnecting existing
channels.
Node Diagnostics
In addition to connection diagnostics, the fault management feature
also allows you to isolate problems in an ST node quickly, increasing
system availability and decreasing network downtime. Using this
feature, you can reset an entire node, selected shelf, or module. If you
are checking an expansion module, you can toggle between the
redundant circuits. You can troubleshoot right down to the port level
of I/O and server modules. Port diagnostic capabilities include
reinitializing, removal, or disabling. In addition, you can perform
loopback tests on a node, shelf, module, or port to determine the
source of a failure.
Security
The network administrator can restrict access of individuals based on a
wide range of parameters including log-in times, accessible partitions,
accessible applications, and activities performed. You can offer
network users access to the applications and information they need
while also keeping your network secure.
Network Partitioning Capabilities
The Synchrony Network Management System features partitioning, a
capability that allows a single network to provide for multiple users in
a secure and protected manner. This is accomplished by dividing your
ST network into logical partitions or virtual private networks (VPNs)
as illustrated in Figure 18.
Partitioning allows the service provider to accommodate the private
user while safely limiting the network connections the user can make.
Partitioning is equally useful in a private network setting and can be
based on geographic boundaries, operator expertise, or time of day for
management coverage.
Within partitions you can also define "communities" and use them to
create access profiles. Combinations of partitions and communities can
help manage user access to network equipment and resources.
50
Network Management
For example, you can create a partition containing nodes for a logical
entity, such as West Coast Distribution. The West Coast Distribution
partition would contain only those network nodes and resources that
are applicable to the operations of the West Coast Distribution group.
VPN CLIENT
(A, B)
GLOBAL VPN
SERVER
NEW YORK
SAN FRANCISCO
CHICAGO
WOODCLIFF LAKE
VPN CLIENT
(C)
LONDON
NEW YORK
SAN FRANCISCO
NEW YORK
SAN FRANCISCO
CHICAGO
WOODCLIFF LAKE
LONDON
LONDON
CHICAGO
WOODCLIFF LAKE
(X-TERMINAL)
VPN C
VPN A
ST-1000
ST-1000
VPN B
AD-7
AD-7
AD-7
AD-7
AD-3
AD-3
ST-20
Figure 18. Virtual Private Networks
Within the partition definition you could also create two communities:
administrator and operator. The administrator community could be
defined to have full access to change network resources, while the
operator community might only need read-only access to network
resources. You could then assign a network management user to the
West Coast Distribution partition and then to the administrator or
operator community within the partition.
You can use the Partition Editor and the Partition Element Editor to
manage network partitions.
51
Network Management
Information Management
Information management capabilities are available for collecting,
viewing, analyzing, and reporting on network performance. You can
quickly and easily gather detailed information on throughput, system
availability, down-time, alarm events, and more to optimize your
network and improve performance.
Relational Database
The Synchrony Network Management System uses the CA-Ingres
relational database, which is designed with an open architecture that
works with major industry-standard database, hardware, software, and
network protocols. The CA-Ingres database provides a wide array of
database management software tools to assist you in managing your
database.
Billing and Accounting
You can use information from the CA-Ingres database to create
customized billing reports and statements or to import the billing data
to a third-party accounting software package. By collecting and
reporting on network usage and performance, the Synchrony Network
Management System allows you to bill network users based on their
consumption of resources.
Craft Person Station (CPS)
The Craft Person Station (CPS) is a tool used for initial configuration
of an ST node and includes a comprehensive set of diagnostic
commands to verify communication links between network
components.
CPS is most useful for local diagnostics at the node. In addition, if a
node is not accessible from a network management workstation, CPS
can perform remote diagnostics and troubleshooting. When CPS polls
a node, it can alert you with alarms when there is a problem in the
node.
52
Network Management
CPS runs on an IBM PC, XT, AT, or compatible with the following
minimum requirements:
q
q
q
q
q
8088 processor
DOS 3.2 or higher
720 KB or higher disk drive (if using softload, 1.44 MB is required)
640 KB RAM
one serial port (must be COM1 or COM2)
53
Applications
. . . Synchrony ST consistently provides
superior networking solutions to popular
business environments and application trends.
ynchrony ST provides a highly flexible network capable of
handling a variety of applications. There are several reasons
for this including a well-balanced product family and the
diverse technologies and services that Synchrony ST offers.
S
Since many of the real-life application scenarios presented in this
section incorporate other products from Ascom Timeplex, the
following pages briefly describe those products. The scenarios that
follow illustrate the flexibility of Synchrony ST and show how Ascom
Timeplex consistently provides superior networking solutions to
popular business environments and application trends.
This section also includes an overview of the high-quality technical
support and customer service you can expect from a worldwide leader,
Ascom Timeplex. The services provided by Ascom Timeplex include
installation support, comprehensive educational and training services,
and dependable maintenance programs.
55
Applications
Other Ascom Timeplex
Products
This section provides an overview of other Ascom Timeplex products.
Many of these networking products are represented in the application
scenarios presented later.
Synchrony ER-5
A member of the Synchrony family, the ER-5 is a five-slot, highperformance, high-capacity router and frame relay switch for WAN
consolidation and backbone networking. The ER-5 provides
continuous availability via a 1.9-Gbps redundant bus, totally
distributed processing, hot swap, and redundant power. The Express
Switching architecture offers the appropriate qualities of service for
LAN or legacy traffic. The ER-5 also has downloadable software
support.
The ER-5 modules can be used in an ST-1000 node.
Synchrony NP-1000
A member of the Synchrony family, the NP-1000 is a high-capacity,
modular X.25 legacy switch and frame relay access device (FRAD)
that supports X.25, bisynchronous, Burroughs Poll, asynchronous, and
SDLC/HDLC protocols. The NP-1000 offers data compression,
encryption, and remote downloading as well as extensive IBM support
including multidrop, QLLC, and SDLC spoofing. The NP-1000
supports a range of interfaces and speeds up to 256 kbps.
Synchrony TX-3
A member of the Synchrony family, the TX-3 is a reliable and costeffective SONET OC-3, DS-3, and DS-1 transport system for
establishing OC-3 and DS-3 backbone networks in private or carrier
environments. Standard solutions for DS-3 transport, such as M13
multiplexers and manual or electronic patch panels, are surpassed by
the integrated and highly automated TX-3 design and functionality.
The TX-3 incorporates up to 720 Mbps of traffic-carrying capacity,
nonblocking cross-connect capabilities, multimegabit channel
56
Applications
provisioning up to 41 Mbps, and automatic alternate routing to protect
against network facility failures.
Router Bridge
The Router Bridge is a cost-effective, mid-range, 12-port router and
frame relay switch/FRAD that supports 4-Ethernet, Token Ring, Fiber
Distributed Data Interface (FDDI), and WAN. The Express Switching
architecture offers the appropriate qualities of service for LAN or
legacy traffic. Additionally, the Router Bridge offers downloadable
software and LAN Network Manager support.
Frame Server
The Frame Server is a cost-effective, mid-range, 12-port frame relay
switch/FRAD that is standards compliant. Additionally, the Frame
Server supports full routing and bridging for Ethernet, Token Ring,
and FDDI LANs.
LINK/+ Integrated Connectivity
Systems
The LINK/+ Family of Integrated Connectivity Systems are fullfeatured, high-performance networking multiplexers. LINK/+ Systems
deliver full integration for a total range of voice, data, and image
transmission over T-1/E-1/NTT or lower speed facilities. Fractional
T-1/E-1/NTT services, which provide substantial cost efficiencies over
networks with underutilized T-1/E-1/NTT or multiple DDS lines, are
also supported.
The LINK/2+ System supports large networks with heavy I/O
requirements. The LINK/100+ System is a high-capacity T-1/E-1
(North American/CCITT) transport system for large backbone
networks. Building on the LINK/2+ System, the LINK/100+ System
provides increased networking capacity and capability.
LINK/+ access systems include the miniLINK/2+ System for smaller,
stand-alone networks and a wide range of secondary and feeder
connections, the microLINK/2+ System for cost-effective extensions
of backbone networks, and the entréeLINK/+ System for edge-of-thenetwork applications.
57
Applications
Application Scenarios
This section describes and illustrates various networking applications
that you can implement with a Synchrony ST backbone. The
application scenarios presented include:
q
q
q
q
q
q
q
q
q
Traditional
Voice/packet hybrid
Frame relay switch
PBX networking
ST and LINK/+ integration via the LINK/+ Gateway Module (LGM)
ST and LINK/+ DS0/X.50 compatibility
Branch access
Campus
International
Although the scenarios are presented separately, you can mix and
match the services to produce the appropriate solution to your
company's needs.
Traditional Application
A traditional backbone network, as illustrated in Figure 19, supports a
mix of voice and data traffic among corporate locations that require
high-capacity digital facilities. Until now, these networks have been
built using standards-based channel banks or flexible-framedyet
proprietaryTDM multiplexers.
58
Applications
FRONT-END
PROCESSOR
HOST DATA
• SDLC
ST-1000
ST-1000
E1/T1
PBX DIGITAL
• FAX
• VOICE
VIDEO
PBX DIGITAL
• FAX
• VOICE
VIDEO
/T1
E1
E1
/T1
ETHERNET
NEW YORK
SAN FRANCISCO
CHICAGO
WOODCLIFF LAKE
LONDON
ST-20
NETWORK
MANAGEMENT
WORKSTATION
VIDEO
FRONT-END
PROCESSOR
PBX
DIGITAL
Figure 19. TDM Private Network
Representing a new era of switching and transport systems,
Synchrony ST delivers standards-based networking, offers an easy
interface to carrier facilities, and provides advanced bandwidth
efficiency capable of carrying a variety of voice and video data.
Unlike previous channel bank solutions, ST rapidly restores circuit
connections after a facility outage and dynamically routes channels
across the network.
Typical TDM applications benefit from such a backbone because they
are guaranteed bandwidth and fixed latency. TDM is the only
technology available today that can make that 100-percent guarantee.
59
Applications
Voice/Packet Hybrid Application
Although voice will remain a major component of communications
networks, the traffic mix is including more packet-based, bursty
applications. One way to maximize bandwidth efficiency for bursty
traffic transport is to statistically multiplex packets into an aggregate
protocol. However, it would be impractical to convert all applications
to packet-oriented platforms. As a result, a TDM-packet hybrid on a
single platform, like the one illustrated in Figure 20, is a winning
combination.
PBX
ST-20
AR
PBX
ST-1000
PBX
ST-1000
AR
ETHERNET
NETWORK
MANAGEMENT
WORKSTATION
NEW YORK
SAN FRANCISCO
CHICAGO
WOODCLIFF LAKE
LONDON
Figure 20. Voice/Packet Hybrid Network
60
Applications
LAN traffic (from routers, bridges, gateways, and other LAN/WAN
devices) is typically bursty and requires high bandwidth for
“acceptable” transport. The challenge is to accommodate bursty traffic
without having to reserve high bandwidth exclusively. Synchrony ST
meets this challenge by dynamically allocating bandwidth as needed.
Similarly, voice traffic requires dedicated bandwidth for the duration
of the conversation. After the PBX goes “on-hook,” that bandwidth is
released for other voice calls or applications. The ST hybrid
architecture releases voice bandwidth after the tie-line is disconnected
and returns the bandwidth, in 64-kbps increments, to the frame or
packet bandwidth pool.
Frame Relay Switch Application
Frame relay is currently the telecommunication industry’s hottest
technology for high-speed packet networking. As a wide area protocol,
frame relay incorporates the delivery efficiency of X.25 with its
multiple virtual circuits over a single interface while eliminating the
relatively high overhead of robust protocols like X.25.
As illustrated in Figure 21, Synchrony ST provides a high-capacity,
frame-switching infrastructure that allows a multitude of frame relay
devices to interwork. With channelized interfaces, ST cost-effectively
accesses carrier leased-line services to build pure private frame relay
networks or pure public frame relay access networks.
Synchrony ST switches frame-based data through the network. If the
frame device has a standard ITU-T I.122 or ANSI T1.606-based
interface, ST can deliver data traveling on multiple virtual circuits to
multiple destinations. For efficiency, ST segments longer incoming
frames into short 256-byte packets, which are then reassembled at the
destination.
Additionally, ST supports the Frame Relay Forum’s Network-toNetwork Interface (NNI) standard, which allows an ST node to
gateway into another vendor’s network.
61
Applications
ST-1000
FRAD
BNP-350
ST-1000
FRAD
AR-350
BNP-350
AR-350
ETHERNET
ST-1000
FRAD
NEW YORK
SAN FRANCISCO
CHICAGO
WOODCLIFF LAKE
LONDON
NETWORK
MANAGEMENT
WORKSTATION
BNP-350
AR-350
Figure 21. Private Frame Relay Network
PBX Networking Application
PBX networking uses the DPNSS or QSIG common channel signaling
(CCS) protocol to significantly improve bandwidth efficiency and
flexibility when managing voice traffic among multiple PBXs. As
illustrated in Figure 22, PBXs can be interconnected with an ST node
to allocate bandwidth when voice calls are set up. Using local and
remote exchange routing tables, ST can route any call based on the
digits dialed. PBX networking provides distance-based quality of
service (for example, PCM for local connections and compressed calls
for remote connections) and call-type quality of service (for example,
64 kbps for clear channel data calls).
PBX networking is implemented by the D-Channel Server Module
(DSM), which communicates with a PBX via the D-channel (a 64kbps time slot of a T1M or E1M I/O port). The DSM interprets the
D-channel messages for connection origination and termination. Based
on received connection messages, the DSM can route calls to a local
or remote PBX. The DSM also transports supplementary service
messages from PBX to PBX, allowing effective use of advanced PBX
services such as call diversion, call waiting, and call conferencing.
62
Applications
PBX
PBX
ST-1000
ST-1000
LOCAL EXCHANGE ROUTING TABLE
1714
9682
1813
5639
REMOTE EXCHANGE ROUTING TABLE
1404
1813
1415
3267
5639
8432
1415
1714
1404
9682
3267
8432
DSM
NETWORK
PBX
PBX
ST-1000
ST-1000
1415
3267
1404
8432
1813
1714
1404
9682
5639
8432
1714
1415
1813
9682
3267
5639
Figure 22. PBX Networking
PBX networking provides several benefits:
q
q
q
q
q
q
Addresses the problems associated with compressed tandem
calls—problems such as the degradation of voice quality
Allows ST to route any call based on the digits dialed
Provides distance-based and call-type quality of service
Can transport PCM or compressed voice
Takes advantage of the breathing bandwidth on ST internodal links to
support contention mode for PBXs using common channel signaling
protocols
Reduces the total number of PBX interfaces required
63
Applications
ST and LINK/+ Gateway Application
The LINK/+ Gateway Module (LGM) provides the solution for
achieving an integrated ST and LINK/+ hybrid network as illustrated
in Figure 23. While logically terminating a LINK/+ proprietary data
link—the ILC aggregate format (IAF) stream—the LGM
demultiplexes the IAF and reformats the LINK/+ data (which includes
I/O channel data and supervisory/control information) into ST format.
The reformatted data can then be transmitted through the ST network
or teminate at an ST node. The LGM can also reformat ST data into
LINK/+ data for transmission to a LINK/+ node.
NEW YORK
SAN FRANCISCO
CHICAGO
WOODCLIFF LAKE
LONDON
SERIAL
ASYNC
NETWORK
MANAGEMENT
WORKSTATION
ETHERNET
LINK/2+
ST-1000
VIDEO
ILC
P
B
X
VIDEO
ILC
N X 64 KBPS
CIRCUITS
N X 64 KBPS
CIRCUITS
LINK/2+
LINK/2+
ST-1000
P
B
X
PACKET
PACKET
AR-350
AR-350
TERMINAL
LINK/2+
ST-1000
ILC
COMPUTER
N X 64 KBPS
CIRCUITS
PACKET
AR-350
Figure 23. ST and LINK/+ Integrated Hybrid Network
Designed to enable existing LINK/+ customers to maintain the
investment in their existing infrastructure, the LGM allows the
customer to take advantage of ST features and benefits. ST nodes can
be added to expand an existing LINK/+ network, providing the
network with the additional capabilities—such as frame relay and
ATM migration—offered by ST.
64
Applications
ST and LINK/+ DS0/X.50
Interworking Application
Interworking between ST and LINK/+ networks, as illustrated in
Figure 24, is accomplished via N x 64 kbps circuits (through the ST
backbone) and X.50 subrate channels (through a combination of the
LINK/+ X.50 Server Module and the ST subrate subnetwork).
LINK/2+ channels pass through and terminate on an ST node.
Additionally, LINK/+ channels can pass straight through an ST node
without any demultiplexing, provided the appropriate channelized
module is inserted in the LINK/2+ System.
NEW YORK
SAN FRANCISCO
CHICAGO
WOODCLIFF LAKE
LONDON
SERIAL
ASYNC
ETHERNET
LINK/2+
SUBRATE
NETWORK
MANAGEMENT
WORKSTATION
ST-1000
LINK/2+
ST-1000
X.50
DS0
N X 64 KBPS
N X 64 KBPS
CIRCUITS
N X 64 KBPS
CIRCUITS
PACKET
PACKET
AR-350
AR-350
ST-1000
LINK/2+
X.50
SUBRATE
N X 64 KBPS
DS0
N X 64 KBPS
CIRCUITS
PACKET
AR-350
Figure 24. ST and LINK/+ DS0/X.50 Interworking Network
In this way, existing LINK/+ customers can add Synchrony ST to their
environment without discarding their existing investment. ST can
support the new emerging applications, and LINK/+ can continue to
serve the customer with the legacy applications. And, network
synergies between LINK/+ and ST can be realized with the addition of
the LINK/+ Gateway Module.
