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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
Purpose of Presentation
• 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
TR30.3 Modem Test Standards
• 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
– Error rate measured against single impairments such as Gaussian noise
– Severe stress conditions
• Network Model Coverage (NMC)
– 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
– 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
Converged Network Reference Model Diagram
TIA-793 Network Model
TEA D L LTelco
Switch Gateway
TIA-793 Network Model
TEA DTelco
Switch GatewayIP Network
R,G,S*
R,G,S* R,G,S* GatewayGateway L L
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
Test Voice, Fax or Data over IP using Converged Network Model
Voice, Video, Data, Fax, etc.
Analog PSTN
Simulator 1
IPSimulator
Gateway Gateway
Analog PSTNSimulator 2
Voice, Video, Data, Fax, etc.
Example of Test Profile with Fixed Values of Network Impairments
Impairment Type Units Range
Jitter ms +/- 75
One Way Latency ms 50 to 150
Sequential Packet Loss #sequential packets losses 0 to 3
Rate of Sequential Loss sec-1 < 10-3*
Random Packet Loss % 0 to 2
Out of Sequence Packets % 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
• Link Failure
• Load Sharing
• Time Drift
• MTU Size
• Background Traffic
• One Way Delay
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 Based on QoS ClassesTest Profiles QoS Class
(Y.1541)Applications (Examples) Node Mechanisms Network Techniques
A(VoIP, MoIP, FoIP, ToIP)
0 Real-Time, loss sensitive, Jitter sensitive, high interaction (VoIP, VTC) Strict QoS. Guaranteed no over
subscription on links.
Constrained Routing and Distance
B(VoIP, MoIP, FoIP, ToIP)
1 Real-Time, Jitter sensitive, interactive (VoIP, VTC). Separate Queue with preferential
servicing, Traffic grooming
Less constrained Routing and Distances
C(FoIP only)
2 Transaction Data, Highly Interactive (Signaling)
Separate Queue, Drop priority
Constrained Routing and Distance
3 Transaction Data, Interactive Less constrained Routing and Distances
4 Low Loss Only (Short Transactions, Bulk Data, Video Streaming)
Long Queue, Drop priority Any route/path
5 Traditional Applications of Default IP Networks
Separate Queue (lowest priority) 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
0
0 10 20 30 40 50 60 70 80 90 100
Percentage of Network Coverage
Device ADevice BDevice C
Qo
S,
PE
SQ
, P
SQ
M,
MO
S,
Th
rou
gh
pu
t, C
on
ne
ct R
ate
, e
tc.
Value of Converged Network Model
• 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
• Design Engineers
• Test houses
• Magazines and product reviewers