TIA-921 (PN ) and ITU-T G.NIMM Network Model for Evaluating Multimedia Transmission Performance Over Internet Protocol Jack Douglass, Spirent Chair TIA TR30.3 August 2005 TIA TR

TIA-921 (PN ) and ITU-T G.NIMM Jitter, Latency, Burst Loss, Gap Loss Packet Loss, Out-of-Order Packets Route Flapping, Link Failure Scenario Based Time Varying IP Network Impairments IP Network Impairment Emulator Based on TIA-921 and ITU-T G.NIMM Types of DUTs IP Phones POTS over IP Media Gateways MGC User Agents Call Agents Media Servers Video Gatekeepers Application Servers Edge Routers Gateways Modems Fax

TIA-921 (PN ) and ITU-T G.NIMM Network Model for Evaluating Multimedia Transmission Performance TIA-921 / ITU-T G.NIMM

Network Impairments and Parameters that Affect Voice and Video Quality Network Architecture Types of Access Links QoS controlled Edge Routing MTU Size Packet Loss (Frame Loss) Out of order packets One Way Delay (Latency) Variable Delays (Jitter) Background Traffic (Occupancy) Timing Drift Route Flapping Signaling protocol mismatches Network faults Link Failures Voice Only Impairments – Echo – Voice coding algorithms – A/D and D/A Conversion – Noise – Circuit and External Video Only Impairments – Video coding algorithms – Variable and Fixed Frame Rates – Video Complexity

TIA-921and ITU-T G.NIMM IP Network Model

Typically test are run in one direction Tests may be run in both directions Impairments occur in both directions

TIA-921 and ITU-T G.NIMM Test Profiles Based on QoS Classes Statistically based models for different QoS Classes Service Test Profiles QoS Class (Y.1541) Applications (Examples)Node Mechanisms Network Techniques Well ‑ Managed IP Network (Profile A) 0High quality video and VoIP, VTC (Real-time applications, loss sensitive, jitter sensitive, high interaction) Strict QoS, guaranteed no over subscription on links Constrained routing and distance Best-Effort IP Network (Profile B) 1VoIP, VTC (Real-time applications, jitter sensitive, interactive) Separate queue with preferential servicing, traffic grooming Less constrained routing and distances Unmanaged IP Network, Internet (Profile C) 2Lower quality video and VoIP, signaling, transaction data (highly interactive) Separate queue, drop priority Constrained routing and distance 3Transaction data, interactive Less constrained routing and distances 4Short transactions, bulk data (low loss) Long queue, drop priority Any route/path 5Traditional Internet applications (default IP networks) Separate queue (lowest priority) Any route/path

TIA-921 and ITU-T G.NIMM Test Profiles Based on QoS (Y.1541) Classes Profile C Un-Managed Network Impairment Ranges Table 4 Profile B Best Effort Managed Network Impairment Ranges Table 3 Profile A Well Managed Network Impairment Ranges Table 2 Different test profiles for different Service Level Agreements (SLAs) Impairment TypeUnitsRange Jitter ms 0 to +/- 250 One Way Average Latency ms 50 to 800 Sequential Packet Loss # of sequential packets 2 to 500 Rate of Sequential Loss sec -1 < Random Packet Loss % 0 to 20 Out of Sequence Packets % 0 to 20 Impairment TypeUnitsRange Jitter ms 0 to +/- 75 One Way Average Latency ms 50 to 200 Sequential Packet Loss # of sequential packets 2 to 5 Rate of Sequential Loss sec -1 < Random Packet Loss % 0 to 2 Out of Sequence Packets % 0 to 0.1 Impairment TypeUnitsRange Jitter ms 0 to +/- 50 One Way Average Latency ms 20 to 60 Sequential Packet Loss # of sequential packets Random loss only Rate of Sequential Loss sec -1 Random Packet Loss % 0 to 0.05 Out of Sequence Packets % 0 to 0.001