65
Applications
Branch Access Application
The branch network is the most popular application for Synchrony ST.
Generally, for tariff reasons, it is inefficient to “home run” all the
leased lines to the branches back to the central site. Regional
concentration sites are built to minimize local access and transport
area (LATA) crossings and reduce overall leased-line expenses.
As illustrated in Figure 25, a mix of IANs and AD-10 access devices
populate the branches. The IAN integrates LAN and legacy
applications over a single access line while the AD-10 integrates
frame-oriented (HDLC) data and low bit-rate voice over a single
56/64-kbps access facility.
ST allows LAN, legacy, and frame traffic to travel over virtual circuits
rather than fixed bandwidth channels while simultaneously providing
highly reliable TDM channel connections for voice circuits.
802.5
802.3
OR
ETHERNET
LAN
PBX
PBX
ST-1000
IAN
ETHERNET
ST-20
NEW YORK
SAN FRANCISCO
CHICAGO
WOODCLIFF LAKE
LONDON
IAN
PUBLIC
NETWORK
NETWORK
MANAGEMENT
WORKSTATION
AD-10
PBX
AD-10
ST-1000
IAN
•ANALOG
•TERMINALS
PUBLIC
NETWORK
IAN
AD-10
AD-10
Figure 25. Branch Network
66
Applications
Campus Application
Synchrony ST was designed with more than just WAN networking in
mind. In a campus environment, ST offers the ability to use existing
installed copper to provision two-wire access several kilometers from
the ST node. Using the 2B1Q encoding scheme, up to six data circuits
can be extended up to 5 kilometers over a two-wire interface. In
addition, by using inexpensive T1 line drivers, the hybrid frame/TDM
network benefits can be realized in this environment. Figure 26
illustrates a typical campus network.
NETWORK MANAGEMENT
WORKSTATION
ETHERNET
HOST
AD-3
AD-7
AD-3
AD-3
ST-1000
AD-3
AD-7
ST-1000
AD-3
AD-7
AD-3
TERMINAL
AD-3
PRINTER
AD-3
AD-3
AD-3
AD-7
ST-1000
AD-3
AD-3
= 2B1Q PROTOCOL
AD-3
AD-7
AD-7
AD-7
Figure 26. Campus/Metropolitan Network
67
Applications
International Gateway Application
For multinational networks, Synchrony ST nodes terminate or switch
traffic between T1 and E1 facilities. As an added benefit, ST reduces
equipment requirements at international gateway locations.
Competitors' solutions require back-to-back T1 and E1 versions of the
equipment. Also, when digital voice channels traverse the
multinational network, they need to be delivered at each end with a
slightly different encoding scheme (for PCM voice). The ST node
converts from A-law to µ-law, depending on the interface type for the
voice channel. Figure 27 illustrates an international network.
NEW YORK
SAN FRANCISCO
CHICAGO
WOODCLIFF LAKE
LONDON
NETWORK
MANAGEMENT
WORKSTATION
PBX
A-LAW
ST-1000
E1
ETHERNET
PBX
µ-LAW
AR
/T1
E1
T1
VIDEO
ST-1000
AR
E1
VIDEO
E1
PBX
/T
1
ST-1000
E1
AR
VIDEO
Figure 27. International Network
68
Applications
Customer Support
Ascom Timeplex worldwide customer support provides a broad range
of service and support programs to install, maintain, and manage even
the most complex enterprise networks anywhere in the world. In
addition to installation and maintenance, the organization offers
training and professional services to ensure that your network is
always running at optimal levels.
Installation
From the time you place a product order and right through product
acceptance, Ascom Timeplex offers complete installation support for
all products. You can acquire additional installation services
separately, including complete network implementation, multivendor
pre-installation planning and support, and integration support.
Customer Support Center
The Ascom Timeplex Customer Support Center represents the first
level of support for Synchrony products. The center operates 24 hours
a day, seven days a week and offers an efficient, team-oriented
approach to network problem solving and troubleshooting. The
qualified Customer Support staff possesses an intimate knowledge of
Ascom Timeplex products and has a broad understanding of
communications networks. Customer Support also has, at its
fingertips, a database of supported Ascom Timeplex customer
networks.
Unlike other technical support organizations, Ascom Timeplex
Customer Support does not transfer a difficult problem from one team
to another. Instead, the existing team is augmented by the addition of
appropriate in-house experts. The representative who initially fields
the call continues to coordinate the effort.
The center is fully equipped with all Ascom Timeplex products and a
variety of diagnostic tools. Personnel can readily duplicate a network
configuration and then simulate a particular problem. In addition, the
center offers remote dial-up testing into a customer's network.
69
Applications
If a local service representative is dispatched to your site, the center
supports the coordination of this effort. The center pinpoints the
arrival time and representatives always come prepared with
appropriate diagnostic testing equipment and spare parts.
Maintenance
You can safeguard against network downtime by enrolling in one of
the Ascom Timeplex Contracted Period Maintenance Programs.
Choose round-the-clock coverage or standard business-hour coverage.
Supplemental services and alternative plans are also available to help
tailor maintenance support to meet your distinct needs.
Training and Education
Participation in the Network Assurance Training Program promotes
total network responsibility within your organization. This program
includes basic and advanced product operations training, network
staging, and on-site support to ensure a smooth transition from staging
through system installation.
Ascom Timeplex also offers a comprehensive curriculum of technical
courses. It is also possible to arrange customized courses designed to
meet your specific needs.
70
Product Overview
The right combination of customized Synchrony
components can create an integrated WAN
to satisfy even the most sophisticated demands
placed on businesses . . . .
T
he ST series of switching and transport nodes and the
Synchrony advanced access systems are the principal building
blocks of an ST network.
ST nodes comprise the backbone infrastructure and are available in
two models:
q
q
ST-1000
ST-20
Synchrony advanced access systems handle edge-of-the-network
connectivity and include the following groups:
q
q
q
q
AD, comprised of the AD-10, AD-7, and AD-3
AR, comprised of the AR-350, AR, and AR-150
BNP, comprised of the BNP-350 and BNP
IAN, comprised of the IAN and IAN-150
71
Product Overview
Synchrony equipment exploits the latest in silicon and manufacturing
technology to deliver the most dependable, economic systems
conceivable. CMOS (chips) technology in Very Large-Scale
Integration (VLSI) provides a small footprint and a cool-running
system. Surface Mount Device (SMD) technology in manufacturing
further reduces the system footprint and expense.
The right combination of customized Synchrony components can
create an integrated WAN to satisfy even the most sophisticated
demands placed on businesses in today's ever-changing
telecommunications environment.
An ST network is flexible enough to interwork with other Ascom
Timeplex products. A special ST modulethe LINK/+ Gateway
Moduledelivers LINK/+ and ST interoperability at the channel
level.
INTEROPERABILITY
Compliance with major industry standards from ANSI, ITU-T, and the
Frame Relay Forum for frame relay; ITU-T, CEPT, and Bellcore
standards for interfaces; and ETSI standards for physical packaging
also ensures interoperability between Synchrony systems and foreign
vendor products and carrier services.
Also, management of Synchrony WANs and LANs is all inclusive
with the Synchrony Network Management System. Built on an openended, industry-leading software platformOpenView from HewlettPackardthe network management system amply supports all
standard network management features plus ST-specific ones.
Switching and Transport Nodes
ST switching and transport nodes provide a unique blend of time
division multiplexing (TDM) and frame switching. This integration,
categorized as a hybrid design, eliminates the need for costly and
complex parallel networks.
72
Product Overview
The ST series has the following characteristics:
q
q
q
q
q
q
q
q
q
Handles voice and TDM using circuit connections and processes packets
through frame relay
Supports a format mix of HDLC and frame relay as well as traditional
TDM channels over framed and unframed facilities operating at
multiples of 56- and 64-kbps rates
Switches on standard 64-kbps boundaries
Establishes cross connections between I/O, I/O and servers, I/O and
trunks, and servers and trunks
Employs a modular, server-based architecture that allows the system to
take advantage of new services or reduced tariffs as they become
available without the need to install additional or expensive access
facilities
Allows termination of up to 31 internodal facilities and up to 480 local
user I/O ports operating at subrates (less than 56 kbps) and superrates
(greater than 64 kbps and up to 2.048 Mbps). (A maximum of 480 ports
is achieved when an ST node is configured with sixty 8-port SDMs.)
Can connect with Synchrony advanced access systems such as the ADs,
which are low-end access devices (data and compressed voice)
Allows for the creation of virtual private networks (VPNs) by means of
network partitioning
Provides integral router support and direct connections to Ethernet,
Token Ring, and FDDI local area networks (ST-1000 only)
The ST-1000 Node
The ST-1000 is a circuit-based networking multiplexer, a frame relay
switch, and a high-performance router/bridge combined in a single
unit. As a multiplexer and switch, the I/O modules in the unit are
designed to efficiently handle N x 64 kbps TDM and packet channels
simultaneously. As a router/bridge, the ST-1000 offers direct
connections to Ethernet, Token Ring, and FDDI local area networks
by accommodating internetworking modules.
73
Product Overview
The ST-1000 features Motorola and Intel processors. The Motorola
680x0 series of CPUs and the Intel i960 series of RISC CPUs are
implemented in the node's processing architecture to guarantee system
speed, performance, flexibility, and expandability. Figure 28
illustrates an ST-1000 with a view of the control shelf, equipped with
modules, and one expansion shelf.
FAN
ASSEMBLY
PS OK
PS OK
PS OK
PS OK
MODULES
POWER
SUPPLIES
CONTROL
SHELF
EXPANSION
SHELF
Figure 28. ST-1000 with Top Door Opened
74
Product Overview
Modular Architecture
The ST-1000 is architecturally modular and can be scaled to satisfy
the evolving applications and capacity requirements of your business.
To provide bandwidth manager frame-switching and circuit-switching
capabilities, the ST-1000 accommodates common equipment, I/O, and
server modules. To provide routing and bridging capabilities, the ST1000 accommodates internetworking modules. Table 3 identifies the
four types of ST-1000 modules.
For more information about
modules, see "Modular Node
Design" starting on page 99.
Table 3. ST-1000 Modules
Type
Common
Equipment
I/O
Server
Internetworking
Module
Nodal Control
Processor (NCP)
Right Expansion
Module (RXM)
Left Expansion Module
(LXM)
T1 Module (T1M)
E1 Module (E1M)
Synchronous Data
Module (SDM)
Remote Termination
Module (RTM)
Frame Server Module
(FSM)
Subrate Groomer
Module (SGM)
Application Server
Module (ASM)
D-Channel Server
Module (DSM)
LINK/+ Gateway
Module (LGM)
IEEE 802.3/Ethernet II
IEEE802.5/Token Ring
Fiber Distributed Data
Interface (FDDI)
Serial V.35
Serial V.11 (X.21)/Mil
188 (RS-449)
ISDN/BRI
High Speed Serial
Interface (HSSI)
Multi-Interface WAN
(MIW)
ATM Independent Cell
Processor (ICP)
Description
Control processing, terminate or
expand the bus backplane
Physically interface to the network
Perform specific functions or data
transformations that can be shared
across I/O modules
Provide local area network (LAN)
routing and bridging support,
transport LAN traffic via wide area
network (WAN) facilities
75
Product Overview
With Synchrony ST, it's easy to amass desired switching and transport
capabilities by combining appropriate modules for the nodes in your
network. Choose from I/O modules that provide interface ports for T1
or E1 carrier facilities or for superrate or subrate transmissions. Select
server modules to tailor the ST-1000 to match suitable switching
technology to the applications you need to support and the carrier/PTT
services you use. Because I/O interfaces and server modules are
completely independent of one another, the node is able to costeffectively channel processed traffic from one or more servers to one
or more interface ports.
In addition, the ST-1000 can be equipped at any time with
internetworking modules to provide direct LAN access. The
appropriate module allows direction connection to Ethernet, Token
Ring, or FDDI LANs. LAN protocols can be moved across the
network without the need to add additional external routers. A broad
range of wide area protocols and network services lets you choose the
services offering the best price/performance for your specific needs.
Bus Backplane
The ST-1000 backplane has a dual-bus design: a 160-Mbps bus that
accepts the bandwidth manager modules (common equipment, I/O,
and server) and a 1.9-Gbps bus that accepts the internetworking
modules.
The bandwidth manager bus is a unidirectional 160-Mbps looped
circuit bus that provides synchronous cross-connect capabilities for
N x 64 kbps channels with a bidirectional 77.5-Mbps maximum user
capacity. The bus architecture ensures that all server modules have
direct access to the entire bandwidth. Faster switching is achieved by
eliminating the need to traverse server modules to find assigned
bandwidth. Flexible transmission paths deliver traffic among directly
terminated data and voice interfaces, trunk interfaces, and server
modules.
The unidirectional circuit bus transports 2,500 64-kbps time slots,
which are accessed by I/O and server modules to write data to the bus
and read data from the bus. Time-slot assignments are established
when a module is installed and configured in the node. A virtual
packet bus embedded in the circuit bus creates a frame-switching
engine. Frame Server Modules (FSMs) connect to this packet bus and
76
Product Overview
enable packet traffic to be allocated bandwidth and carried on the bus
in packet bands. All packet modules can access any packet band.
At 1.9 Gbps, the high-speed internetworking bus operates at two to
three times the bus speed of "high-performance" routers.
Chassis and Shelving
The ST-1000 node consists of one control shelf and up to three
optional expansion shelves located in one or more physical chassis.
Expansion shelves can be added at any time to increase the number of
slots in the node. The maximum shelf capacity (one control and three
expansion shelves) permits 60 user modules per node. Shelves are
designed to be installed in a standard 19-inch or 24-inch equipment
cabinet or rack.
Control and expansion shelves each contain 17 slots. See Figure 28,
which illustrates a fully loaded control shelf and one expansion shelf.
When configured to provide bandwidth manager functions, the control
shelf of the ST-1000 uses the first slot for the Nodal Control Processor
and the last slot for the Right Expansion Module. If redundancy is
desired, the control shelf uses the second slot for the redundant Nodal
Control Processor.
When configured to provide router functions, the ST-1000 control
shelf always contains at least one internetworking module with a bus
arbitration daughterboard attached. Internetworking modules, also
commonly referred to as independent routing processors (IRPs),
cannot be installed in slots 8 and 9. If only one IRP module is
installed, it must be in slot 7 or 10. If more IRP modules are installed,
they should occupy slots 7 and 10 before occupying other available
slots. A bus arbitration daughterboard must be installed on an IRP in
either slot 7 or slot 10. To provide redundancy of this function, a bus
arbitration daughterboard can be installed on IRPs in both slots 7 and
10. Arbitration daughterboards on IRPs in other slots have no effect.
Expansion shelves use the first slot for the Left Expansion Module and
the last slot for the Right Expansion Module. See Figure 29, which is a
diagram of the logical shelf configuration of an ST-1000 that uses
expansion shelves.
77
Product Overview
MAIN SHELF
N
C
P
N
C
P
EXPANSION SHELF 2
R
X
M
EXPANSION SHELF 1
L
X
M
L
X
M
R
X
M
EXPANSION SHELF 3
R
X
M
L
X
M
R
X
M
Figure 29. ST-1000 Control and Optional Expansion Shelves
Each ST-1000 shelf is self-contained with its own power and fan
exhaust systems, allowing shelves to be mounted in open racks
without concern for electromagnetic interference (EMI) or cooling.
Modular distribution panels can be mounted in the front or back of the
same rack or cabinet, or they can be located remotely.
A fan chassis at the top of the shelf cools the shelf and modules. The
four fans in the fan chassis operate independently, providing
redundant cooling. Each fan is current protected and any fan failure
signals an alarm. The fan assembly is replaceable as a unit without
powering down the ST-1000.
An ST-1000 node can be arranged in one or more cabinets or in open
racks.
Power Distribution
The power distribution area is part of the system chassis and can be
configured in different ways depending on whether its input power
source is single AC, dual AC, or DC.
In a single AC input power system as shown in Figure 28, up to four
power supplies can be installed in a shelf in a load-sharing fashion.
One to three active power supplies are required to operate the modules
in the shelf, depending on the types and quantities of modules
installed. A fourth power supply is used to provide N + 1 redundancy.
78
Product Overview
A power entry unit (one per shelf), which plugs into the power
distribution backplane, distributes AC power from the input power
cord to the power distribution backplane. The power distribution
backplane distributes the AC power to the power supplies, which are
connected to a bus bar. Power for the ST-1000 modules is delivered to
the system backplane through the bus bar. The power entry unit
contains a circuit breaker to protect against over current.
In a dual AC input power system, up to eight load-sharing power
supplies can be installed in a shelf: four in an upper power supply bay
and four in a lower power supply bay. Power to the system is
connected via two power entry units. Each power entry unit distributes
the AC power from one of two independent power cords to its
appropriate power supply bay. The distribution of AC power in each
of the power supply bays and connection of the power supplies to the
ST-1000 modules is the same as in a single AC input power system.
When configured with a DC input power source, up to four DC power
supplies can be installed in a shelf. A DC power entry unit distributes
DC power from one or two independent power cords to the power
supplies. The distribution of the DC power lines to the power supplies
and connection of the power supplies to the ST-1000 modules is the
same as in a single AC input power system.
The ST-1000 is available with 115 VAC, 230 VAC, or -48 VDC
power supplies. Power supplies operate in parallel and can be changed
without powering down.
