SIP/SIMPLE as an overlay protocol for the Internet (Arup

SIP/ SIMPLE : A control architecture for the wired
and wireless Internet ?
Arup Acharya
Network Server Systems Software
Advanced Networking Services (On-Demand Innovation Services)
IBM T J Watson Research Center
sip:[email protected]
What is SIP (Session Initiation Protocol) ?
(Overview)
Session Initiation Protocol
SIP server
ƒ
•
SIP
signaling
An Internet signaling protocol for setting up multimedia sessions
‰
SIP server
SIP server
Mobility support – call control in 3G networks
o
Terminal / service mobility
RTP/UDP
voice packets
V
•
Uses (overlay) control network of SIP servers
‰
‰
‰
‰
•
‰
ƒ
independent of media type (voice, video)
Media Path (RTP/UDP) decoupled from signaling
Dynamic negotiation of device capabilities, media type
Message routing is application specific
o DNS-based
name@domain addressing
‰
•
V
Dynamic resolution of SIP URIs to device(s)
o Location-based
DNS enhancements for SIP service records & ENUM
VOIP
Telephony & Voice Mail
Unified Messaging
FindFind-MeMe-FollowFollow-Me
Call Center
Message syntax similar to HTTP
SIMPLE : SIP extensions to support Presence and IM
•
Pub/Sub mechanism
•
IM carried as signaling message payload
‰
Protocols
&
Technologies
Instant
Messaging
Presence
Video
IP TV
Collaboration
Real time media
Real
time media
protocols
(RTP)
protocols
(RTP)
And codecs
And codecs
Push
To
Talk
IMS (3G)
HTTP
HTTP
XML
XML
Registration
Subscription & Session
Notifications Negotiation
Push-to-talk on cell-phones
Internet Protocol (IP)
SIP : an end-to-end control protocol not so far present in the
Internet ?
ƒ
2
Network
Integration
with
WebWeb-portals
Client Desktop
Devices
Servers
SIP/SIMPLE
SIP/SIMPLE
IBM Global Services
Widespread adoption of SIP/SIMPLE
ƒ Enterprise Software vendors
s
i
k
AT&T, MCI, Earthlink, [Vonage, Packet8, …..]
r
o
Time Warner, Comcast
w
t ” vendors
ƒ “Networking
e
(Hosted) Covad, Verizon,…
n Nortel, Nokia, Lucent,….
Cisco,
l
o
r
t
Wireless providers
nƒ Emerging
? Infrastructure
o
Sprint/Nextel, Verizon Wireless,..
n
/c tiovendors
y
[Push-to-talk]
a uc
Sonus, NexTone, Antepo,..
l
r
3G (IMS)
e str
Open Source : SIPFoundry
v
o
n
e
o
Web portals : Yahoo, MSN, d
AOL
ƒ Peer-to-peer SIP
i rc
w
e
Earthlink SIPshare
t
d
e
Application Service
Providers
:
Webex
n
SOSIMPLE
n
u
r
e
Skype (proprietary)
t
n
Corporate IEnterprise IT/networks
ƒ Gaming Consoles
An
ƒ Wireline providers [consumer/ business]
-
-Microsoft,
IBM, Oracle, BEA,….
-
ƒ
-
-
ƒ
ƒ
-
-
ƒ
Sony Playstation announced
support for VoIP
-
3
© Copyright IBM Corporation 2005
Impact of SIP in the enterprise IT/ network infrastructure
ƒ
ƒ
ƒ
ƒ
Enterprise communication now runs on a common infrastructure of servers and data network
SIP servers adjunct to web servers / directories
Integrate web & SIP applications on (a) client desktops and (b) servers
►Web browsers can be expected to recognise SIP URIs
Communication applications are desktop based : voice/video, presence, instant messaging
Conferencing
Server
Proxy
IM Server
Web
server
Application
Enablement
Registrar
PSTN
gateway
Enterprise
directory
SIP
HTTP
SIP Infrastructure
IP-PSTN
Media gw
Ethernet / 802.11
IP Network (routers, switches..)
4
Demo scenario : Web page with ‘clickable’ SIP URIs
Click here
to call me
(SIP
recognised as
a first-class
protocol like
HTTP or mailto
without any
change to
browser code)
5
Impact of SIP : server-based networking
Telecom morphs to IT
Circuit-Switched
M
O
N
O
L
I
T
H
I
C
Services &
Applications
Call Control
integrated with
switching
hardware
Voice
Transport
SIP-based IP
Communications
Services, Applications & Features
(integration with business
processes)
APIs
Session Control : SIP servers
APIs
Common IP Network for both
voice and data
► Server platforms (instead of dedicated switching PSTN hardware)
► Control (session, call) implemented as server application software
6
Role of SIP in 3rd Generation mobile networks : IMS
IP Multimedia subsystem (IMS) in 3GPP is based on SIP
Call/session control and roaming via SIP
SIP client on cell-phones : SMS replaced by SIP-based IM
Call Session
ControlFunction
(CSCF)
SIP enabled
devices
Presence
SIP
Push-to-talk
IP Multimedia Core
IM
GPRS/EDGE/
WCDMA
GGSN
IP transport
Any SIP AS
Service enablers/
applications
7
Application
Servers
SIP Messages : Header + Body
►SIP Headers
►Message Body
►Captures best of both worlds?
