Voice over IP Implementation

Voice over IP Implementation
Ruchi Prasad
Director, Global CDMA Product Marketing
November, 2004
VoIP Objectives
Packetizing
Traditional Voice
Native VoIP On
The Device
Cost Savings
Application
Integration
Application Integration Will Drive
VoIP Implementation
nortelnetworks.com
Transport Convergence
Optimized, Packetized Voice Transport
•
•
Call Servers – P-MSC, CS 2K
Media Gateway
Internet
PSTN
BBSN
MPE
PDSN
HA
WLAN
HA
WLAN
IP
IP
PDG
PDG
Reducing the total cost of ownership
• Transport and transcoding optimization
• Reduced footprint and power
• Reduced number of switching centers
nortelnetworks.com
Services Convergence
Enhanced Access
1xEV-DO Rel A
Efficient support of real -time Apps
Optimized
Standardized services framework
Opportunity for service integration
Internet
PSTN
BBSN
MPE
PDSN
HA
WLAN
HA
WLAN
IP
IP
PDG
PDG
Delivering revenue generating services
•
•
•
Mass Market Real -time Apps like VoIP and Multimedia
Broadcast/Multicast Apps
Interworking between different Access Technology and Wireline
nortelnetworks.com
End to End Standards Perspective
Go & Gq interfaces
MMD (Q1 ‘05)
• Support for Service Based Bearer Control
• Delivers common SIP services framework
IP
HSS
SS7
GW
App
Servers
AAA
RADIUS
PDF
CSCF
IM
Subsystem
PS Domain
Compact
Metrocell
eBSC/RNC
TIA856-A (published)
TIA1054 (Q4’04)
• Throughput & packing efficiency
improvements
• ACK based
retransmission
• Support multi-flow operation for
QoS
• Packet based framing
• Provide support for
QoS and multiple
service instances
• Support for inter-RNC
handoff
TIA835-D (Q1 ’05)
• QoS support
BGCF
MGW
PDSN
MGCF
• Improved slotted mode
operation
Internet
Intranet
PSTN
TIA878-A (Q4’04)
• QoS support
(QoS_BLOB flow
mapping)
nortelnetworks.com
IETF (published)
• Defined QoS
specifications
outside managed
network
VoIP Implementation Challenges
QoS Procedures to
agree between
Access and Core?
VoIP Capacity?
SIP Messaging
Call Set up
delay impact?
Transport
Network
IMS
Client
BTS
SIP
HA
Radio Resource Allocation
CSCF
Media
Application based Prioritization
External Networks:
HO
Traffic
Marking?
IMS
Client
Mobility Mgt
Impact on Real
Time App?
Traffic Priority
Transcoding
and Voice quality
Wireless
BTS
PSTN
Controlling End to End Delay, Voice Quality, &
Capacity To Provide Anortelnetworks.com
Consistent User Experience
Other VoIP Implementation Challenges
• Client / Devices
– Clients and Apps for Wireless and Wireline Devices (Video, PTT, VOIP)
– Dual mode devices to overcome coverage limitations
• 1X Interworking requirements
– MSC/IS-41 feature reuse
– 1X interworking for voice / data, requirements
• System Integration and Inter-op
– 3rd Party apps, clients, open interfaces (Interoperability and Performance
Management is critical
• Security Management
– Firewall Traversals, Denial of Service attacks, Virus Protection, VPN
Management
• Regulatory Issues
– CALEA, E911, inter/intra-LATA, etc…
nortelnetworks.com
VoIP Capacity / Quality Tradeoff
System
Capacity
1xEV-DO
For CSD QOS
Can we match 1X
capacity?