Cabling
Bulk cable connections on the faceplate of the individual I/O modules
optionally terminate on distribution panels that provide appropriate
interface connectors to other equipment and facilities. The distribution
panels may be located in the same rack or cabinet as the node or in a
separate rack.
79
Product Overview
The ST-20 Node
The ST-20 is a circuit-based networking multiplexer and frame relay
switch designed to efficiently handle N x 64 kbps TDM and packet
channels simultaneously. Mounted within standard racks or cabinets,
the ST-20 is a single-shelf unit, self-contained with its own power
supply and fan exhaust system as illustrated in Figure 30.
FAN
ASSEMBLY
POWER
SUPPLIES
SHELF
MODULES
Figure 30. ST-20 with Front Door Open
The ST-20 is almost functionally identical to the bandwidth manager
functionality of the ST-1000. The ST-20 employs the same modular
hardware design as the ST-1000 and uses virtually the same bandwidth
manager modules except for the RXM and LXM. Instead of the RXM,
the ST-20 uses the NCP to provide the bus loopback functionality of
the RXM. Left expansion is not applicable. Internetworking modules
cannot reside in the ST-20.
The ST-20 bus architecture is functionally very similar to that of the
bandwidth manager bus of the ST-1000. The ST-20 has a maximum
backplane throughput of 160 Mbps. Because the ST-20 is a singleshelf unit, the backplane cannot be extended across four shelves as it
can with the bandwidth manager bus of the ST-1000.
80
Product Overview
The ST-20 shelf has 12 slots. The first slot is reserved for the NCP;
the remaining 11 slots are available for insertion of I/O and server
modules. The second slot can also be used for a redundant NCP.
The power supply area holds two modular power supplies, each
capable of powering a fully provisioned ST-20 shelf, providing 1 + 1
redundancy. The power supplies operate in parallel and can be
changed without powering down. If each power supply is powered by
an independent power source, dual AC operation is provided.
Unlike the ST-1000, ST-20 power supplies are mounted laterally to
the module slots as shown in Figure 30. Power supplies are not
interchangeable between the ST-20 and the ST-1000.
Advanced Access Systems
Synchrony advanced access systems meet the diverse requirements of
branch networking. The systems cost-effectively deliver edge-of-thenetwork traffic to the ST backbone node. Access systems include the
following groups:
q
q
q
q
The AD group, which provides data and voice branch access devices
incorporating data handling and circuit switching. Includes remote
termination units designed to operate with ST networks and provide a
cost-effective means to extend channel access to low-density sites
The AR group, which provides efficient, cost-effective, and reliable
LAN internetworking solutions with control for remote sites, small sites,
or branch locations
The BNP group, which provides branch access systems that can perform
frame relay access and X.25 switching
The IAN group, which provides branch data networking systems that
incorporate access concentration, network-layer routing, and frame and
packet switching. Consolidates LAN and legacy traffic onto a single
wide area network
A discussion of the AD systems is presented below followed by a brief
overview of the AR, BNP, and IAN systems.
81
Product Overview
Synchrony AD
AD systems are time division multiplexers that allow multiple signals
data, voice, fax, and videoto be transmitted simultaneously over
single digital communications circuits. Designed to extend I/O
capacity of an ST node, the ADs offer an inexpensive way to transport
data and compressed voice from the edges of the network to the
backbone. The ADs interface with ST nodes and therefore are not
considered nodes within the network.
Three models are available to meet the communications requirements
of branch and remote sites. Models include the AD-10, AD-7, and
AD-3. The number of data ports on each device ranges from 2 to 16.
The ADs enable network administrators to implement the right
solution at each location and characteristically provide more
economical connection to ST switching nodes than the alternative of
running T1/E1 lines or using Channel Service Units (CSUs) and Data
Service Units (DSUs).
The AD-10 can be remote from the backbone node and use available
public network services (private or dedicated lines) to access the
private network. To serve a growing campus or metropolitan area
network, the AD-3 or AD-7 supports two-wire connections, using
existing copper-wiring plants.
The AD-10, AD-7, and AD-3 differ in packet capability, voice
capability, and the number of I/O ports. Table 4 compares the primary
features of the AD series.
You can configure, manage, and control the AD-10, AD-7, and AD-3
via the Synchrony Network Management System. The ADs can also be
configured from a terminal connected to their supervisory port.
82
Product Overview
Table 4. Synchrony AD Comparison Chart
Feature
AD-10
AD-7
AD-3
TDM multiplexing of
asynchronous data
No
Yes
Yes
Statistical multiplexing of
asynchronous data
Yes
No
No
Synchronous data
Yes
Yes
Yes
HDLC data
Yes
No
No
bisynchronous data
Yes
No
No
Voice processing
Yes
No
No
Port interface formats
V.24, V.35,
RS-449
X.21, V.24,
V.35
X.21, V.24,
V.35
Network interface formats
V.35, RS-449,
19.2/64 kbps,
56/64 kbps
2B1Q
2B1Q
Maximum number of I/O
ports
8 compressed
voice and 16
data ports
6
2
AD-10
The AD-10 is a TDM and packet-mode multiplexer that concentrates
voice, TDM, and packet data streams for input to an ST node. A single
ST node can support up to 256 AD-10 multiplexers.
Features include voice compression, intelligent data handling,
dynamic bandwidth allocation between voice and packet data, and
subrate data multiplexing for greater efficiencies on private leased
lines. The unit can support a maximum of 8 analog voice channels and
up to 16 data channels.
The AD-10 is used for point-to-ST network applications and creates
significant savings on voice, data, and fax traffic between remote sites.
For example, the AD-10 can connect branch offices or manufacturing
sites and distribution centers. ST routes the AD-10 subrate and packet
channels through the various ST subnetworks. The AD-10 subrate
TDM channels are routed through the ST subrate network, and the
AD-10 packet channels are routed through the ST packet subnetwork.
Once the AD-10 channels are demultiplexed, they are treated as any
channels originating from the ST node for routing purposes. In
addition, the AD-10 supports compressed voice down to 5.33 kbps
that is then routed through the subrate subnetwork.
83
Product Overview
The AD-10 is the most intelligent of the AD series. For applications
not requiring a great number of ports or the full functionality of the
AD-10, less expensive access devices such as the AD-7 and AD-3 can
be used.
Modular Architecture
The modular design of the AD-10 provides a flexible, open-ended
architecture to efficiently accommodate multiple voice, data, and
network interface options in a compact chassis. A single AD-10 comes
equipped with a core module and can support one Hybrid Data
Module (HDM), up to three Expansion Data Modules (EDMs), and up
to eight voice/FAX (VFAX) modules. Brief descriptions of the AD-10
modules follow.
q
q
q
q
q
The core module provides the basic functionality of the AD-10
including control processing and TDM multiplexing. The core module
also provides interfaces for the telephone company (telco) ports, network
port (RS-422, V.35, or V.11), and supervisory channel.
The Hybrid Data Module (HDM) provides four data port interfaces
with three ports operating as RS-232 interfaces and one port
configurable to RS-232, RS-422, or V.35 operation. All four ports are
configurable to either TDM mode or packet mode.
The Expansion Data Module (EDM) provides four data port interfaces
with three ports operating as RS-232 interfaces and one port
configurable to RS-232, RS-422, or V.35 operation. All four ports
support packet mode such that each port is configurable to process
either Bisync, HDLC/SDLC, or an asynchronous protocol. The EDM
does not support TDM mode.
The Voice/FAX (VFAX) module supports compressed voice, fax
modem, and data modem signals. Versions include US VFAX, BABT
VFAX, Austel VFAX, and VDE/TUV VFAX.
The ringer module generates #48 VDC, ringer waveform, and other
voltages required by the VFAX module.
Figure 31 shows the open-ended architecture of the AD-10 and how
easy it is to add new modules.
84
Product Overview
CORE
MODULE
VOICE/FAX
MODULE
C
TR
32
RS2
M
AR
85
AL
4
T
RS4
IN
OU
RT
RINGER
MODULE
LE
PO
NSO
CO
3
RT
RK
PO
WO
NET
2
4
1
3
2
1
DATA
MODULES
Figure 31. AD-10 (inside)
ST Interface
The AD-10 communicates with the ST node using a proprietary
subrate TDM format that carries AD-10 supervisory band, subrate
TDM data, and the AD-10 packet band.
The AD-10 aggregate can enter the ST node as either a 64-kbps
channel on a T1 or E1 interface or at speeds of 19.2, 56, or 64 kbps
through a Synchronous Data Module (SDM) interface. The aggregate
dynamically mixes subrate data and voice channels to create a single
19.2-kbps, 56-kbps, or 64-kbps aggregate data stream. Figure 32
illustrates the two ways an AD-10 aggregate can enter the ST node.
85
Product Overview
VOICE
VOICE
TDM
TDM
TDM
PACKET
1 2 3 4 5 6
AD-10
VOICE AND DATA
CHANNELS
A
1
2
7
8
ONE 64-KBPS
BUNDLE
T
1
M
PUBLIC
TELEPHONE
NETWORK
B
A
AD-10
AD-10 AGGREGATE
DATA STREAM
3
4
5
9
S
D
M
F
S
M
VOICE
TDM
PACKET BAND
19.2/64-KBPS
OR
56/64-KBPS
SERIAL
CONNECTION
TDM (HDLC)
PACKET BAND
B
S
G
M
E 64-KBPS
1 CHANNEL
M
OTHER
BUNDLES
24/31
CHANNELS
7 VOICE
8 VOICE
9 TDM
10 TDM (HDLC)
11 PACKET
12 PACKET
13 PACKET
14 PACKET
64-KBPS
CHANNEL
INL
6
11
12
13
14
PACKET
10
TDM (HDLC)
VOICE
VOICE
TDM
PACKET BAND
A AD-10/ST INTERFACE VIA T1M/E1M
1 - 6 SAMPLE DATA STREAMS
B AD-10/ST INTERFACE VIA SDM
7 -14 SAMPLE DATA STREAMS
Figure 32. AD-10 Logical Interface with ST Node
As indicated in Figure 32, the network node communicating with the
AD-10 must be equipped with one of the I/O modules for physical
interface as previously mentioned and with a Subrate Grooming
Module (SGM) to terminate the AD-10 aggregate. The SGM
demultiplexes the AD-10 proprietary subrate format. It also generates
and terminates the AD-10 supervisory band. When packet channels are
included in the AD-10 aggregate, an FSM is required for switching the
packet channels.
86
Product Overview
Traffic from up to 16 data ports is multiplexed into a 19.2-kbps, 56kbps, or 64-kbps aggregate. Data streams are programmable at rates of
1.2 kbps to 56 kbps, depending on network configuration.
Port Capabilities
Table 5 describes AD-10 user port capabilities in detail.
Table 5. AD-10 User Ports
Port Format
Description
•
•
•
•
•
•
Voice
TDM
•
•
Packet
•
•
Up to eight telephone voice channels
Full V.29 9.6-kbps Group III fax rate
Compression rates from 5.3 to 32 kbps
Up to four TDM mode data ports
Three standard RS-232 channels
One high-speed channel selectable between
V.24/RS-232, RS-422, and V.35
Baud rates to 56 kbps synchronous
Statistical multiplexing functionality to handle
packet mode data (HDLC, bisynchronous,
asynchronous)
Up to 16 standard V.24/RS-232 channels
One high-speed channel selectable between
V.24/RS-232, RS-422, and V.35
TDM Support
An AD-10 aggregate is typically composed of voice channels, subrate
channels from TDM-mode data ports, and a packet band carrying data
from packet-mode data ports.
AD-10 TDM channels can be destined for local or remote synchronous
data or server ports. The unit supports synchronous speeds from
1.2 kbps to 56 kbps as listed in Table 6.
Table 6. AD-10 TDM Port Speeds
Format
Synchronous
Supported Speeds
1.2, 2.4, 4.8, 7.2, 8, 9.6, 14.4, 19.2, 32, 38.4, 48, 56 kbps
87
Product Overview
Voice Support
The AD-10 delivers very high-quality voice at compressed rates as
low as 5.33 kbps. This not only reduces cost for voice-intensive
applications, but also satisfies users by providing reliable call
connections and extremely clear reception.
AD-10 features include the following:
q
q
q
q
q
Compression choices that offer increased flexibility and maximum
efficiency in voice processing:
•
Use of the Code Excited Linear Prediction (CELP) algorithm, an
advanced analog-to-digital voice coding scheme with compression
rates of 5.33, 8, and 9.6 kbps
•
Use of the Adaptive Transform Coding (ATC) algorithm with
compression rates of 7.47 kbps to 32 kbps in 533-bps increments
Echo cancellation that meets or exceeds ITU-T G.165 for near-end
echoes delayed by 0 to 32 milliseconds and supports an Echo Return
Loss (ERL) of 6 dB or higher
Transmit and receive levels within the range of #25.4 dB to +25.4 dB in
0.2-dB increments
Full V.29, 9.6-kbps Group III fax rate
Connections for up to eight 2-wire FXS/FXO or 2- and 4-wire E&M
voice channels (types I, II, III, IV, or V)
Compressed voice channels are carried as TDM channels. AD-10
voice compression is compatible with ASM voice compression.
The AD-10 aggregate, which is the total bandwidth carrying the
multiplexed data stream, uses a demand bandwidth assignment
method. This method permits low bit-rate voice channels to
dynamically contend for the available bandwidth.
Packet Support
Using frame relay techniques, the AD-10 statistically multiplexes the
data from the packet data ports into a "packet band" stream for
transport to the backbone network. The statistical multiplexer allows
the configured packet bandwidth to be shared among the packet mode
88
Product Overview
ports by building variable-length frames. The TDM multiplexer,
which processes information through a fixed bandwidth, treats the
packet band as a single TDM channel when forming the AD-10
aggregate.
After demultiplexing the AD aggregate, ST presents the packet band
to a Frame Server Module (FSM) port. The FSM demultiplexes the
data link connection identifiers (DLCIs) and routes the packet
channels appropriately. These packet channels terminate on a local or
remote data port.
Also, if an external device such as a router presents the AD-10 with
concentrated LAN traffic (data that is already statistically
multiplexed), the AD-10 can carry the traffic on a TDM channel to the
FSM in the node.
Table 7 lists AD-10 packet port speeds.
Table 7. AD-10 Packet Port Speeds
Format
Supported Speeds
HDLC/
Bisynchronous
1.2, 2.4, 4.8, 7.2, 8, 9.6, 14.4, 19.2, 32, 38.4, 48, 56, and
64 kbps
Asynchronous
0.15, 0.3, 1.2, 2.4, 4.8, 9.6, 19.2, and 38.4 kbps
Physical Description
As shown in Figure 33, the front panel of the AD-10 contains
indicators that monitor the device's operating state:
q
q
q
The green Sync indicator lights when the unit is in normal operation and
has acquired synchronization on its network port.
The red Alarm indicator lights when a system alarm is detected. The
indicator remains lit as long as the alarm condition persists.
The amber Test indicator lights when the unit enters a self-test mode, an
internal reset mode, or a user-initiated diagnostic procedure.
89
Product Overview
Figure 33. AD-10 Front Panel
As shown in Figure 34, the rear panel contains all connectors and port
interfaces. Available connections vary and are determined by the unit's
configuration and the subscriber device interface requirements. Since
the design is modular, it is easy to reconfigure the AD-10. Interfaces
include:
q
q
q
Two telephone company (telco) ports that can support up to eight voice
channels
Data ports that can support one Hybrid Data Module and up to three
Expansion Data Modules
A supervisory port interface for local management and configuration
OPTIONAL PORTS
TELCO PORTS
NETWORK
PORT
BABT TELCO
RS-485/
RETURN
RS-232
CONNECTOR
IN SWITCH
POWER
(TRC)
BABT
ALARM
SWITCH
PROTECTED
EARTH (PE)
CONSOLE OUT
PORT ALARM
Figure 34. AD-10 Rear Panel
90
Product Overview
AD-7
The AD-7 is a six-port TDM multiplexer that provides a cost-effective
channel extension of the ST network. The AD-7 is designed to take
advantage of existing wiring plant to extend digital data service and is
perfect for small branch sites and large "campus-like" environments.
Figure 35 shows the front panel view of the AD-7.
The AD-7 is powered from local AC mains through an AC adapter.
In order for an ST node to communicate with an AD-7, the node must
be equipped with the I/O interface called the Remote Termination
Module (RTM). The RTM carries the AD-7 port data, supervisory
data, and overhead.
ST Interface
The physical interface between the AD-7 and the RTM in the node is a
standard two-wire U-interface conforming to ANSI T1.601-1992
specifications. This interface can drive connections for up to 5.5
kilometers (3.5 miles or 18,000 feet) over 19-gauge twisted-pair cable.
One ST-1000 node can support up to 60 RTMs. Each RTM can
connect up to 12 AD-7 units; therefore, each ST-1000 node can
connect up to 720 ADs.
In addition to needing an RTM for the physical interface, the AD-7
requires a Subrate Grooming Module (SGM) if the RTM sends subrate
data out of the node. The RTM demultiplexes the AD-7 network
aggregate and also generates and terminates the AD-7 supervisory
channel.
91
Product Overview
ST routes the AD-7 subrate channels through the ST subrate
subnetwork. The AD-7 channel is treated as any other ST-originated
channel. AD-7 channels of bit-stuffed 56 kbps, 64 kbps, and 128 kbps
are routed as N x 64 kbps channels.