TIA-921 and ITU-T G.NIMM 8 Impairment Severity Combinations Table 10: Impairment Severity Combinations Severity=>ABCDEFGH ImpairmentUnits Profile A LOO% Profile B LOO% Profile C LOO% Source Location (A) Parameters LAN A Occupancy% Access A Occupancy% MTU Abytes Core Network Impairments Route flap intervalseconds Route flap D delayms Delayms Jitterms Link fail intervalseconds Link fail durationms Packet loss% Destination Location (B) Parameters Access B Occupancy% MTU Bbytes LAN B Occupancy%

TIA-921 and ITU-T G.NIMM LAN and Access Rates Table 7: Access Rates for Home Locations Table 8: Access Rates for Business Locations Table 6: LAN Rates for Business Locations Table 5: LAN Rates for Home Locations 133 LAN/Access Rate Combinations Home Rates Business Rates LAN RateLOORepresents Mbit/s% b, 10BaseT hub g, 100BaseT hub LAN RateLOORepresents Mbit/s% b, 10BaseT g, 100BaseT hub BaseT switched, Gbit Ethernet Access RateLOORepresents Toward coreFrom core% kbit/s Cable, ADSL Cable, ADSL Cable, ADSL Access RateLOORepresents Toward coreFrom core% kbit/s ADSL entry ADSL premium T T3 LAN and Access Rates (New Revision of Standard/Recomendation) will change as network conditions change

Testing with Fixed Levels of IP Impairments IP Impairment network emulators exist today that provide fixed or semi-fixed levels of IP impairments. Real IP Network Impairments Vary Over Time significantly over time and are bursty in nature Fixed Jitter & Packet Loss Fixed Packet Jitter

TIA-921 and ITU-T G.NIMM Statistically Based IP Network Impairment Conditions (ICs) based on SLAs IC– 96A Probability (LOO = % ) Call Quality Metric Impairment Condition

TIA-921 and ITU-T G.NIMM Statistically Based IP Network Impairment Conditions (ICs) based on SLAs Call Quality Metric Impairment Condition IC– 96E Probability (LOO = % )

TIA-921 and ITU-T G.NIMM Statistically Based IP Network Impairment Conditions (ICs) based on SLAs Link Failure Route Flap Call Quality Metric Impairment Condition IC– 96H Probability (LOO = %)

TIA-921 and ITU-T G.NIMM Statistically Based IP Network Impairment Conditions (ICs) based on SLAs Each Impairment Condition has a Likely-hood of Occurrence (LOO) – Based on real IP Network Statistics – Based on Network Architecture – Based on Classes of Service Definitive set of test conditions – 1064 Impairment Combinations – Tests may be automatically – Typically 2 min per Impairment Condition Approximately 1.5 days to run complete set of tests – Impairment Condition may be correlated with appropriate quality measurement Voice Quality Metric (MOS, PESQ, PSQM, R-Factor) Video Quality Metric

TIA-921 and ITU-T G.NIMM Example of Network Model Coverage (NMC) Curve Test Results from 1064 Statistically based IP Network Impairment Combinations

TIA-921 and ITU-T G.NIMM Example of Network Model Coverage (NMC) Curve Test Results from 1064 Statistically based IP Network Impairment Combinations

History of TR30.3 Network Model 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 : Test Procedures for Evaluation of 2-Wire 4 Kilohertz Voice Band Duplex Modems, which became ITU-T Recommendation V.56ter-1996 ANSI/TIA/EIA : Telephone Network Transmission Model for Evaluating Analog Modem Performance ANSI/TIA/EIA : 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

TR30.3 Liaison Activities Liaisons activities between TR30.3 and appropriate committees to develop TIA-921 (PN ), Network Model for Evaluating Multimedia Transmission Performance Over Internet Protocol – TR41.4 – TR45.5 – ITU-T SG12 – ITU-T SG9 – ITU-T SG15 Working with Operating Companies and Service providers to provide statistically accurate IP network impairment model

TIA-921 Target Audience for Network Model Network Equipment Manufacturers Operating Companies Service Providers Design Engineers Test houses Magazines and product reviewers