Analyze Assure Accelerate
Network Model for Evaluating Multimedia
Transmission Performance Over Internet Protocol
PN-3-0062
Will become TIA/EIA-921
Jack Douglass, Spirent
Chair TIA TR30.3
November 10, 2003, TIA TR41
TR30.3 30312022
TR41.4-03-11-060-L jack.douglass@spirentcom.com

•
Establish a formal liaison between TR30.3 and TR41 to help develop Network Model for Evaluating Multimedia Transmission
Performance Over Internet Protocol (PN-3-0062)
•
Other Liaisons Activities
–
ITU-T SG15 Questions 5, 6, 7
–
ITU-T SG16 Question
–
IETF
–
Etc.
•
Invite TR41 members to TR30.3 meetings to work on IP Network
Model
–
IP Network Statistics
–
Network Architecture
–
Test Scenarios

•
TIA/EIA 496A-1989: Interface Between Data Circuit Terminating
Equipment (DCE) and the Public Switched Telephone Network
–
Included Network Model for Evaluating Modem Performance
•
TIA/EIA TSB 37A-1994: Telephone Network Transmission Model for Evaluating Analog Modem Performance, which became ITU-T
Recommendation V.56bis-1995
•
EIA/TIA TSB 38-1994: Test Procedures for Evaluation of 2-Wire 4
Kilohertz Voice Band Duplex Modems, which became ITU-T
Recommendation V.56ter-1996
•
ANSI/TIA/EIA 3700-1999: Telephone Network Transmission
Model for Evaluating Analog Modem Performance
•
ANSI/TIA/EIA 793 -2000: North American Telephone Network
Transmission Model for Evaluating Analog Client and Digitally
Connected Server Modems
•
ANSI/TIA 876 – 2002: North American Network Access
Transmission Model for Evaluating xDSL Modem Performance

Network Model Coverage (NMC) Methodology
•
Waterfall Curves
–
Traditional method of measuring modem performance
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Error rate measured against single impairments such as Gaussian noise
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Severe stress conditions
•
Network Model Coverage (NMC)
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Introduced by TR30.3 in TIA/EIA-1992 TSB37
–
Network Model is a portrait of the real network
–
Statistically based Network Model -- Likelihood of Occurrence (LOO) of a given connection
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Modem performance evaluated using a Impairment Combinations and Local
Loop Combinations
–
Curve showing Percentage of Network Model Vs Throughput
•
Estimates percentage of network of the real network over which the modem can be expected to operate
–
Compare performance of different models or manufactures of modems
–
Network Model is independent of modem technology

Network Model for Evaluating Multimedia
Transmission Performance -- PN-3-0062

Converged Network Reference Model Diagram
TE
A
Telco
Switch
D
Gateway
TIA-793 Network Model
L
IP Network
L
TE
A
Telco
Switch
D
Gateway
TIA-793 Network Model
Gateway
L
R,G,S*
R,G,S*
R,G,S*
L
Gateway

Test Scenario:
PSTN to PSTN connections through a managed IP network

Examples of Communication Equipment that can be tested over the Converged Network
Model
•
IP Network Devices such as User Agents, Call Agents,
Media Servers, Media Gateway Controllers,
Gatekeepers, Application Servers, Edge Routers,
Gateways
•
Plain Old Telephone Service (POTS) and IP telephones
•
Voice-over-IP (VoIP) gateways
•
ITU-T V-series data modems, both analog client and digitally connected server
•
T.30 and T.38 facsimile devices and gateways
•
V.150.1 and voiceband data (VBD) modem-over-IP gateways
•
TIA-1001 (and V.toip) textphone-over-IP gateways

Voice, Video,
Data, Fax, etc.
Analog PSTN
Simulator 1
Gateway
IP
Simulator
Gateway
Analog PSTN
Simulator 2
Voice, Video,
Data, Fax, etc.

IP Network
Devices
IP
Simulator
IP Network
Devices

Impairment Type Units Range
Jitter
One Way Latency
Sequential Packet Loss
Rate of Sequential Loss
Random Packet Loss
Out of Sequence Packets
%
% ms ms
#sequential packets losses sec -1
+/- 75
50 to 150
0 to 3
< 10 -3*
0 to 2
0 to 10 -1**
•
Network Impairments Conditions could be based on set of impairment combination that have fixed values
–
Stress IP Network Device
•
Impairments on a real IP Network are not fixed

Parameters that Need to be Considered when Simulating an IP Network
•
Network Architecture
•
Types of Access Links
•
QoS controlled Edge Routing
•
Route Flapping
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Link Failure
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Load Sharing
•
Time Drift
•
MTU Size
•
Background Traffic
•
One Way Delay

Time

Time Varying Statistically Based IP
Network Impairment Condition (IC)
IC1
LOO X%
IC2
LOO X%
IC100
LOO X%
•
Each Impairment Condition is assigned a Likely-hood of
Occurrence (LOO) based on real IP Network Statistics, Network
Architecture, Classes of Service
•
The goal is to have approximately 100 test combinations so that an automated run of the test suite completes in less than a day.

Test Profiles
A
(VoIP, MoIP,
FoIP, ToIP)
B
(VoIP, MoIP,
FoIP, ToIP)
C
(FoIP only)
4
5
2
3
QoS Class
(Y.1541)
0
1
Applications (Examples) Node Mechanisms
Real-Time, loss sensitive, Jitter sensitive, high interaction (VoIP, VTC)
Strict QoS. Guaranteed no over subscription on links.
Real-Time, Jitter sensitive, interactive
(VoIP, VTC).
Separate Queue with preferential servicing, Traffic grooming
Transaction Data, Highly Interactive
(Signaling)
Transaction Data, Interactive
Separate Queue, Drop priority
Low Loss Only (Short Transactions,
Bulk Data, Video Streaming)
Traditional Applications of Default IP
Networks
Long Queue, Drop priority
Separate Queue (lowest priority)
Network Techniques
Constrained Routing and Distance
Less constrained Routing and
Distances
Constrained Routing and Distance
Less constrained Routing and
Distances
Any route/path
Any route/path
•
Statistically based models can be created for different
QoS Classes

Example of Network Model Coverage
(NMC) Curve
Parameter X Vs Network Model Coverage Percentage
Device A
Device B
Device C
0
0 10 20 30 40 50 60 70
Percentage of Network Coverage
80 90 100

•
Predicts product performance under statistically base network conditions
•
Finds design weaknesses
•
Find compatibility issues between network equipment
•
Facilitates isolating and resolving field problems
•
Assists in evaluating different technologies

Target Audience for Converged Network
Model
•
Operating Companies
•
Service Providers
•
Manufacturers
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Design Engineers
•
Test houses
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Magazines and product reviewers

•
Comments, Suggestions and Recommendations
•
Input for Network Model
–
IP Network Statistics
–
Network Architecture
–
Test Scenarios
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Invited to participate in TR30.3