Supervisory Band
The AD-7 supervisory band provides AD-7 status and statistical
information to the ST node and enables the node to:
q
Configure AD-7 ports
q
Soft-download AD-7 operating software
q
Perform diagnostics and report on results
Ports
As shown in Figure 36, the AD-7 has six input ports that can be
configured as either synchronous or asynchronous. The unit supports
synchronous speeds from 1.2 kbps to 128 kbps and asynchronous
speeds from 150 bps to 38.4 kbps as listed in Table 8.
Table 8. AD-7 Port Speeds
Format
Supported Speeds
Synchronous
1.2, 2.4, 4.8, 7.2, 8, 9.6, 14.4, 19.2, 32, 38.4, 48, 56, 64, and
128 kbps
Asynchronous
0.15, 0.3, 1.2, 2.4, 4.8, 9.6, 19.2, and 38.4 kbps
If two port interfaces are available but one channel is operating at
128 kbps, then the other channel cannot be used. Rates less than
56 kbps are treated as subrates and can be groomed with other subrate
data before being transported through the system.
PORT 4
PORT 5
PORT 6
CRAFT
PORT 1
PORT 2
LINE
POWER
ADAPTER
PORT 3
92
Product Overview
Two-wire timing is provided by the ST analog loop from the RTM.
The AD-7 derives its clock from the ST to provide timing to all AD-7
synchronous I/O ports. The I/O ports can be individually configured
with the following optional interfaces:
q
q
q
X.21
V.24
V.35
The V.24 interface supports only up to 38.4 kbps in the synchronous
mode. An AD-7 supports a maximum of two V.35 interfaces.
The AD-7, using the 2-wire interface, can drive up to 18,000 feet
without repeaters. The AD-7 can be remote from the backbone node
and use private lines to access the private network. To serve a growing
campus or metropolitan network, the AD-7 uses existing copper
wiring.
AD-3
The AD-3 is a two-port TDM multiplexer that, like the AD-7,
provides a cost-effective channel extension of the ST network. The
AD-3 can accommodate smaller branch locations and other sites with
a modest amount of traffic. As a stand-alone multiplexer the AD-3
provides TDM synchronous and asynchronous data input to an ST
network. The AD-3 input aggregate can contain asynchronous subrate
data, synchronous subrate data or a 64-kbps data stream, supervisory
data, or a single channel operating at 128 kbps.
Amazingly compact, the AD-3 is about the size of a small clock radio
and fits conveniently on a desk. Figure 37 shows the AD-3 front panel
and Figure 38 shows the rear panel.
93
Product Overview
Although the AD-7 and the AD-3 differ in size and number of ports,
their technical specifications are identical. For example, both the AD-7
and AD-3 interface with the ST network through the RTM. Both
devices communicate with ST via the supervisory band and support
the same formats and port speeds. For details, see the discussion on
"AD-7" earlier in this section.
D25
D25
RJ11
RJ48
POWER
ADAPTER
Synchrony AR
The AR systems are frame relay access devices (FRADs) designed for
remote office internetworking. The ARs provide standards-based,
multiprotocol routing and Media Access Control (MAC) layer
bridging supporting Ethernet, Token Ring, and a variety of wide area
network interface types including X.25, Frame Relay, Switched
Multimegabit Data Service (SMDS), point-to-point protocol (PPP),
and link access procedure balanced (LAPB) at speeds up to 2.048
Mbps. Express Switching architecture provides the appropriate
qualities of service for LAN or legacy, SMDS, ISDN, downloadable
software support, and LAN Network Manager support.
Three models are available: AR-350, AR, and AR-150. The AR-350,
which is the highest capacity model in the AR group, is a
desktop/rack-mountable four-slot modular unit capable of mixing and
matching WAN interfaces. The AR-350 can support up to twelve LAN
ports, twelve WAN ports, and ninety-six 10BASE-T ports. Similar to
the AR-350, the AR is a desktop/rack-mountable two-slot modular
unit capable of mixing and matching WAN interfaces. The AR can
support up to two LAN ports, three WAN ports, and twelve 10BASET ports. The AR-150 is a desktop unit that supports fixed
configurations for small branch locations. The AR-150 can support up
to two LAN ports and three WAN ports.
94
Product Overview
Synchrony BNP
The BNP systems are modular X.25 legacy switches and frame relay
FRADs that support X.25, bisynchronous, Burroughs Poll,
asynchronous, synchronous data link control (SDLC), and high-level
data link control (HDLC) protocols. The BNPs offer data
compression, encryption, and remote downloading as well as extensive
IBM support including multidrop, QLLC, and SDLC spoofing (an
efficient and proprietary method of relaying the control protocol
without the need to transmit the protocol across the network). The
BNPs support a wide range of interfaces including ISDN Basic Rate
Interface (BRI) and support speeds up to 2 Mbps.
The BNPs are available in two models: BNP-350 and BNP. The BNP350 supports up to 18 ports and has a data throughput of 500 pps. The
BNP supports up to 10 ports and has a data throughput of 500 pps.
Synchrony IAN
The IAN systems are modular branch devices that integrate LAN and
legacy traffic over a single wide area network and provide frame relay
and X.25 switching. The IANs support bisynchronous, Burroughs
Poll, asynchronous, and SDLC/HDLC protocols. Additionally, the
IANs offer extensive IBM support including multidrop, QLLC, SDLC
spoofing, SDLC to LLC2 conversion, and downloadable software
support. The IANs also support Switched Multimegabit Data Service
(SMDS), ISDN, and Express Switching architecture.
The IANs are available in two models: IAN and IAN-150. The IAN
supports a maximum of 13 ports (9 WAN ports and 4 LAN ports). The
IAN-150 supports a maximum of 7 ports (5 WAN ports and 2 LAN
ports).
95
Product Overview
Synchrony Specifications
The following tables provide specifications of the ST-1000 and ST-20
nodes, and of the AD-10, AD-7, and AD-3 access devices.
Table 9. ST-1000 Node Specifications
Specification
Description
Network management
SNMP-based, HP OpenView platform
(SNMS and/or EMS 200)
Module slots
One control shelf:
17 slots (2 reserved for ST common equipment,
1 reserved for IRP with bus arbitration
daughterboard, if required)
Up to three expansion shelves:
(2 slots reserved for ST common equipment)
Configuration
Rack or cabinet mount
Shelf size
Height: 25.6 in. (650 mm) single AC;
32.1 in. (813 mm) dual AC
Width: 17.7 in. (450 mm)
Depth: 19.7 in. (500 mm); 23.6 in. (600 mm)
with front cover and rear cable bracket
Approximate weight
Control shelf (without modules):
35 lb (15.9 kg) single AC;
50 lb (22.7 kg) dual AC
Average module: 1.75 lb (.79 kg)
Power supply: 8 lb (3.63 kg)
Fan assembly: 6.5 lb (3 kg)
Power requirements for AC
applications
100-120 VAC, 16-amp maximum, 50-60 Hz,
40-amp peak inrush current
Power requirements for
-48 VDC applications*
-40 to -60 VDC, 40-amp maximum, 40-amp
peak inrush current
Operating temperature
10° to 45° C
Operating humidity
10% to 90% relative humidity, noncondensing
Operating altitude
Up to 10,000 ft (3050 m)
Heat dissipation
1100 W, 3224 BTUs per hour maximum per
shelf
* Two independent 50-amp DC input power lines are provided. An ST-1000 node can
operate with a single line in a customer premise equipment (CPE) environment or with
dual lines in an A and B carrier environment.
96
Product Overview
Table 10. ST-20 Node Specifications
Specification
Description
Network management
SNMP-based, HP OpenView platform
Configuration
One stand-alone control shelf:
12 slots (1 reserved for common equipment)
Shelf size
Height: 19.7 in. (500 mm)
Width: 17.7 in. (450 mm)
Depth: 19.7 in. (500 mm); 23.6 in. (600 mm)
with front cover and rear cable bracket
Approximate weight
Control shelf (without modules): 32 lb (14.6 kg)
Average module: 1.75 lb (.79 kg)
Power supply: 5 lb (2.27 kg)
Fan assembly: 4.5 lb (2.08 kg)
Power requirements for AC
applications
Power requirements for
-48 VDC applications*
-40 to -60 VDC, 20-amp maximum, 150-amp
peak inrush current
0° to 45° C
Operating humidity
Operating altitude
Up to 13,000 ft (4000 m)
Heat dissipation
775 W, 2272 BTUs per hour maximum per
shelf
* Two independent 50-amp DC input power lines are provided. An ST-20 node can
operate with a single line in a customer premise equipment (CPE) environment or with
dual lines in an A and B carrier environment.
Table 11. AD-10 Specifications
Specification
Configuration
Size
Approximate weight
Power requirements
Storage temperature
Operating humidity
Operating altitude
Heat dissipation
Description
Compatible with fixed shelf and rack-mounting
kit
Height: 5.25 in. (133 mm)
Width: 17.75 in. (450 mm)
Depth: 17.75 in. (450 mm)
25.5 lb (11.5 kg)
110 or 230 VAC, 200 W maximum, 50-60 Hz
-20° to 80° C
0° to 45° C
0 to 95% relative humidity, noncondensing
Up to 13,000 ft (4000 m)
700 BTUs per hour maximum
97
Product Overview
Specifications
Configuration
Size
Approximate weight
Power requirements*
Operating humidity
Operating altitude
Heat dissipation
Description
Table-top
Height: 2 in. (51 mm)
Width: 11.75 in. (298 mm)
Depth: 7.6 in. (193 mm)
2.5 lb (1.1 kg)
110 or 230 VAC, 15 W maximum,
50-60 Hz
0° to 50° C
Up to 13,000 ft (4000 m)
* Device is powered from local AC mains. An external adapter is required.
Specification
Configuration
Size
Approximate weight
Power requirements*
Operating humidity
Operating altitude
Heat dissipation
Description
Table-top
Height: 1.75 in. (44.5 mm)
Width: 9.25 in. (235 mm)
Depth: 8.5 in. (216 mm)
1.75 lb (.79 kg)
110 or 230 VAC, 8 W maximum, 50-60 Hz
0° to 50° C
Up to 13,000 ft (4000 m)
* Device is powered from local AC mains. An external adapter is required.
98
Modular Node Design
Modules fall into one of four categories:
common equipment, I/O, server, or
internetworking.
S
ynchrony ST provides a modular networking systemone
that can easily be scaled to meet dynamic application and
capacity requirements to keep pace with your business.
Modules fall into one of four categories: common equipment, I/O,
server, or internetworking. Great flexibility exists as to the types of
modules and how many of each can be used by the nodes on your
network. In addition, all control, I/O, and server modules are
interchangeable between the ST-1000 and the ST-20.
The modular architecture functionally separates I/O and traffic
transmission from switching services. As a result, nodes can costeffectively channel processed traffic from one or more servers to one
or more interface ports.
ST supports a mix of various types of switching and services ranging
from traditional time division multiplexing (TDM) transport to highcapacity frame switching. Because demand for these switching
technologies varies depending on the applications supported and the
carrier services available, appropriate technology can be easily
integratedquickly and affordablywhen necessary.
99
Modular Node Design
ST also provides flexible and cost-efficient local area network (LAN)
internetworking. The internetworking solutions of Ascom Timeplex
emphasize features and functions that efficiently utilize wide area
resources and provide industry-standard interoperability.
1
2
3
N
C
P-1
C
IL
ALM
IL
IL
FA
BY
STL
N
O
B
STL
N
O
ALM
1
N
LA
B
STL
N
O
2
4
2
LO
1
3
1
3
2
4
LO
IL
2
IL
3
EM
R
C
FA
BY
STL
N
O
1
-8
M 4
SD V.2
IL
-1
XM
IL
4
4
2
P1-
P1-
FA
2
1
KT
C 1
KT
C
4
4
P1-
P1-
IL
FA
Y
B
STL
N
O
R
4
L
P1-
IL
FA
Y
M
4
1
LK
C
P1-
ST
B
STL
N
O
-8
M 4
SD V.2
4
4
LK
C
P1-
L
H
P1-
ST
S
O
M
O
FA
BY
STL
N
O
T
4
P1-
H
AC
IL
S
O
FA
BY
STL
N
O
-8
M 4
SD V.2
17
EM
R
C
O
4
LO
4
P1-
T
AC
-8
M 4
SD V.2
16
EM
D
O
LO
4
M
3
6
-1
M
FS
2
EM
R
C
FA
BY
STL
N
O
1
15
EM
D
O
LO
4
M
3
6
-1
M
2
IL
1
14
EM
R
C
LO
4
FA
BY
STL
N
O
FS
13
3
EM
R
C
IL
-4
M L
E1 BA
12
FA
BY
STL
N
O
1
3
EM
R
C
IL
2
4
LO
T
AF
R
FA
BY
STL
N
O
-4
M L
E1 BA
11
C
EM
R
C
IL
2
4
LO
T
AF
R
FA
BY
STL
N
O
-4
M L
E1 BA
10
C
EM
R
C
IL
-4
M L
E1 BA
9
FA
BY
STL
N
O
3
1
N
LA
-1
-4
M SX
T1 D
8
-4 -1
IL
M SX
FA
T1 D
Y
7
-4 -1
IL
M SX
FA
T1 D
Y
6
FA
BY
STL
N
O
P-1
FA
BY
STL
N
O
-4 -1
M SX
T1 D
5
N
LB
A
4
P1-
4
S
M
AR
AL
P1-
S
M
AR
AL
2
8
P5-
8
P5-
8
P5-
8
P5-
B
D
R
SD
1
D
R
2
SD
3
1
5
D
R
2
SD
4
3
1
6
5
D
R
7
2
SD
4
3
8
1
6
4
2
7
5
3
8
6
4
7
5
6
V
+5
8
7
8
2V 2V V ND
–1 +2 G
+1
100
4
Figure 39. ST-1000 Control Shelf with Modules
Common Equipment Modules
Common equipment modules are necessary to control the node and to
extend or terminate the bus. Table 14 summarizes the common
equipment modules.
Modular Node Design
Table 14. Common Equipment Modules
Module
Description
NCP-3
NCP-2
Nodal Control Processors: control and perform clocking for ST-1000
and ST-20 nodes; terminate ST-20 bus. NCP-3 provides more
memory capacity than NCP-2.
RXM-1
Right Expansion Module: expands or terminates bus on right end of an
ST-1000 shelf (not applicable to ST-20)
LXM-1
Left Expansion Module: expands bus on left end of an ST-1000
expansion shelf (not applicable to ST-20)
NC
P-
3
IL
FA
BY
ST L
ON
AL
M
V
+5
2V 12V ND
G
+1
When set up to perform bandwidth manager functions, the control
shelf of the ST-1000 always contains a Nodal Control Processor and a
Right Expansion Module, while additional ST-1000 shelves
(maximum of three) must be equipped with both a Left Expansion
Module and a Right Expansion Module. The ST-20 is a single-shelf
unit that does not use expansion modules.
LA
N
Nodal Control Processor
The Nodal Control Processor (NCP) provides nodal intelligence,
controls the backplane, and performs clocking for an ST node. The
NCP is available in two models: NCP-3 and NCP-2. Figure 40
illustrates the front panel of the NCP-3 module.
CR
AF
T
MO
DE
M
NCP modules are based on a 32-bit Motorola 68EC030 processor and
hold the configuration for all soft-loadable modules. They have an
internal clock with Stratum 3 accuracy, and also manage external
station clock inputs.
ST
CL
K
1
Both the NCP-3 and NCP-2 perform the following functions:
q
q
q
q
q
2
Control the transfer of TDM and packet data between modules across
the backplane bus
AL
AR
MS
Communicate status and control among the modules
Communicate supervisory information to other ST nodes
Control clocking for the node, including either internally generated or
externally supplied clocks. Clock sources can be internal clocks, T1 or
E1 digital facilities, I/O synchronous channels, and station clocks.
Supply an interface to the Synchrony Network Management System and
a Craft Person Station (CPS)
Figure 40.
101
Modular Node Design
q
q
q
LX
RX
M-
M-
1
1
CK CK F
T T AI
1 2 L
CK CK F
T T AI
1 2 L
LB
A
LB
A
Store execution code for all circuit modules
Configure the node
Incorporate the functionality of the Right Expansion Module
Although the NCP modules are similar, the NCP-3 provides more
memory capacity than the NCP-2. The NCP-3 provides additional
FLASH memory for nonvolatile program storage, additional batterybacked RAM (BBRAM) for nonvolatile database storage, and
additional dynamic RAM (DRAM) for program operation. The
NCP-3 is required in a node that is equipped with a LINK/+ Gateway
Module (LGM) or a D-Channel Server Module (DSM).
An NCP module always resides in the first slot of a node. In a
redundant configuration, the standby NCP resides in the second slot
and provides 1:1 redundancy.
Right Expansion Module
B
B
The Right Expansion Module (RXM) is a common equipment module
used in an ST-1000 node to expand the backplane add bus from one
shelf to the next or to loop data from the add bus flowing toward it to
the drop bus flowing away from it. The RXM is illustrated in
Figure 41.
The RXM operates in expansion mode when it is used to interface to
another shelf. In this mode the RXM receives information from the
add bus and carries this data over the intershelf cable to the
downstream shelf of the node. Concurrently, the RXM receives
information from the downstream shelf over the intershelf cable and
carries this information onto the drop bus on the backplane. In a
multishelf configuration you can also establish a loop in an RXM for
diagnostic purposes.
+5
V
+1
2V
–1
2V
+2
V
GN
D
Figure 41. Right and Left
Expansion Modules
102
The RXM always operates in termination mode when it is in the last
(or only) shelf of a node. Here, the RXM provides a connection
between the add bus flowing toward it and the drop bus flowing away
from it.
