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QoS on Best-effort IP Networks

QoS on Best-effort IP Networks. Les Cottrell – SLAC www.slac.stanford.edu/grp/scs/net/talk/qos-itu-apr01/

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QoS on Best-effort IP Networks

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  1. QoS on Best-effort IP Networks Les Cottrell – SLAC www.slac.stanford.edu/grp/scs/net/talk/qos-itu-apr01/ Presented at the Joint SG13/SG16 Workshop Panel Session: "Achieving Multimedia QOS over IP-Based Networks"part of the ITU-T SG13/SG16 Workshop on IP Networking and Mediacom 2004, Geneva, Switzerland, April 25-27, 2001 Partially funded by DOE/MICS Field Work Proposal on Internet End-to-end Performance Monitoring (IEPM), also supported by IUPAP

  2. Overview • Measurement methodology • Delay • Loss • Jitter • Availability • Summary

  3. PingER PingER • Measurements from • 32 monitors in 14 countries • Over 600 remote hosts • Over 72 countries • Over 3300 monitor-remote site pairs • Measurements go back to Jan-95 • Reports on RTT, loss, reachability, jitter, reorders, duplicates … • Uses ubiquitous “ping” facility of TCP/IP • Countries monitored • Contain 78% of world population • 99% of online users of Internet

  4. RTT from ESnet to Groups of Sites RTT ~ distance/(0.6*c) + hops * router delay Router delay = queuing + clocking in & out + processing ITU G.114 300 ms RTT limit for voice 20%/year

  5. RTT Region to Region OK White 0-64ms Green 64-128ms Yellow 128-256ms NOT OK Pink 256-512ms Red > 512ms OK within regions, N. America OK with Europe, Japan

  6. RTT from California to world Europe E. Coast Brazil E. Coast US W. Coast US 300ms RTT (ms) Europe & S. America 3*0.6c Longitude (degrees) 300ms Frequency Source = Palo Alto CA, W. Coast RTT (ms.) Data from CAIDA Skitter project

  7. Loss seen from US to groups of Sites 50% improvement / year ETSI DTR/TIPHON-05001 V1.2.5 threshold for good speech

  8. Loss to world from US Using year 2000, fraction of world’s population/country from www.nua.ie/surveys/how_many_online/

  9. Losses between Regions

  10. “Jitter” from N. America to W. Europe “Jitter” = IQR(ipdv), where ipdv(i) =RTT(i) – RTT(i-1) 214 pairs ETSI: DTR/TIPHON-05001 V1.2.5 (1998-09) good speech < 75ms jitter

  11. “Jitter” between regions ETSI: DTR/TIPHON-05001 V1.2.5 (1998-09) 125ms=Med 225ms=Poor 75ms=Good Jitter varies with loading

  12. SLAC-CERNJitter ETSI/TIPHON delay jitter threshold (75 ms)

  13. Availability – Outage Probability Surveyor probes randomly 2/second Measure time (Outage length) consecutive probes don’t get through Heavy tailed outage lengths (packet loss not Poisson) http://www-iepm.slac.stanford.edu/monitoring/surveyor/outage.html

  14. More Information • This talk: • www.slac.stanford.edu/grp/scs/net/talk/qos-itu-apr01/ • IEPM/PingER home site • www-iepm.slac.stanford.edu/

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