1. Telecommunications Industry AssociationTR-30.3/06-05-011

2. ITU-T G.1050/TIA-921 IP Network Model Overview March 2006 Jack Douglass jack.douglass@spirentcom.com & Ross Cassan ross.cassan@spirentcom.comjack.douglass@spirentcom.comross.cassan@spirentcom.com Spirent Communications

3. G.1050/TIA-921 Overview Sources of network impairments Network models including expected values for – Latency – Jitter – Packet loss – Out of sequence packets – Delay

4. Network Impairments and Parameters that Affect 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, Congestion, Network Load) Route Flapping Signaling protocol mismatches Network faults Link Failures

5. ITU-T G.1050 and TIA-921 IP Network Model 1000BaseX 100BaseT Switch 100BaseT Hub 10BaseT WLAN (~4Mbps) ----------------- Occupancy level Packet loss 64kbps 128kbps 256kbps 384kbps 512kbps 768kbps T1/E1 T3/E3 ADSL Cable Fiber ---------------- Occupancy level Qos Edge Router LAN A Core IP Network DUT A Route flapping Link Failures One-way delay Jitter Packet loss Packet Reorder Local Access A DUT B LAN B Local Access B 64kbps 128kbps 256kbps 384kbps 512kbps 768kbps T1/E1 T3/E3 ADSL Cable Fiber ---------------- Occupancy level Qos Edge Router 1000BaseX 100BaseT Switch 100BaseT Hub 10BaseT WLAN (~4Mbps) ----------------- Occupancy level Packet loss

6. ITU-T G.1050 and TIA-921 Test Profiles ITU-T Recommendation Y.1541 uses a similar approach, but there is not a one-to-one mapping. Service Test Profiles Applications (Examples)Node MechanismsNetwork Techniques Well ‑ Managed IP Network (Profile A) High 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 Partially- Managed IP Network (Profile B) VoIP, 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) Lower quality video and VoIP, signaling, transaction data (highly interactive) Separate queue, drop priority Constrained routing and distance Transaction data, interactive Less constrained routing and distances Short transactions, bulk data (low loss) Long queue, drop priority Any route/path Traditional Internet applications (default IP networks) Separate queue (lowest priority) Any route/path

7. ITU-T G.1050 and TIA-921 Test Profiles based on ITU-T Y1541 Different test profiles for different Service Level Agreements (SLAs) Profile A – Well-Managed Network Impairment Ranges Y.1541 QoS Level – suitable for high quality video and VoIP Most Service Providers will be supporting this SLA for IPTV

8. ITU-T G.1050 and TIA-921 Test Profiles based on ITU-T Y1541 Different test profiles for different Service Level Agreements (SLAs) Impairment TypeUnitsRange (min to max) One Way Latencyms50 to 200 (regional) 50 to 400 (intercontinental) Jitter (peak to peak)ms0 to 150 Sequential Packet Lossms40 to 200 Rate of Sequential Losssec -1 < 10 -3 Random Packet Loss%0 to 2 Reordered Packets%0 to 0.01 Profile B – Partially-Managed Network Impairment Ranges Y.1541 QoS Level – suitable for Lower quality video and VoIP

9. ITU-T G.1050 and TIA-921 Test Profiles based on ITU-T Y1541 Different test profiles for different Service Level Agreements (SLAs) Impairment TypeUnitsRange (min to max) One Way Latencyms50 to 800 Jitter (peak to peak)ms0 to 500 Sequential Packet Lossms40 to 10,000 Rate of Sequential Losssec -1 < 10 -1 Random Packet Loss%0 to 20 Reordered Packets%0 to 0.1 Profile C – Un-Managed Network Impairment Ranges Y.1541 QoS Level – Internet little or no guarantees

10. ITU-T G.1050 and TIA-921 8 Impairment Severity Combinations Table 10: Impairment Severity Combinations Severity=>ABCDEFGH* ImpairmentUnits Profie A LOO%50301550000 Profile B LOO%525302510500 Profile C LOO%5510152025155 Source Location (A) Parameters LAN A Occupancy%12358121620 Access A Occupancy%01248153050 MTU Abytes512 1508 Core Network Impairments Route flap intervalseconds03600180090048024012060 Route flap delayms0248163264128 Delayms48163264128256512 Jitter (peak to peak)ms510244070100150500 Link fail intervalseconds03600180090048024012060 Link fail durationms06412825640080016003000 Packet loss%00.010.020.040.10.20.51 Reordered packets%00.000250.00050.0010.0050.010.050.1 Destination Location (B) Parameters Access B Occupancy%01248153050 MTU Bbytes512 1508 LAN B Occupancy%12358121620

11. ITU-T G.1050 and TIA-921 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% 475802.11b, 10BaseT hub 2025802.11g, 100BaseT hub LAN RateLOORepresents Mbit/s% 420802.11b, 10BaseT 20 802.11g, 100BaseT hub 10060100 BaseT switched, Gbit Ethernet Access RateLOORepresents Toward coreFrom core% kbit/s 12876840Cable, ADSL 384153650Cable, ADSL 384300010Cable, ADSL Access RateLOORepresents Toward coreFrom core% kbit/s 384153640ADSL entry 384300015ADSL premium 1536 40T1 43000 5T3 LAN and Access Rates (New Revision of Standard/Recomendation) will change as network conditions change

12. Impairment Characteristics Good Bad Severe 1064 Impairment Combinatoins Link Failure Route Flap

13. ITU-T G.1050 and TIA-921 Example of Network Model Coverage (NMC) Curve OR Video Quality may also be plotted

14. ITU-T G.1050 and TIA-921 Example of Network Model Coverage (NMC) Curve OR Video Quality may also be plotted