When operating in either expansion or termination mode, the RXM
also contains dual circuits for full 1:1 redundancy and switchover in
case of failure or for testing. The RXM is always installed in the last
slot (17) of a control or expansion shelf.
Modular Node Design
Left Expansion Module
The Left Expansion Module (LXM) is a common equipment module
used in an ST-1000 expansion shelf to connect the intershelf cable
from the upstream shelf and the backplane bus of the expansion shelf
on which it resides. The LXM is illustrated in Figure 41.
Diagnostically, you can also use the LXM to loop the add and drop
buses back to the previous RXM. This is especially useful to pinpoint
defective intershelf connections.
Like the RXM, the LXM contains dual circuits for full 1:1 redundancy
and switchover in case of failure. The LXM is always installed in the
first slot of an expansion shelf. Figure 29, in the previous section,
illustrates the use of the RXM and the LXM in an ST-1000 multi-shelf
configuration.
I/O Modules
The input/output (I/O) modules provide the interfaces between the ST
network and its users. The modules can connect networking devices,
internodal links (INLs), and public network access facilities.
The physical and electrical interfaces of these modules are protocol
independent. This versatility allows connection to a variety of
networks. For example, different ports on the same I/O module or
even different bundles on the same T1/E1 can be used as a frame relay
interface to a router, as a connection to a digital PBX, and as an
internodal link between ST switching nodes and AD systems.
The user shelf slots in the ST switching nodes are universal and can
accommodate any I/O or server module. The number of I/O modules
that you can install in a node is limited only by the number of
available slots.
I/O modules function independently from servers and therefore are not
restricted to supporting a specific server function. Consequently the
ST node is able to channel processed traffic from one or more servers
to one or more interface ports. As a result, ST provides maximum
service flexibility with minimal changes in hardware.
Any type of traffic can be sent over I/O modules in a variety of
formats. All I/O modules present data to the bus in an N x 64 kbps
format. Table 15 describes the four I/O modules currently available.
103
Modular Node Design
Table 15. I/O Modules
Module
T1
M
DS -4
X1
ON STB FA
L Y IL
Description
T1M
Provides an interface for channelized synchronous data from
internodal links or user I/O devices at T1 (1.544 Mbps) or fractional
T1 speeds
E1M
Provides an interface for channelized synchronous data from
internodal links or user I/O devices at E1 (2.048 Mbps) or fractional
E1 speeds
SDM
Provides an interface for synchronous user data at subrate speeds
(less than 56 kbps) or superrate speeds (N x 56 kbps and/or N x 64
kbps up to 2.048 Mbps)
RTM
Provides a network access point for remote termination of an AD-7
or AD-3
1
2
3
T1 Module
4
LO RE
C M
The T1 Module (T1M) provides a standard T1 interface between
backbone nodes (generally carrier-owned facilities), between
collocated nodes (generally premise-based wiring and cabling), or
between a node and a user I/O device. The T1 standard is supported by
North American and Japanese facilities. Figure 42 illustrates the front
panel of a T1M.
P1
-4
A T1M has four physical T1 portseach operating at a port data rate
of 1.544 Mbps and capable of supporting up to 24 channels of 64
kbps. Channels can be logically bundled together in multiples of 64
kbps. There is no restriction on how to bundle the bandwidth. Possible
assignment methods include alternate, contiguous, or arbitrary time
slots.
You can configure an N x 64 kbps bundle to carry any of the
following data types:
q
Figure 42.
T1 Module
104
q
q
q
q
q
Pulse code modulated (PCM) (restricted to one 64-kbps channel per
bundle)
Time division multiplexed
Frame relay
High-level data link control (HDLC)
AD-10 aggregate (restricted to one 64-kbps channel per bundle)
Internodal link (INL)
Modular Node Design
The T1M provides appropriate T1 digital signaling and framing.
Trunk conditioning is automatically performed by the module.
The T1M also supports line encoding schemes of either binary 8-zero
substitution (B8ZS) or alternate mark inversion (AMI).
You can choose from user-configurable framing formats that are
compliant with Super Frame (SF), ANSI Extended Super Frame
(ESF), or AT&T ESF. Since compliance extends to ESF, the T1M
provides frame synchronization, cyclic redundancy checking, and data
link bits. And all ESF statistics are available to the network
management system and to the carrier.
The T1M is 1:1 redundant. To provide redundancy, two T1Ms must be
inserted in consecutive slots, starting with an odd-numbered slot.
When module hardware faults are detected, redundancy switchover
occurs without disconnecting the channels. Data link facility
redundancy is managed through the use of a Y-cable and the T1M.
Table 16 summarizes T1M specifications.
Table 16. T1 Module Specifications
Type
T1M-4/DS-1
T1M-4/DSX-1
Ports
4
Support
• Up to 24
•
channels of
64 kbps per
port
AMI and
B8ZS line
encoding
Channel Data Rates
Compliance
N x 64 kbps, where
N = 1 to 24 inclusive
SF, ANSI
ESF, AT&T
ESF
T1M-4/DS-1
The T1M-4/DS-1 electrical interface offers Digital Service Level 1
(DS1). In North America, DS1 is 1.544 Mbps. DS1 accommodates up
to 24 voice conversations, each encoded at 64 kbps. T1M-4/DS-1
complies with DS1 electrical interfaces to central offices and does not
require a repeater for distances up to 6,000 feet. The module includes
an integral Channel Service Unit (CSU) for terminating the digital
channels.
105
Modular Node Design
T1M-4/DSX-1
The T1M-4/DSX-1 electrical interface provides DSX-1 interfaces
conforming to AT&T CB119 and Canadian CS-03. T1M-4/DSX-1
offers the set of parameters necessary for connecting equipment at
distances up to 655 feet. The module can also attach to an external
CSU.
E1
M
BA -4
L
E1 Module
The E1 Module (E1M) provides a standard E1 interface between
backbone nodes (generally carrier-owned facilities), between
collocated nodes (generally premise-based wiring and cabling), or
between a node and a user I/O device. The E1 standard is supported by
European facilities. Figure 43 illustrates the front panel of the E1M-4.
ON STB FA
L Y IL
1
2
3
4
LO RE
C M
The E1M-4 has four physical E1 portseach operating with or
without channel-associated signaling at a port data rate of 2.048 Mbps
and capable of supporting up to 31 channels of 64 kbps. Channels can
be logically bundled together in multiples of 64 kbps. There is no
restriction on how to bundle the bandwidth. Possible assignment
methods include alternate, contiguous, or arbitrary 64 kbps.
P1
-4
You can configure an N x 64 kbps bundle to carry any of the
following data types:
q
q
q
q
q
q
Pulse code modulated (PCM) (restricted to one 64-kbps channel)
Frame relay
AD-10 aggregate (restricted to one 64-kbps channel)
Framing formats for the E1M are compliant with ITU-T G.703,
G.704, and G.732. The module also supports HDB3 line encoding. It
performs A-law to µ-law conversion on a 64-kbps basis.
Figure 43.
E1 Module
106
The E1M is 1:1 redundant. To provide redundancy, two E1Ms must be
inserted in consecutive slots, starting with an odd-numbered slot.
Modular Node Design
When faults are detected, redundancy switchover occurs without
disconnecting the channels.
Table 17 summarizes E1M specifications.
Table 17. E1 Module Specifications
Type
E1M-4/Bal
E1M-4/Ubal
Ports
4
Support
•
•
E1M-2/Bal
E1M-2/Ubal
Up to 31
channels of 64
kbps per port
HDB3 line
encoding
Channel Data
Rates
N x 64 kbps,
where N = 1 to 31
inclusive
Compliance
ITU-T
G.703,
G.704,
G.732
2
E1M-4/Bal
The E1M-4/Bal I/O module is balanced at 120 ohm and complies with
G.703, G.704, and G.732, the ITU-T standards covering transmission
facilities. In a balanced electrical interface, each circuit consists of a
separate pair of wires, which generally allows data to be transmitted
over longer distances than an unbalanced electrical interface.
E1M-4/Ubal
The E1M-4/Ubal I/O module is unbalanced at 75 ohm and complies
with ITU-T G.703, G.704, and G.732.
E1M-2/Bal
The E1M-2/Bal I/O module is balanced at 120 ohm and complies with
ITU-T G.703, G.704, and G.732.
E1M-2/Ubal
The E1M-2/Ubal I/O module is unbalanced at 75 ohm and complies
with ITU-T G.703, G.704, and G.732.
107
Modular Node Design
Synchronous Data Module
SD
M
V. -8
24
The Synchronous Data Module (SDM) provides an interface for
synchronous user data operating at subrate speeds (less than 56 kbps)
and superrates (up to 2.048 Mbps in multiples of 56 or 64 kbps).
Figure 44 illustrates the front panel of an SDM.
ON STB FA
L Y IL
P1
-4
P5
-8
An SDM can support local user I/O devices and/or internodal links
(INLs). A port can be configured as either a DCE or DTE interface,
whichever complements the device connected to it. An SDM port can
carry any of the following data types:
q
q
q
q
q
Frame relay
AD-10 aggregate (restricted to one 64-kbps channel)
The SDM also transfers function leads between I/O devices and the ST
bus. When required, the SDM provides a clock source to the node.
SDM support of N x 64 kbps clocking generates N x 56/64 kbps,
where N equals 1 to 31. Support of satellite buffering provides
1 millisecond of buffering regardless of data rate.
SD
RD
1
2
3
4
5
The SDM-4R is 1:1 redundant. To provide redundancy, two SDM-4Rs
must be inserted in consecutive slots, starting with an odd-numbered
slot. When faults are detected, redundancy switchover occurs without
disconnecting the channels.
6
7
8
Figure 44.
Synchronous Data Module
108
The key generator (KG) resynchronization feature allows an ST node
to indicate to an external encryption device that an SDM INL is out of
sync. The device can then go into resynchronization mode and return
the INL to an in-sync condition.
Table 18 summarizes SDM specifications.
Modular Node Design
Table 18. Synchronous Data Module Specifications
Type
Ports
Support
Channel Data
Rates
Compliance
SDM-8/
V.11
8
User I/O only
From 1.2 kbps
to 2.048 Mbps
per port
ITU-T X.21, V.36,
and EIA RS-422,
RS-449, RS-530
interfaces
SDM-8E/
V.11
8
User I/O and/or INL
Satellite buffering
N x 64 kbps clocking
KG resynchronization
From 1.2 kbps
to 2.048 Mbps
per port
ITU-T X.21, V.36,
and EIA RS-422,
RS-449, RS-530
interfaces
SDM-8/
V.35
8
User I/O only
From 1.2 kbps
to 2.048 Mbps
per port
ITU-T V.35
interface
SDM-8E/
V.35
8
User I/O and/or INL
Satellite buffering
From 1.2 kbps
to 2.048 Mbps
per port
ITU-T V.35
interface
SDM-8/
V.24
8
User I/O only
From 300 bps
to 38.4 kbps
per port
ITU-T V.24, EIA
RS-232 interfaces
SDM-4R/
V.11
4
User I/O and/or INL
Redundancy
Satellite buffering
From 1.2 kbps
to 2.048 Mbps
per port
ITU-T V.11
interface
SDM-4R/
V.35
4
User I/O and/or INL
Redundancy
Satellite buffering
From 1.2 kbps
to 2.048 Mbps
per port
ITU-T V.35
interface
SDM-4R/
E1-Bal
4
User I/O and/or INL
Redundancy
Satellite buffering
2.048 Mbps
per port
ITU-T G.703
balanced interface
SDM-4R/
E1-Ubal
4
User I/O and/or INL
Redundancy
Satellite buffering
2.048 Mbps
per port
ITU-T G.703
unbalanced
interface
109
Modular Node Design
SDM-8/V.11
The SDM-8/V.11 module is a synchronous I/O module providing an
eight-port V.36 interface for a user I/O device. V.36 is an ITU-T
standard for interfacing at data rates greater than 19.2 kbps. Data rates
for the SDM-8/V.11 can range from 1.2 kbps to 2.048 Mbps. The
module also supports EIA RS-449, RS-530, and X.21 interfaces.
SDM-8E/V.11
The SDM-8E/V.11 module is an eight-port enhanced V.11 module
that supports INLs in addition to user I/O devices.
SDM-8/V.35
The SDM-8/V.35 module provides an eight-port V.35 interface for
user I/O devices with rates ranging from 1.2 kbps to 2.048 Mbps.
ITU-T standard V.35 is similar to V.36 in that it describes a highspeed electrical interface.
SDM-8E/V.35
The SDM-8E/V.35 module is an eight-port enhanced V.35 module
that supports INLs in addition to user I/O devices.
SDM-8/V.24
The SDM-8/V.24 module provides an eight-port V.24 interface for
user I/O devices with data rates ranging from 0.3 to 38.4 kbps. V.24 is
the ITU-T definition for interchange circuits between data terminals
and data communications equipment. SDM-8/V.24 also supports an
EIA RS-232 interface, a set of standards specifying the electrical
interface between computers, terminals, and modems.
SDM-4R/V.11
The SDM-4R/V.11 module is a four-port enhanced V.11 module that
supports INLs in addition to user I/O devices and also provides
redundancy.
110
Modular Node Design
SDM-4R/V.35
The SDM-4R/V.35 module is a four-port enhanced V.35 module that
supports INLs in addition to user I/O devices and also provides
redundancy.
SDM-4R/E1-Bal
The SDM-4R/E1-Bal module provides a four-port interface for a user
I/O device and/or an INLwith a data rate of 2.048 Mbps. The module
complies with ITU-T G.703 standards for balanced 2.048-Mbps
interfaces. In addition, the module provides redundancy. Unlike the
E1M module, SDM-4R/E1-Bal does not provide G.704 framing.
RT
M-
12
ON STB FA
L Y IL
1
2
SDM-4R/E1-Ubal
The SDM-4R/E1-Ubal module provides a four-port interface for a
user I/O device and/or an INLwith a data rate of 2.048 Mbps. The
module complies with ITU-T G.703 standards for unbalanced 2.048Mbps interfaces. In addition, the module provides redundancy.
3
4
LO RE
C M
5
6
7
8
LO RE
C M
9
10
11
Remote Termination Module
The Remote Termination Module (RTM) provides a network access
point for AD-7 and AD-3 devices. The RTM allows these devices to
communicate with an ST node at distances up to 18,000 feet without
the use of a repeater. Figure 45 illustrates the front panel of the RTM.
12
LO RE
C M
P1
-1
2
The RTM is equipped with a two-wire U-interface (physical layer
only) that complies with electrical and layer 1 requirements of ANSI
T1.601-1992. (The RTM is not designed to connect to ISDN I.430
leased services.) The RTM can interface with up to 12 independent
access devices via a single RJ48M 50-pin connector.
The RTM operates in line termination mode while the access device
operates in network termination mode. Function control signals are
transparently transported end to end.
An out-of-band supervisory channel (16 kbps) between the RTM and
the access device is used to exchange configuration, management, and
maintenance information between a network administrator and the
remote access device.
Table 19 summarizes RTM specifications.
Figure 45.
Remote Termination
Module
111
Modular Node Design
Table 19. Remote Termination Module Specifications
Type
RTM-12
Ports
12
Support
Channel Data Rates
Compliance
Two-wire
U-interface for
AD-3 and AD-7
From 150 bps to 128
kbps
ANSI, ITU-T, and
2B1Q interface
specifications
Server Modules
The ST network server modules provide appropriate switching
technology and network services for the traffic on your network. Since
server modules are completely independent of I/O interfaces and
transmission facilities, the management and control of the facilities are
effectively separated from the type of traffic that uses the facilities.
Table 20 describes the server modules currently available.
Table 20. Server Modules
Module
Description
FSM
Frame Server Module: frame switching engine that statistically
multiplexes frame relay and HDLC data streams
SGM
Subrate Groomer Module: multiplexes and demultiplexes proprietary
subrate aggregate format (SAF), terminates AD-10
ASM
Application Server Module: a Digital Signal Processor (DSP)-based
module that accepts downloaded application software such as voice
compression and X.50
DSM
D-Channel Server Module: supports PBX networking functionality by
interpreting message-oriented common channel signaling (CCS)
protocols that request call setup and teardown
LGM
LINK/+ Gateway Module: provides an interface between an ST
network and a LINK/+ Family network, creating an integrated hybrid
network
Servers are shared among I/O modules and can reside locally in the
same node with the I/O or in another node. The latter method, referred
to as a remote server, is an extremely cost-effective alternative. The
ST node transports the data for access to the remote server as either
subrate TDM or N x 64 kbps TDM.
Server configuration is flexible enough to allow you to direct one
server's output to another server's input. This type of configuration,
known as cascaded servers, enables you to provide services on top of
existing services instead of installing additional circuitry at additional
cost. For example, you can transport HDLC or frame relay traffic
across X.50 TDM or AD-10 TDM channels. In the case of the X.50,
112
Modular Node Design
data travels from a T1M to an ASM and then to an FSM. In the case of
the AD-10, data travels from an SGM to an FSM.
Redundancy is accomplished through a resource pool in which similar
server modules share the load. If a module within a pool fails, the load
is automatically redistributed among the remaining modules.
Redundancy is provided by adding modules to the pool. All modules
are online and available for service.
FS
M-
64
Frame Server Module
The Frame Server Module (FSM) is an application processor based on
the Intel i960 RISC processor. With throughput of 8 kilopackets per
second, the FSM has virtual ports for access from I/O modules.
Figure 46 illustrates the front panel of an FSM.