– Efficiency of IP headers
– Flexibility of Application-layer
messages
8
UDP Header
INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/UDP sip-proxy.watson.ibm.com
From: Arup Acharya <sip:[email protected]>
To: Gordon Kerr <sip:[email protected]>
Call-ID: [email protected]
CSeq: 1 INVITE
Expires: 180
User-Agent: Cisco IP Phone/ Rev. 1/ SIP enabled
Accept: application/sdp
Contact: sip:[email protected]:5060
Content-Type: application/sdp
Content-Length : 124
v=1
o=V=C=IN IP4 9.2.91.243
t=m=video 4004 RTP/AVP 13 26
a=rtpmap:14 MPA/90000
SIP BODY
– Could be XML / SDP / text/..
(e.g Presence Subscriptions)
– Not (required to be)
interpreted hop-by-hop
IP Header
SIP HEADER
– Used for routing at SIP
servers
– Could be modified hop-by-hop
– Routing is application-specific
– Ok not to recognize a (new)
field
Possible impact on Internet-based services / architecture
ƒ A new de-facto control layer
SIP
based on SIP
SIP server
(control overlay)
Media
ƒ Server-based networking
ƒ “Interesting” services are derived
from this overlay network
PSTN
Media Sessions
(voice, video,..)
Instant
messaging
Presence
Event Notification
(pub/ sub)
Naming/
addressing
Location
based
Services
Mobility
Control
SIPSIP-based Primitives / Base Services
Registrar
Server
Proxy
Server
IM
Server
IM
Server
Presence
Server
Integration
with
DNS/ ENUM
SIPSIP-based Convergence layer
TCP/IP Network : Connectivity / Routing / Transport
9
Session
Border
Control
(firewalls)
Ongoing Research Project : Scaling SIP servers
SIP is multi-faceted; thus, potentially multiple server performance bottlenecks
ƒ Presence
ƒ Session Setup (voice/ video)
►Rate of subscription / notification requests
Registration
server
►Updates in presence information, including nonSIP sources
Redirect/ location
server
Application
Server
Registration
Session
setup
SIP proxy
SUBSCRIBE
NOTIFY
Presence
Information
RTP/UDP packets
(media)
ƒ
-SIP registrar
-Network login
(e.g. 3G)
- ..
Collaboration, e.g. conferencing
ƒ
Application
(Conference)
Server
Session
setup
Presence
server
Instant Messaging
►Number of messages
►Size of messages
Media
mixer
Instant
Message
IM Server
RTP/UDP
packets (media)
10
Joint work with E. Nahum, J.M. Tracey, Z.Y. Shae, X. Wang (IBM Research)
SIP on Wearable Devices (Linux WatchPad)
ƒ Linux WatchPad as a wearable control device
►
►
►
►
►
Interface always visible/ easily accessible
Receive phone calls on watch and decide how to respond
Move an ongoing call from a PSTN phone to cell phone
Receive IMs with yes/no responses
Subscription notifications : display as icons
ƒ Prototype completed, patent filed
11
Joint work with Wearable Computing Group (Stefan Berger, Chandra Narayanaswami)
Conclusions
ƒ Adoption of SIP across enterprise, service provider and mobile providers
effectively creating an Internet-wide overlay control network
ƒ Servers and software have a transformational role to play
► Shift from router-based networking to server-based “networking”
ƒ Is this the next step in the architectural evolution of the Internet ?
THANK YOU!
More information:
Contact : Arup Acharya, IBM TJ Watson Research Ctr
[email protected] / +1 914 784 7481
http://www.research.ibm.com/people/a/arup
Further details on SIP work in IBM Research:
http://www.research.ibm.com/people/a/arup/custom2.html
12
Research SIP Pilot + new components (application integration,
conferencing service)
SIP Conference
Manager
Application
Server (IM,
email, web,..)
Application
protocol
CONVEDIA
conferencing
hardware
SIP
control
RTP/UDP
Voice packets
(multimulti-party
connection)
connection)
SIP Proxy Server
SIP
SIP
Cisco 3640
SIP gateway
RTP/UDP
Voice packets
(point(point-point
connection)
Client Laptop
Application
Siemens
PBX
PSTN
transfer
SIP
SIP+App service
integration
13
SIP phone
PSTN phone
POTS phone