1X
QOS
Delay & Jitter
Best Effort
Service Quality
eg. HTML &
Video Streaming
How far are
you willing to
back up on the
quality curve
for your voice?
nortelnetworks.com
Circuit Switched
Service Quality
eg. VoIP
VoIP End-End Delay & Optimization
Chosen by
source terminal
or ingress GW
Dependent on QoS provided by
traversed networks (each network
component has its specific contribution)
Packetization
delay
Total
m inim al
delay
Total
queuing
delay
Chosen by the
destination terminal or
egress GW
D e jittering
delay
M 2 E d e lay
Echo
control
Dejittering
delay
Packet
size
Codec
Header
compression
Balancing Voice Quality &
capacity
Network parameters
•Minimal delay
•Delay Jitter
•Packet loss
Voice quality
Capacity
Access parameters
Dominated by FL, RL scheduling,
physical layer characteristics and
blocking model
nortelnetworks.com
VoIP Quality In An End-to -End Network
Voice quality is influenced by the various nodes involved in an end to end call
Improve Echo Return Loss
Handheld AT
Quality
codecs
Air link loading - delay
SIP compression
AT Modem
BTS
A
HA
Handoff Performance
Jitter Buffer Optimization - Reduce nodal delay
Prioritize traffic (Diffserv, MPLS…)
PC
A
RNC
Land Phones
IMS
MGW
PSTN
LAN Phones
ISP Mdm
BB Mdm
- or -
IP Phone
Wireless Network
IMS
MGW
Remove latency Implement TrFO
PSTN
(Circuit MSC)
Packetized
Circuit Core
MSC
MG
nortelnetworks.com
BSC
BTS
Implementing Mobile VoIP
PDSN 1
PDSN 2
RNC A
RNC C
Inter-RNC
Inter-RNC soft
Handoff
Pre-standard
RNC B
RNC D
1X
Intra-RNC
1xEV-DO Rel A
Data Source
Channel
Defined –
Quantification
upon
implementation
in field
1xEV-DO-Rel A
1xEV-DO-Rel A
Inter-Technology Handoff
1xEV-DO to 1X (CS)
Not defined – Lose voice session
when you move out of DO Coverage
Inter-PDSN
IS-835B Inter-PDSN
Fast Handoff
Defined
nortelnetworks.com
What is Quality of Experience?
QoE is the end user’s
perception of service
performance
– QoE reflects the user’s experience
• efficiency of task completion:
what does the user want to do?
• ease of use: is it easy to see how
it works and what is happening?
• transparency of technology: does
the technology facilitate the task or
does it get in the way?
– QoE is quantified using behavioral
science methods i.e., subjective
testing
– Performance limits based on QoE are
used to ensure that the service
delivers acceptable performance
North American users
expectations…
– Expect dial tone immediately
– Expect the call to go through right away
– Expect to keep the line as long as they
want it
– Expect to be able to hear and converse on
the call almost as easily as they do in
person
– Wireless Users are willing to accept a
slightly lower voice quality as a tradeoff for
the benefit of unlimited mobility
– Wireless Users are accustomed to having
different voice quality calls dependant on
destination. (i.e. Land terminated = good,
Mobile Terminated= lower quality due to
end user location or environment)
Voice QoE = f( delay, distortion,
loss plan , echo control)
nortelnetworks.com
Nortel Networks
Delivers End to End QoE For VoIP
QoE Indicators
• No service available
• Service rejected
• Call setup time
Network Metrics
•
•
•
•
•
•
•
RF Coverage
Blocking rate
Drop rate
Delay
Throughput
Jitter
BLER
• Response time
• Stream blocking/freezing
• Visual noise
• Audio quality
•…
Roaming
Partners
HLR
MSC
MSC
SIG
PSTN
GRX
IWF
Wireless
Gateway
WG AN
BG
BG
ATM or IP
Packet Core
Wireless
Wireless
Gateway
Gateway
WG AN
PP8600
PP8600
GGSN
GGSN
RNC
RNC
RNC
BSC
PP8600
PP8600
PP8600
PP8600
Intranets
Alteon
LoadBalancing
Firewall
BGP
-4 Router
Network Management Center
BGP - 4 Router
BGP -4 Router
Data Center
Internet
Network
End-User Perception
Optimizing infrastructure and application/clients to
deliver satisfactory QoE in a cost efficient manner
nortelnetworks.com