ON STB FA
L Y IL
AC
T
OO
S
H
M
L
The FSM processes and switches both high-level data link control
(HDLC) and synchronous data link control (SDLC) frames and frame
relay packets. The FSM uses data link connection identifiers (DLCIs)
to route the packets via virtual channels. The DLCI is the frame relay
virtual circuit number corresponding to a particular destination. Each
FSM can support 1,024 DLCIs (up to 1,024 DLCIs per virtual port).
The FSM performs the following functions:
q
q
q
q
q
q
Transports Layer 2 packet-mode data for such applications as LAN
internetworking
Statistically multiplexes HDLC (including SDLC) and frame relay data.
Removes idle flags from HDLC data streams prior to transport for
bandwidth efficiency and then reinserts them at the remote end.
Transports serial port control functions via V.120 encapsulation
Generates cyclic redundancy checking (CRC)
Identifies and routes DLCI as part of frame relay port connection
Monitors buffer utilization to identify heavy traffic and a potential
congestion problem
In addition, the FSM complies with ANSI standards and ITU-T
recommendations for frame relay.
Figure 46.
Frame Server Module
113
Modular Node Design
There are two types of FSMs: FSM-64 and FSM-16. The FSM-64 has
64 virtual ports and a 4-Mbps throughput. The FSM-16 has 16 virtual
ports and an 8-Mbps throughput. Table 21 summarizes FSM-64 and
FSM-16 specifications.
Table 21. Frame Server Module Specifications
Type
FSM-64
Ports
64
SG
M-
Support
•
•
1
ON STB FA
L Y IL
AC
T
OO
S
H
•
M
L
FSM-16
16
•
•
•
Throughput
Maximum
DLCIs per
port: 1,024
Maximum
DLCIs per
module:
1,024
Maximum
bypassed
channels and
DLCIs per
module:
1,024
•
Maximum
DLCIs per
port: 1,024
Maximum
DLCIs per
module:
1,024
Maximum
bypassed
channels and
DLCIs per
module:
1,500
•
•
•
•
•
Maximum per
port: 2.048
Mbps
Maximum per
module:
4.096-Mbps,
full-duplex
access rate
Maximum 64byte packets
per second:
8,000
Compliance
ANSI, ITU-T for
frame relay
Maximum per
port: 2.048
Mbps
Maximum per
module:
8.192-Mbps,
full-duplex
access rate
Maximum 64byte packets
per second:
8,000
Since each ST-1000 node can support up to 32 FSMs, you can build
large packet networks. A node containing at least one FSM represents
an access point to the packet subnetwork.
Subrate Groomer Module
Figure 47.
Subrate Groomer Module
114
The Subrate Groomer Module (SGM) multiplexes and demultiplexes
channels below 56 kbps to and from an efficient proprietary subrate
format. Up to 512 subrate channels and/or aggregates can be
terminated at a node; but only one SGM is required in a node for
subrate multiplexing. Figure 47 illustrates the front panel of the SGM.
Modular Node Design
The SGM accepts low-speed data in subrate channel format. Data is
multiplexed with other low-speed channels, resulting in a subrate
aggregate with a bandwidth of 64 kbps. The subrate aggregate
information is then routed as N x 64 kbps TDM traffic across the
network. Up to 8,000 channels can be handled between termination
and bypass.
In order for the AD-10 to interface with the network, the ST node
must be equipped with an SGM operating in access groomer (AG)
mode. The SGM/AG provides additional services to transport and
cross connect the AD-10 subrate voice and TDM channels. An SGM
can terminate up to 32 AD-10 trunks. Additional SGMs can be added
to terminate up to 256 AD-10s per ST node. Output from the module
consists of subrate aggregate formats that combine and transport
subrate channels through the ST network as 64-kbps data using a
proprietary format.
Intermediate nodes that do not terminate or reroute the information in
the subrate aggregate do not require an SGM. At termination, the
subrate aggregate data is demultiplexed back to subrate channel
format.
Since one SGM module supports subrate capacity of an entire node,
additional SGMs are only necessary to increase the number of AD-10s
being terminated. Transfer to and from the module occurs across the
backplane bus.
The SGM performs the following key functions:
q
q
q
q
q
q
Synchronizes aggregates
Extracts subrate channels
Cross connects aggregates
Packs subrate channels into 64-kbps aggregates
Provides out-of-band signaling for control functions of subrate channels
Interfaces AD-10 access devices
There are two types of SGMs: SGM-1 and SGM-1 19.2K. The SGM-1
supports 56-kbps and 64-kbps AD-10 aggregate speeds. The
SGM-1 19.2K supports 19.2-kbps and 64-kbps AD-10 aggregate
115
Modular Node Design
speeds. Both modules support subrate aggregate formats at 64 kbps.
Table 22 summarizes SGM specifications.
Table 22. Subrate Groomer Module Specifications
Type
SGM-1
AD-10
Aggregate
Speed
56 kbps
and
64 kbps
AS
16
MT
OO
S
H
M
•
•
•
•
ON STB FA
L Y IL
AC
Support
SGM-1
19.2K
Carries up to 512 subrate aggregate formats at
64 kbps
Terminates up to 16 AD-10 trunks with
bandwidth contention on and up to 32 AD-10
trunks with bandwidth contention off
Terminates up to 512 TDM subrate channels
Bypasses up to 8,000 TDM subrate channels
19.2 kbps
and
64 kbps
L
When performing subrate groomer functions, the SGM-1 module and
the SGM-1 19.2K module can be redundant to each other. When
performing AD-10 access groomer mode functions, only the same
module type can be redundant to each other.
Application Server Module
The Application Server Module (ASM) is a server module
programmed to process specific applications within an ST node.
Because the ASM has no direct interfaces, it relies on SDM, T1M, or
E1M modules or on AD-3, AD-7, or AD-10 access devices for I/O
connections. Output consists of subrate aggregate formats that
combine and transport subrate and compressed voice channels to the
collocated SGM module, which is required in a node that contains an
ASM. Figure 48 illustrates the front panel of the ASM.
The ASM is based on digital processing engines (DPEs) that accept
downloaded application software from the Nodal Control Processor. In
this way, network managers can quickly and efficiently implement
new applications as they are developed, while reducing the number of
modules needed.
Figure 48.
Application Server Module
116
There are three types of ASMs: ASM-16, ASM-16A, and ASM-16C.
Through the ASMs, capabilities such as Code Excited Linear
Prediction/Adaptive Transform Coding (CELP/ATC) voice
compression, ADPCM voice compression, and X.50 multiplexing are
Modular Node Design
made available on the network. The ASM-16 supports CELP/ATC.
The ASM-16A can support ADPCM and X.50 simultaneously. The
ASM-16C can support CELP/ATC, ADPCM, and X.50
simultaneously.
CELP/ATC Capability
With Code Excited Linear Prediction (CELP) software, the ASM uses
an algorithm that compresses PCM voice to very low rates while
maintaining high voice quality. CELP compression is available at rates
of 5.33, 8, and 9.6 kbps. With Adaptive Transform Coding (ATC)
software, the ASM uses an algorithm that performs high-quality voice
compression at rates between 7.47 to 32 kbps.
The ASM has echo cancellation compliant with ITU-T G.165 for nearend echoes delayed by 0 to 32 milliseconds. The ASM accomplishes
fax compression via Group III fax support at 4.8, 7.2, and 9.6 kbps
with auto fallback.
ADPCM Capability
With Adaptive Differential Pulse Code Modulation (ADPCM)
software, the ASM uses an algorithm that compresses PCM voice
while maintaining high voice quality. ADPCM compression is
available at rates of 31.73 kbps and 36 kbps. The rate of 31.73 kbps
allows the transport of two ADPCM voice channels in a 64-kbps time
slot between ST nodes. The rate of 36 kbps is used for connection to a
LINK/2+ ADPCM circuit.
The algorithm used for both ADPCM coding rates is that of ANSI
T1.302 and T1.303. The implementation passes the relevant ANSI
ADPCM test vectors. Since the ADPCM algorithm incurs very little
delay, no echo cancellation is provided.
X.50 Capability
ITU-T standard X.50 defines the parameters of a subrate multiplexing
scheme for the international interface between synchronous data
networks. When equipped with X.50 capability, a node can provide
X.50 subrate channel multiplexing, cross connection, and grooming.
An ASM with X.50 software can multiplex any local or remote
subrate channel onto any X.50 facility. The X.50 facility can carry two
117
Modular Node Design
19.2-kbps signals, five 9.6-kbps signals, ten 4.8-kbps signals, or
twenty 2.4-kbps signals. Speeds can be mixed.
The module can also cross connect any X.50 subrate channel from any
local or remote X.50 facility to any other local or remote X.50 facility.
The X.50 software supports Division 2 and Division 3 of the ITU-T
X.50 recommendation.
The ASM has 16 DPEs. There can be up to four X.50 facilities per
DPE and up to 32 facilities per module. A single ASM supports as
many as 640 X.50 subrate channels. Table 23 summarizes ASM
specifications.
DS
M-
1
ON STB FA
L Y IL
AC
T
OO
S
H
Table 23. Application Server Module Specifications
Type
Function
Support
Compliance
ASM-16
ASM-16C
CELP/ATC
•
•
Maximum per DPE: 1
Maximum T1/E1 time slots per
module: 16
ITU-T G.165
echo
cancellation.
Full V.29,
4.8, 7.2, 9.6kbps Group
III fax rate
ASM-16A
ASM-16C
ADPCM
•
•
Maximum per DPE: 2
Maximum T1/E1 time slots per
module: 32
ANSI T1.302
and T1.303
ASM-16A
ASM-16C
X.50
•
•
•
Maximum facilities per DPE: 4
Maximum facilities per module: 32
Maximum subrate channels per
module: 640
ITU-T X.50
M
L
D-Channel Server Module
The D-Channel Server Module (DSM) supports PBX networking
functionality. The DSM allows an ST node to interpret the DPNSS or
QSIG common channel signaling (CCS) protocols used by PBXs to
request call setup and teardown. The DSM also transports
supplementary service messages from PBX to PBX, allowing effective
use of advanced PBX services such as call diversion, call waiting, and
call conferencing. Figure 49 illustrates the front panel of the DSM.
Figure 49.
D-Channel Server Module
118
The DSM communicates with a PBX via the D-channel, which is a 64kbps time slot of a T1M or E1M I/O port. The D-channel carries the
signaling information. The other time slots are B-channels that carry
user data. The D-channel connection between the PBX and the DSM is
carried as a TDM channel from the I/O module to the DSM.
Modular Node Design
The Inter-DSM Communications Port (IDCP) of the DSM provides
DSM-to-DSM communications using packet connections. The packet
connections are carried in the ST packet band. The IDCP is shared by
all the D-channels supported by a DSM.
Via a virtual port connection between the DSM and the D-channel, the
DSM interprets the D-channel messages for connection origination
and termination. Based on received connection messages, the DSM
can route the B-channels to a local or remote PBX interface. The DSM
can distinguish between requests for data calls and requests for voice
calls, which can be transported as compressed voice or PCM voice.
Supplementary service messages are passed from DSM to DSM
through the packet channel and are shared with user data.
LG
M-
2
ON STB FA
L Y IL
AC
T
A DSM can support one protocol at a time: either DPNSS or QSIG.
Each DSM can process up to 16 D-channels, including a mix of T1
and E1 facilities, interconnecting 16 PBXs. Table 24 summarizes
DSM specifications.
LO
S1
RO
S1
LO
S2
RO
S2
Table 24. D-Channel Server Module Specifications
Type
DSM-1
Support
•
•
Up to 16 D-channels
from a maximum of 16
PBXs
IDCP for DSM-to-DSM
communications
Compliance
DPNSS: British Telecom BTNR
188 for Digital Private Network
Signaling System No. 1
QSIG: ETSI 300 170, 300 172,
and 300 239
LINK/+ Gateway Module
The LINK/+ Gateway Module (LGM) provides an interface between
an ST network and a LINK/+ Family network, creating an integrated
hybrid network. Figure 50 illustrates the front panel of the LGM.
The LGM resides in an ST node and provides seamless connectivity to
a LINK/+ node. (A LINK/+ node can be a LINK/2+, miniLINK/2+,
microLINK/2+, entréeLINK/+, or LINK/100+ node). The LGM can
process two ILC aggregate format (IAF) streams from a LINK/+ node
to an ST node. The IAF stream is a LINK/+ proprietary data link that
can originate from a LINK/2+ ILC or ILQ module, from an
entréeLINK/+ ILC module, or from a LINK/100+ DLC module.
The IAF stream enters an ST node as a bundle of DS0s on a T1M or
E1M module, as an SDM channel, or via any other module capable of
Figure 50.
LINK/+ Gateway Module
119
Modular Node Design
transporting an N x 56 kbps or N x 64 kbps TDM stream (such as an
RTM connected to an AD-3 or AD-7). The IAF may bypass several
ST nodes before it is terminated on an LGM. The LGM then performs
the following key functions:
q
q
q
Demultiplexes the IAF
Receives and interprets the connection and supervisory information from
the IAF stream and, if necessary, reformats and transfers the
information to the NCP
Formats the LINK/+ data and control information into ST format for
transmission through the ST network or termination at an ST node
The LGM can also reformat ST data and commands into LINK/+ data
and commands. To build IAFs, the LGM receives ST-formatted data
from the ST bus and interprets the connection and supervisory
information. The LGM reformats the ST data and control information
into LINK/+ format and then multiplexes the channel data into IAFs.
The IAFs enter a T1M, E1M, or SDM for transmission to a LINK/+
node.
Table 25 summarizes LGM specifications.
Table 25. LINK/+ Gateway Module Specifications
Type
LGM-2
Support
•
•
•
•
•
•
•
•
120
Minimum throughput per module: 4.096 Mbps
IAFs per module: 2
Maximum rate per IAF: 2048 kbps
Maximum ARQ supervisory bandwidth:
- Per module: 19.2 kbps
- Per IAF: 9.6 kbps
Maximum channels:
- Per module: 416
- Per IAF: 208
Number of superrate single channel formats (SCFs): 416
Number of subrate aggregate formats (SAFs) per module: 48
LINK/+ revision levels:
- LINK/2+ releases 5 and later (including miniLINK/2+ and
microLINK/2+ nodes)
- LINK/100+ release 3.04 and later
- entréeLINK/+ release 3 and later
Modular Node Design
Internetworking Modules
Internetworking modules, commonly referred to as independent
routing processors (IRPs), can reside in the ST-1000. The modules
provide multiprotocol routing and standards-based intelligent bridging.
While offering direct connections to Ethernet, Token Ring, and FDDI
local area networks (LANs), the connections can also be remote across
wide area networks (WANs) using a broad range of wide area
protocols and network services: public X.25 network access, ISDN
access, SMDS network access, public frame relay access, private
frame relay switching, and dial backup. Additionally, the Independent
Cell Processor (ICP) integrates ATM access into the ST platform,
providing high-speed transport between sites for a variety of LAN and
SNA data over ATM. Table 26 summarizes the internetworking
modules.
Table 26. Internetworking Modules
Module
Description
IEEE 802.3/
Ethernet II
Interfaces up to four Ethernet LANs complying with the
IEEE 802.3 standard
IEEE 802.5/
Token Ring
Interfaces up to two Token Ring LANs complying with the
IEEE 802.5 standard using shielded or unshielded twisted-pair
wiring
FDDI
Connects up to two pairs of single-mode or multimode fiberoptic cables for connection to 100-Mbps fiber-optic rings
V.35
Connects up to four separate wide area network V.35 serial
data links
V.11 (X.21)/
MIL 188
(RS-449)
Connects up to four separate wide area network V.11/RS-449
serial data links
ISDN/BRI
Connects to an ISDN service provider and to a V.11/RS-449 or
V.35 wide area network
HSSI
When in DTE mode, supports full-duplex digital serial data at
rates from 56 kbps up to DS3 (44.736 Mbps) or SONET STS-1
(51.84 Mbps). When in DCE mode, the HSSI IRP can be used
as an interface to another HSSI IRP to interconnect two
collocated ST-1000 nodes.
Multi-Interface
WAN (MIW)
Provides four serial ports that can be configured individually for
a specific physical interface, such as V.28 with V.54, V.35 with
V.54, V.11 with V.54, X.21, and MIL-STD-188-114A (RS-449)
ATM ICP
Allows LAN-originating data to be sent across a public ATM
service at 155 Mbps
121
Modular Node Design
Cable Management
Conveniently, all module cables are accessible from the front of an ST
switching node's chassis. Each cable, connected from the front of the
appropriate module, is neatly groomed and directed through the
chassis to the rear of the unit.
An overview of cable management for the Nodal Control Processor
and the I/O interface modules follows.
Cables from the NCP front panel connectors interface with local area
networks, Craft Person Station terminals, modems, station clocks, and
external alarm indicators. Cables are deftly routed through the cable
space beneath the module assembly. Cable connectors are inserted into
the proper NCP panel connectors. The free end of the cables are then
routed and connected to the external device, and the cables can be
dressed and tied.
I/O Interface Modules
I/O modules may require distribution panels, which provide industrystandard physical and electrical connections. As a result, no special
cables are required between the distribution panel and the user
equipment. Also, the panels eliminate the stress on the chassis
bulkhead and the clutter of adapter cables common in rear-entry
systems. The number and position of distribution panels depend on the
configuration of the node.
Cables can be up to 25 feet in length, offering the option of locating
the panels in a separate cabinet. A distribution panel provides four
physical connections. All panel connectors are native. For example, a
V.36 interface is presented on a 37-pin connector and a V.35 interface
is presented on a Winchester connector. The panel also can be
optioned for DTE or DCE on each port, therefore saving on the
number of cables to support each site.
122
Modular Node Design
T1M/E1M, RTM
A 50-pin telco cable is plugged into the connector on the front of each
T1M-4, E1M-4, and RTM-12 module and is secured by tightening the
screws mounted on the connector. The cable is routed between the
fingers of the cable management bracket and through the space
beneath the module assembly. The open end of the cable is used
directly by the user or is plugged into the rear connector of the
distribution panel where the connector screws are tightened to secure
the cable head.
The E1M-2/Ubal module uses two BNC connectors per port. For each
port, one connector receives data and the other connector transmits
data.
The E1M-2/Bal module uses one 8-pin modular connector.
SDM
Two high-density 100-pin connectors are located on the front of each
SDM-8 module. These connectors support up to four physical
interfaces each. The 100-pin cable is attached to these connectors and
is secured with locking screws. The cable is located vertically
downward between the fingers of the cable management bracket and
through the cable space beneath the module assembly.
The open end of the 100-pin cable is placed into the rear 100-pin
connector of the distribution panel, and the end connector screws are
tightened to secure the cable. Modules are connected to the cable
management shelf through these cables.
The SDM-4R/V.11 and SDM-4R/V.35 modules use one high-density
100-pin connector.
The SDM-4R/E1-Bal module uses two 8-pin connectors per port. For
each port, one connector interfaces the E1 line and the other connector
monitors the E1 line.
The SDM-4R/E1-Ubal module uses two coax connectors per port. For
each port, one connector receives data and the other connector
transmits data.
123
Glossary
AD. See Synchrony AD.
adaptive differential pulse code modulation (ADPCM)
American National Standards Institute (ANSI) standard for digitizing voice
signals. By using a method of modulation in which only the difference between
signal samples is coded, ADPCM requires only 32 kbps and produces voice
quality that is not perceptibly lower than that of 64-kbps PCM digitization.
adaptive transform coding (ATC)
A pulse code modulation algorithm that compresses voice to low rates while
maintaining high voice quality.
address
Coded representation (usually numbers) for origin or destination. Every element
of a network has a unique address.
ADPCM
See adaptive differential pulse code modulation.
alarm
A message or signal that alerts a network user, operator, or hardware/software
agent of traffic congestion, electrical power loss, device failure, security breach,
and other types of warning conditions.
alternate mark inversion (AMI)
A pulse transmission scheme that uses alternating polarities in the pulse train.
AMI
See alternate mark inversion.
Application Server Module (ASM)
The ST server module programmed to process specific applications within an
ST node. Capabilities of the ASM include CELP/ATC, ADPCM, and X.50.
AR
See Synchrony AR.
125
Glossary
ARQ
See automatic repeat request.
ASM
See Application Server Module.
Asynchronous Transfer Mode (ATM)
Local area network/wide area network (LAN/WAN) scheme using 53-byte
fixed size cell relay transport technology, running at speeds of 150 Mbps and
up.
ATC
See adaptive transform coding.
ATM
See Asynchronous Transfer Mode.
attenuation
The loss of a signal's power as it passes through a medium. Generally, the level
of attenuation is a function of the length of the medium and is usually expressed
in decibels (dB).
automatic repeat request (ARQ)
A family of protocols for the acknowledgment of the successful receipt of
transmitted blocks. Communications between nodes, including channel
connect/disconnect requests, alarm notifications, and commands from the
Synchrony Network Management System are transmitted through the ARQ
band of an internodal link (INL).
B-channel
A 64-kbps time slot of a T1M or E1M I/O port that carries user data and is
routed by the D-Channel Server Module (DSM) to a local or remote PBX
interface.
B8ZS
Bipolar with eight zeros substitution. A modification of the alternate mark
inversion encoding scheme used to avoid possible loss of synchronization by
the receiver due to the lack of signal transitions when long sequences of zeros
occur. Nondata transitions are inserted into the transmission stream so that no
more than seven zeros occur in a row.
backbone
A macronetwork used for connection between subnetworks or clusters of users.
126
Glossary
backward explicit congestion notification (BECN)
A status flag in the header of a frame relay packet. The flag indicates that there
is congestion within the Synchrony network. See also forward explicit
congestion notification (FECN).
balanced circuit
A network-terminated circuit whose impedance balances the impedance of the
line so that the return loss is negligible. Twisted-pair cable is usually balanced
in that the two wires have the same references to ground potential and the
current in each is 180 degrees out of phase, thereby canceling cross
interference.
BBRAM
Battery backed-up RAM.
Bc
Committed burst. The maximum amount of data that a frame relay network
agrees to transfer over a measurement interval (T).
Be
Excess burst. The maximum amount of uncommitted data that a frame relay
network attempts to transfer over a measurement interval (T).
BECN
See backward explicit congestion notification.
BER
See bit error rate.
bit error rate (BER)
The ratio of received bits that are in error (relative to a specific amount of bits
received). Usually expressed as a number referenced to a power of 10, for
example: 1 error in 105 bits is also referred to as a BER of 10-5.
BNP
See Synchrony BNP.
breathable bandwidth
Unreserved INL bandwidth available for use by either constant bit rate (CBR)
traffic or variable bit rate (VBR) traffic as needed, depending on certain
priorities defined and configured by the network manager. See also hard deck.
127
Glossary
bundle
A selected group of N x 64 kbps signals. Bundles are user defined during T1M
and E1M port configuration.
bus
In digital systems, a multiconductor parallel transmission link that connects a
group of related devices.
CCITT
Consultative Committee on International Telephony and Telegraphy. Formerly
an international organization that set standards for telephone and data
communications systems. The name of the organization has been changed to
International Telecommunications Union-Telecommunications Standardization
Sector (ITU-T).
CCS
See common channel signaling.
CELP
See code excited linear prediction.
channel
A single communications path connecting two or more ports in the network.
Channel and circuit are often used interchangeably; however, circuit can also
describe a physical configuration of equipment that provides a network
transmission capability for multiple channels.
channel service unit (CSU)
An interface to a common carrier's transmission facilities that ensures that
digital signals placed on the line are properly shaped and timed. Usually
combined with a data service unit (DSU).
CIR
See committed information rate.
clear to send (CTS)
In half-duplex data transmission, a signal sent from a modem to a DTE that
initiates data transmission after a request-to-send signal has been received by
the modem.
clock
An oscillator-generated signal that provides a timing reference for a
transmission link.
128
Glossary
code excited linear prediction (CELP)
A pulse code modulation algorithm that compresses voice to very low rates
while maintaining high voice quality.
committed burst size
The maximum amount of data that a frame relay network agrees to transfer
under normal operating conditions over a measurement interval (T).
committed information rate (CIR)
The user-specified rate at which a frame relay network guarantees to transfer
information under normal operating conditions.
common channel signaling (CCS)
Technique in which network control signals (for example, call request) are
separated from the associated voice or data path by placing the signaling from a
group of voice or data paths on a separate channel dedicated to signaling only.
connection
The communication link between two network elements.
control shelf
The shelf of an ST node that contains the Nodal Control Processor (NCP).
CPI
See Craft Person Interface.
CPS
See Craft Person Station.
Craft Person Interface (CPI)
An asynchronous interface at an ST node that provides access for the Craft
Person Station (CPS).
Craft Person Station (CPS)
A PC-based software station used to configure and diagnose network nodes.
CRC
See cyclic redundancy check.
CSU
See channel service unit.
CTS
See clear to send.
129
Glossary
cyclic redundancy check (CRC)
A basic error checking mechanism for link-level data transmissions. The data
integrity of a received frame or packet is checked using an algorithm based on
the content of the frame and is matched with the result included in a field
appended to the frame.
D-channel
A 64-kbps time slot of a T1M or E1M I/O port that carries signaling
requirements and allows the D-Channel Server Module (DSM) to communicate
with a PBX. The D-channel is time slot 24 for T1 ports and time slot 16 for E1
ports.
D-Channel Server Module (DSM)
The ST server module that supports PBX networking functionality by
interpreting the DPNSS or QSIG message-oriented common channel signaling
(CCS) protocols that request call setup and teardown. The DSM also transports
supplementary service messages from PBX to PBX.
DACS
See digital access and cross-connect system.
data circuit-terminating equipment (DCE)
The class of devices responsible for establishing, maintaining, and terminating a
data communications circuit. Also called data communications equipment. A
modem is an example of a DCE.
data link connection identifier (DLCI)
Used by the frame relay protocol, a 2-byte header that contains addressing and
status information.
data service unit (DSU)
A device that connects terminal equipment to digital communications lines.
data set ready (DSR)
A control signal from a modem indicating the modem is powered on and ready
to send and receive data.
data terminal equipment (DTE)
Communications devices that generate and receive the data traffic in a
communications system. They may also provide interfaces to users. Terminals
and computers are examples of DTEs.
130
Glossary
data terminal ready (DTR)
In an interface between devices, a signal set by a data terminal device to inform
a data circuit-terminating device that it is ready to participate in a
communications session.
DCE
See data circuit-terminating equipment.
DCS
See digital cross-connect system.
DDS
See digital data service.
default
A value supplied by the system when one is not supplied by the operator.
digital access and cross-connect system (DACS)
An AT&T term for a digital cross-connect system (DCS). See digital crossconnect system.
digital cross-connect system (DCS)
Switching/multiplexing equipment that permits per-channel DS0 (64 kbps)
electronic cross-connection from one T1 transmission facility to another.
digital data service (DDS)
A digital transmission service supporting speeds up to 56 kbps.
digital processing engine (DPE)
Used in reference to the Application Server Module (ASM). The ASM has 16
digital processing engines each capable of processing one CELP/ATC channel,
two ADPCM channels, or four X.50 aggregates.
DLCI
See data link connection identifier.
domain
A subgroup of a network consisting of selected network elements, such as nodes
and INLs, that may be administered as a unit.
DPE
See digital processing engine.
131
Glossary
DPNSS
Digital Private Network Signaling System. A common channel signaling
protocol developed by British Telecom and other United Kingdom PBX
suppliers. DPNSS is defined in BT Standard BTNR 188.
DS0
Digital signal level 0. Standard term for a 64-kbps digital telecommunications
signal or channel.
DS1
Digital signal level 1. Standard term describing the 1.544-Mbps digital signal
carried on a T1 facility or the 2.048-Mbps digital signal carried on an E1
facility.
DSM
See D-Channel Server Module.
DSR
See data set ready.
DSU
See data service unit.
DSX-1
Digital signal cross-connect level 1. Standard term for the set of parameters
used where DS1 digital signal paths are crossconnected.
DTE
See data terminal equipment.
DTR
See data terminal ready.
dynamic routing
Routing in which the routing tables and route assignments are updated
frequently and automatically, based on network load levels and changes to the
network.
E1
Ascom Timeplex nomenclature for a digital carrier facility used to transmit a
G.703 formatted digital signal (32 time slots) at 2.048 Mbps.
132
Glossary
E1M
The ST I/O module that provides a standard E1 interface between backbone
nodes, collocated nodes, or between a node and a user I/O device.
EIA
See Electronics Industry Association.
EIR
See excess information rate.
Electronics Industry Association (EIA)
An organization that sets standards concerning the physical layer of the OSI
model.
Erlang
An international dimensionless unit of the average traffic intensity during a
period of time. One erlang of traffic is equivalent to a single user who uses a
single resource 100% of the time.
ESF
Extended superframe format. A T1 framing standard that provides frame
synchronization and CRC. Frames consist of 24 bits as opposed to 12 bits for
standard superframe format.
Ethernet
A local area network (LAN) architecture developed by Xerox Corporation that
operates as 10 Mbps. Provided the basis for the IEEE 802.3 standard.
excess burst size
The maximum amount of uncommitted data that a frame relay network attempts
to deliver over a measurement interval (T).
excess information rate (EIR)
The user-specified maximum rate at which a frame relay network attempts to
deliver data over a measurement interval (T). Beyond this rate, frames are
discarded.
expansion shelf
A shelf used to increase the number of I/O or server modules in a node.
Express Switching
A methodology that dynamically allocates bandwidth between constant bit rate
(CBR) and variable bit rate (VBR) traffic and an architecture designed to
133
Glossary
guarantee prioritization of individual data streams. Also, a method of
consolidating LAN and legacy traffic on a single multiprotocol network.
FDDI
See fiber distributed data interface.
FECN
See forward explicit congestion notification.
fiber distributed data interface (FDDI)
A 100-Mbps fiber-optic local area network configured in a dual counter rotating
ring topology to support fault-tolerant cabling.
forward explicit congestion notification (FECN)
A status flag in the DLCI header of a frame relay packet. The flag indicates that
there is congestion in the external frame relay network. See also backward
explicit congestion notification (BECN).
four-wire
A four-wire circuit that uses two sets of one-way transmission paths, one for
each direction of transmission.
frame
In time division multiplexing (TDM) systems, a sequence of time slots each
containing a sample from one of the channels carried by the system. The frame
is repeated at regular intervals and each channel usually occupies the same
sequence position in successive frames.
frame relay
A network-level protocol defined in ITU-T Recommendation I.122
"Framework for additional packet mode bearer services." Frame relay combines
the statistical multiplexing and port sharing of X.25 packet switching with the
high speed and low delay of time division multiplexing and circuit switching.
Frame Server Module (FSM)
The ST server module that processes and switches both high-level data link
control (HDLC) and synchronous data link control (SDLC) frames and frame
relay packets.
framing
A control procedure used with multiplexed digital channels, such as T1 carriers,
whereby bits are inserted so that the receiver can identify the time slots that are
allocated to each subchannel.
134
Glossary
FSM
See Frame Server Module.
G.703
The ITU-T physical and electrical specification for interfaces at 64 kbps and
2048 Mbps.
G.704
The ITU-T specification for framing on a 2048-Mbps E1 facility.
gateway
A conceptual or logical network station that serves to interconnect two
otherwise incompatible networks, network nodes, subnetworks, or devices.
Gateways perform a protocol-conversion operation across a wide spectrum of
communications functions or layers. The LINK/+ Gateway Module (LGM)
provides a gateway between ST and LINK/+ nodes.
hard deck
The minimum guaranteed INL bandwidth, defined by the network administrator
in 64-kbps increments, available to constant bit rate (CBR) and variable bit rate
(VBR) traffic. See also breathable bandwidth.
HDLC
See high level data link control.
high level data link control (HDLC)
An ITU-T specified bit-oriented data link control protocol. Rather than control
characters, a specified series of bits is used for control information.
IAN
See Synchrony IAN.
inband signaling
Signaling that uses not only the same channel path as the voice traffic but also
the same frequency range (band) used for the voice traffic.
INL
See internodal link.
International Telecommunications Union-Telecommunications
Standardization Sector (ITU-T)
An international organization that sets standards for telephone and data
communications equipment. Formerly the Consultative Committee on
International Telephony and Telegraphy (CCITT).
135
Glossary
internet protocol (IP)
A protocol that provides for the transfer of data over a network or a set of
networks. Every IP datagram contains the 32-bit addresses of both the source
and destination hosts in the 20-byte IP header. The internet protocol is used by
the Synchrony Network Management System to communicate with ST nodes.
internodal link (INL)
A network trunk between two ST nodes that carries packet, TDM, or
supervisory traffic or a combination of the three.
IP
See internet protocol.
IP address
A 32-bit address used in networks utilizing the internet protocol to identify
nodes within the network.
ISO
International Organization for Standardization.
ITU-T
See International Telecommunications Union-Telecommunications
Standardization Sector (ITU-T).
jitter
In a digital pulse, small variations that cause distortion from the ideal.
kbps
Kilobits per second. One kilobit is equal to 1000 bits.
LAN
See local area network.
Left Expansion Module (LXM)
The common equipment module used in the ST-1000 to connect the intershelf
cable from the upstream shelf and the backplane bus of an expansion shelf.
LGM
See LINK/+ Gateway Module.
LINK/+ Gateway Module (LGM)
The ST server module that provides an interface between an ST network and a
LINK/+ Family network, creating an integrated hybrid network. See also
gateway.
136
Glossary
LMI
See local management interface.
local area network (LAN)
A data communications system that connects computers and peripheral devices,
all of which are situated within a localized area.
local management interface (LMI)
An optional set of management messages used to communicate status
information between the network and access devices in frame relay networks.
The LMI provides information on link status and virtual circuit status.
logical port
See virtual port.
loopback
Diagnostic procedure used for transmission devices.
LXM
See Left Expansion Module.
management information base (MIB)
A network information file that conforms to the simple network management
protocol (SNMP).
Mbps
Megabits per second.
MIB
See management information base.
MTBF
Mean time between failures.
N x DS0
Abbreviated terminology for any number of DS0-formatted 64-kbps digital
telecommunications signals. Also used to indicate a multiple of DS0 channels.
NCP
See Nodal Control Processor.
Nodal Control Processor (NCP)
The common equipment module that provides nodal intelligence, controls the
backplane, and performs clocking for an ST node.
137
Glossary
OSI model
Open Systems Interconnection model. OSI is a seven-layer logical structure
defined by the ISO that is used to develop the interface and protocol standards
to enable any two OSI-compliant devices to communicate. The layers are
physical, data link, network, transport, session, presentation, and application.
Systems designed using the OSI model are referred to as open systems.
out-of-band signaling
Signaling that uses the same channel path as the voice traffic but is in a
frequency band outside that used for the voice traffic. In digital systems, out-ofband signaling may take the form of an allocated bit position or a dedicated
channel or time slot.
packet
A unit of data that always has source and destination address and other control
information.
packet band
An N x 64 kbps data stream that carries packet data.
packet switching
A data transmission technique whereby user information is segmented and
routed in discrete data envelopes called packets, each with its own appended
control information for routing, sequencing, and error checking. Allows a
communications channel to be shared by many users, each using the circuit only
for the time required to transmit a single packet.
PBX. See private branch exchange.
PCM. See pulse code modulation.
permanent virtual circuit (PVC)
A virtual connection between user devices through the network. This
connection is defined at subscription time, as opposed to a dialed-up or
switched connection.
phasor
A buffer space that holds enough data to adjust for small discrepancies between
the system and receive clocks.
physical port
A physical interface that connects modules to user equipment.
138
Glossary
port
See virtual port and physical port.
private branch exchange (PBX)
A telephone exchange on a user's premises that provides switching services for
local extensions and access to the public telephone network.
protocol
A set of rules and conventions that communicating participants must follow to
exchange information.
pulse code modulation (PCM)
A process in which a signal is sampled, and the magnitude of each sample with
respect to a fixed reference is quantized and converted into a digital signal.
PVC
See permanent virtual circuit.
QSIG
A common channel signaling (CCS) protocol that serves as the standard for
signaling at the Q reference point between two transit PBXs. Based on ITU-T
ISDN Q.931.
Remote Termination Module (RTM)
The ST I/O module that provides a network access point for the AD-7 and AD3 devices.
request to send (RTS)
An RS-232 modem interface signal sent from data terminal equipment (DTE) to
the modem on pin 4 indicating that the DTE has data to send. Employed in a
half-duplex transmission mode.
Right Expansion Module (RXM)
The common equipment module used in the ST-1000 to expand the backplane
add bus from one shelf to the next or to loop data from the add bus to the drop
bus of a single-shelf node.
route
The path between destinations in a network.
RS-232
An EIA-recommended standard that defines the interface between data terminal
equipment (DTE) and data circuit-terminating equipment (DCE) employing
139
Glossary
serial binary data interchange and unbalanced signaling. (Comparable to ITU-T
V.24)
RS-422
An EIA-recommended standard that defines electrical characteristics of
balanced voltage digital interface circuits.
RS-423
An EIA-recommended standard that defines electrical characteristics of
unbalanced voltage digital interface circuits.
RS-449
An EIA-recommended standard that defines the general-purpose interface for
DTE and DCE employing serial binary data interchange, usually used for
synchronous transmissions. (Comparable to ITU-T V.36)
RTM
See Remote Termination Module.
RTS
See request to send.
Rx
Receive.
RXM
See Right Expansion Module.
SDLC
See synchronous data link control.
SDM
See Synchronous Data Module.
SGM
See Subrate Groomer Module.
shelf
A self-contained unit consisting of a backplane, multiple circuit modules,
distribution panels, power supplies, and a cooling system. An ST-1000 node can
contain from one to four shelves. An ST-20 node contains one shelf only.
simple network management protocol (SNMP)
Part of the TCP/IP protocol suite, SNMP operates above the transport layer in
140
Glossary
the OSI model and provides management data on network devices. The SNMP
protocol is implemented in the ST node to allow it to be monitored by the
Synchrony Network Management System.
SNMP
See simple network management protocol.
SONET
Synchronous optical network, a communications standard which specifies
characteristics of the fiber-optic communication medium and specifies the data
communication rates. The rates are usually specified as multiples of 51.84 Mbps
(OC-1). OC -3 is three times as fast as OC-1, and OC-12 is four times as fast as
OC-3. Specifications currently exist which exceed 2 Gbps.
ST node. See Synchrony ST.
stat mux
See statistical multiplexer.
statistical multiplexer
A device that permits a number of lower bit-rate devices to share a single higher
bit-rate transmission channel where the sum of the lower bit-rate devices is
greater than the bit rate of the shared line. Time slots are not preallocated for
devices but are assigned dynamically as data arrives from the lower bit-rate
devices.
subrate channel
A TDM channel with a rate of less than 56 kbps.
Subrate Groomer Module (SGM)
The ST server module that multiplexes and demultiplexes channels below 56
kbps to and from a proprietary subrate format.
synchronous data link control (SDLC)
A bit-oriented data link control protocol used by IBM as part of their SNA
network architecture.
Synchronous Data Module (SDM)
The ST I/O module that provides an interface from synchronous user data
operating at subrate (less than 56 kbps) and superrate (multiples of 56 or 64
kbps) speeds.
141
Glossary
Synchrony AD
Access devices that incorporate packetized data handling and circuit switching.
Models include the AD-10, AD-7, and AD-3.
Synchrony AR
Internetworking devices that provide high-performance multiprotocol routing
and standards-based intelligent bridging. Models include the AR-350, AR, and
AR-150.
Synchrony BNP
Branch access systems that offer frame relay and X.25 switching. Support serial
protocols including asynchronous, bisynchronous, Burroughs Poll/Select, and
many others. Models include the BNP-350 and the BNP.
Synchrony IAN
Branch data systems that consolidate LAN and legacy traffic onto a single wide
area network. Provide frame relay and X.25 packet switching, multiprotocol
routing, and standards-based bridging. Models include the IAN and the
IAN-150.
Synchrony Network Management System
The network management software product used to monitor, configure, and
control networks that include Ascom Timeplex products.
Synchrony ST
Circuit-based networking multiplexers and frame relay switches designed to
efficiently handle N x 64 kbps TDM and packet channels simultaneously. ST
nodes are available in two models: ST-1000 and ST-20. The ST-1000 also
functions as a router/bridge.
T
The fixed time interval over which the CIR and EIR are measured and on which
the Bc and Be are based.
T1
A digital carrier facility used to transmit a DS1 formatted digital signal (24 DS0
channels) at 1.544 Mbps.
T1M
The ST I/O module that provides a standard T1 interface between backbone
nodes, collocated nodes, or between a node and a user I/O device.
142
Glossary
T3
A digital carrier facility used to transmit 28 DS1 (T1) signals with an aggregate
rate of 44.736 Mbps.
TDM
See time division multiplexing.
time division multiplexing (TDM)
Interleaving digital data from many users onto one or two serial
communications links by dividing channel capacity into time slots.
token ring
A type of local area network in which all the devices are connected in the form
of a physical ring and messages are transmitted by allowing them to circulate
around the ring. A device can only transmit a message on the ring when it is in
possession of a control token. A single token is passed from one device to
another around the ring.
trap message
A message sent by any IP device to a network management system indicating
that an event of interest has occurred.
trunk
A dedicated aggregate telephone circuit connecting two switching centers,
central offices, or data concentration devices.
trunk group
A MIB entity that collectively defines voice compression configuration for a set
of circuits with a common range of termination points at a destination port.
Tx
Transmit.
unbalanced circuit
A mode of transmission where signals are sent on a single conductor with
transmitter and receiver sharing a common ground.
V.35
An electrical interface protocol for data transmission using 60-108 kHz group
bps circuits.
virtual circuit
A logical connection between two devices (used in frame relay applications). A
143
Glossary
dynamically variable network connection where sequential user data packets
may be routed differently. See also permanent virtual circuit (PVC).
virtual port
A logical interface to a server module identified by server type and arbitrary
port number. Virtual ports are dynamically allocated server module resources at
run time.
WAN
See wide area network.
wide area network (WAN)
A data communications network that uses common carriers to connect widely
separated systems or networks. Typically used to interconnect LANs.
X.25
A network-level protocol defined in ITU-T Recommendation X.25 that
specifies the interface between user data terminal equipment (DTE) and packet
switching data circuit-terminating equipment (DCE).
X.50
specifies the fundamental parameters of a multiplexing scheme for the
international interface between synchronous data networks.
X.50 aggregate
Used to refer to a single X.50 formatted data stream.
X.54
specifies the allocation of channels on international multiplex links at 64 kbps.
144
Index
A
Access Systems, Synchrony
AD, 82
AR, 94
BNP, 95
IAN, 95
overview, 81
AD Management, 47
AD Systems, 82
AD-10, 83
AD-3, 93
AD-7, 91
AD-10, 83
aggregate, 85
core module, 84
diagram of logical interface, 86
Expansion Data Module (EDM), 84
Hybrid Data Module (HDM), 84
modular architecture, 84
packet support, 88
physical description, 89
port capabilities, 87
specifications, 97
ST interface, 85
table of packet port speeds, 89
table of TDM port speeds, 87
table of user ports, 87
TDM support, 87
voice support, 88
voice/FAX (VFAX) module, 84
AD-3, 93
specifications, 98
AD-7, 91
ports, 92
specifications, 98
ST interface, 91
supervisory band, 92
table of port speeds, 92
Adaptive Differential Pulse Code Modulation (ADPCM),
117
Adaptive Transform Coding (ATC)
AD-10, 88
Application Server Module (ASM), 117
ADPCM, 117
Alarm Management, 48
Application Scenarios, 58
branch access, 66
campus, 67
frame relay switch, 61
international gateway, 68
PBX networking, 62
ST and LINK/+ DS0/X.50, 65
ST and LINK/+ gateway, 64
traditional, 58
voice/packet hybrid, 60
ADPCM capability, 117
CELP/ATC capability, 117
specifications, 118
X.50 capability, 117
AR Systems, 94
Asynchronous Transfer Mode Migration, 9
ATM Independent Cell Processor (ICP), 121
ATM Migration, 9
Automatic Network Discovery, 43
B
Backward Explicit Congestion Notification (BECN), 35
Billing and Accounting, 52
Bit Error Rate (BER), 33
BNP Systems, 95
Branch Access Application, 66
Bundle Management, 45
Bus Backplane, 76
C
CA-Ingres, 52
Cable Management, 122
Cabling, 79
Campus Application, 67
CBR Parameters, 33
Channel Profile, 32
facility characteristics, 33
hop counts, 33
management, 46
maximum allowable bit error rate, 33
priority, 33
satellite hops, 33
Chassis and Shelving, 77
145
Index
Circuit Bus, 76
Circuit Loopback, 49
Clock Fallback List, 38
Code Excited Linear Prediction (CELP)
AD-10, 88
Committed Burst Size (Bc), 34
Committed Information Rate (CIR), 34
Common Equipment Modules, 100
Connections, 26
diagnostics, 49
hierarchy of, 26
parameters, 32
types of, 32
Constant Bit Rate (CBR), 15
Cost Criteria, 36
CPS, 52
Craft Person Station (CPS), 52
Customer Support
Customer Support Center, 69
installation, 69
maintenance, 70
training and education, 70
D
D-Channel Server Module (DSM), 118
specifications, 119
Data Link Connection Identifier (DLCI), 22, 35
frame relay header format, 22
Dijkstra Algorithm, 36
Dynamic Bandwidth Allocation, 7, 20
hard decks, 20
E
E1 Module (E1M), 106
specifications, 107
Echo Cancellation, 88
ER-5, 56
Error Monitoring, 37
Ethernet II IRP, 121
Excess Burst Size (Be), 34
Excess Information Rate (EIR), 34
Express Switching Architecture, 6
146
F
Facility Characteristics, 33
Fault Management, 49
FDDI IRP, 121
Forward Explicit Congestion Notification (FECN), 35
Frame Relay Management, 47
Frame Relay Packet, 23
Frame Relay Switch Application, 61
Frame Server, 57
Frame Server Module (FSM), 22, 113
specifications, 114
H
Hard Decks, 20
Hop Counts, 33
HSSI IRP, 121
I
IAN Systems, 95
ICP, 121
IEEE 802.3 IRP, 121
IEEE 802.5 IRP, 121
Independent Cell Processor (ICP), 121
Independent Routing Processor (IRP) Modules, 77, 121
Information Management, 52
Input/Output Modules, 103
Integrated Frame Relay and CBR, 8
Internal Oscillator, 38
International Gateway Application, 68
Internetworking Modules, 77, 121
Internodal Link, 20
Internodal Link Management, 45
Interoperability, 3
IRP Modules, 77, 121
ISDN/BRI IRP, 121
L
Least-Cost Routing, 36
Left Expansion Module (LXM), 103
LINK/+ Gateway Module (LGM), 119
specifications, 120
LINK/+ Integrated Connectivity Systems, 57
ST compatibility, 10
Index
Loopback, 49
M
Master Clocking Nodes, 39
Measurement Interval (T), 34
MIW IRP, 121
Modular Architecture, 75
Modules, 18
Application Server Module (ASM), 19, 116
ATM Independent Cell Processor (ICP), 121
cable management, 122
common equipment, 18, 100
D-Channel Server Module (DSM), 19, 118
E1 Module (E1M), 18, 106
FDDI IRP, 121
Frame Server Module (FSM), 19, 113
HSSI IRP, 121
IEEE 802.3/Ethernet II IRP, 121
IEEE 802.5/Token Ring IRP, 121
Independent Cell Processor (ICP), 121
independent routing processors (IRPs), 77, 121
input/output (I/O), 18, 103
internetworking, 77, 121
ISDN/BRI IRP, 121
Left Expansion Module (LXM), 18, 103
LINK/+ Gateway Module (LGM), 19, 119
Multi-Interface WAN (MIW), 121
Nodal Control Processor (NCP), 18, 101
Remote Termination Module (RTM), 18, 111
Right Expansion Module (RXM), 18, 102
server, 19, 112
Subrate Groomer Module (SGM), 19, 114
Synchronous Data Module (SDM), 18, 108
T1 Module (T1M), 18, 104
table of, 75
V.11 IRP, 121
V.35 IRP, 121
Multi-Interface WAN (MIW), 121
N
Network Connections, 26
Network Management
AD management, 47
alarm management, 48
automatic network discovery, 43
billing and accounting, 52
bundle management, 45
channel profile management, 46
connection diagnostics, 49
fault management, 49
frame relay management, 47
icons, 43
information management, 52
internodal link management, 45
network topology map, 43
node diagnostics, 50
node management, 45
relational database, 52
routing table management, 47
security, 50
softload upgradability, 48
specifications, 42
subrate channel management, 46
superrate channel management, 46
topology management, 43
voice circuit management, 46
voice profile management, 46
workstations, 42
Network Partitions, 50
Network Topology Map, 43
Nodal Clocking, 38
clock fallback list, 38
dependent sources, 38
independent sources, 38
internal oscillator, 38
slave holdover mode, 38
Nodal Control Processor (NCP), 101
Node
diagnostics, 50
management, 45
NP-1000, 56
P
Packet Parameters, 34
Packet Subnetwork, 22
rate enforcement, 34
Parameters
CBR, 33
packet, 34
Partitions, 50
virtual private networks, 51
PBX Networking, 9
application, 62
Permanent Virtual Circuit (PVC)
defined, 22
packet configuration, 22
147
Index
Power Distribution, 78
Priority, 33
Private Branch Exchange Networking, 9
R
Rate Enforcement, 34
Relational Database, 52
Remote Termination Module (RTM), 111
specifications, 112
Right Expansion Module (RXM), 102
Router Bridge, 57
Routing
least-cost, 36
Routing Table Management, 47
S
Satellite Hops, 33
Security, 50
Server Modules, 112
Simple Network Management Protocol (SNMP), 43
trap-directed polling, 48
Slave Holdover Mode, 38
SNMS, 41
See also Network Management
Softload Upgradability, 48
Specifications
AD-10, 97
AD-3, 98
AD-7, 98
D-Channel Server Module (DSM), 119
E1 Module (E1M), 107
Frame Server Module (FSM), 114
LINK/+ Gateway Module (LGM), 120
Network Management, 42
Remote Termination Module (RTM), 112
ST-1000, 96
ST-20, 97
Subrate Groomer Module (SGM), 116
Synchronous Data Module (SDM), 109
T1 Module (T1M), 105
ST. See Synchrony ST
ST-1000 Node, 73
bus backplane, 76
cabling, 79
148
chassis and shelving, 77
diagram of shelves, 78
modular architecture, 75
power distribution, 78
specifications, 96
ST-20 Node, 80
specifications, 97
Subnetworks, 22
packet, 22
subrate, 24
Subrate Capability, 10
Subrate Channel Management, 46
Subrate Groomer Module (SGM), 22, 114
specifications, 116
Subrate Subnetwork, 24
Superrate Channel Management, 46
Switching and Transport Nodes, 18, 72
ST-1000, 73
ST-20, 80
Synchronization, 37
master clocking nodes, 39
nodal clocking, 38
Synchronous Data Module (SDM), 108
specifications, 109
Synchrony AD Systems, 82
AD-10, 83
AD-3, 93
AD-7, 91
comparison chart, 83
Synchrony AR Systems, 94
Synchrony BNP Systems, 95
Synchrony ER-5, 56
Synchrony IAN Systems, 95
Synchrony Network Management System (SNMS), 41
See also Network Management
Synchrony NP-1000, 56
Synchrony ST
application scenarios, 58
benefits, 13
features, 5
LINK/+ DS0/X.50 interworking application, 65
LINK/+ gateway application, 64
modules, 99
network architecture, 15
network elements, 17
network management, 41
nodes, 18, 72
Synchrony TX-3, 56
Index
T
T1 Module (T1M), 104
specifications, 105
Token Ring IRP, 121
Topology Management, 43
Traditional Application, 58
Trunk Groups, 32
TX-3, 56
U
V
V.11 IRP, 121
V.35 IRP, 121
Variable Bit Rate (VBR), 15
Virtual Packet Bus, 76
Virtual Private Networks, 51
Voice Circuit Management, 46
Voice Compression, 9
Voice Profile Management, 46
Voice Switching, 9
Voice/Packet Hybrid Application, 60
Upgradability, 48
149