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TCP behavior on Trans-Atlantic lambda’s

Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003. EU - IST DataTag project, WP3. TCP behavior on Trans-Atlantic lambda’s. Wim Sjouw , Antony Antony, Hans Blom, Cees de Laat, Jason Lee.

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TCP behavior on Trans-Atlantic lambda’s

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  1. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  2. EU - IST DataTag project, WP3 TCP behavior on Trans-Atlantic lambda’s Wim Sjouw, Antony Antony, Hans Blom, Cees de Laat, Jason Lee Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  3. LFNT Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  4. Advanced Internet Research Wim SjouwSantiago de Compostela 14 February 2003

  5. Long: RTT > 50 msec Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  6. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  7. FAT B > 622 Mbps Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  8. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  9. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  10. Surprise Surprise TCP throughput 90 Mbps Surprise Surprise Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  11. UDPmon Probe the network with trains of UDP packets Packets are: numbered & time stamped Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  12. UDPmon Probe the network with trains of UDP packets • variable number of packets • varable packet length • variable inter packet delay Packets are: numbered & time stamped Very precise timing with Pentium proc. clock Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  13. UDPmon Probe the network with trains of UDP packets • number of packets: 5000 • packet length: 1000 Bytes • inter packet delay: 0 μsec Timing: 10 ns Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  14. UDPmon Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  15. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  16. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  17. Nb = 1500 Nd = 0 l = 1000 f = 1 Gbps s = 622 Mbps then M = 0.5 MB Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  18. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  19. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  20. R = 100 ms Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  21. Back to TCP • TCP is bursty due to: • sliding window protocol • slow start algorithm Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  22. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  23. W= sent segments Y= advertised window G= ACK’s R= retransmits P= SACK’s Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  24. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  25. 512 packets in 4 ms Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  26. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  27. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  28. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  29. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  30. So overall pick from thismenu: • flow control • traffic shaping • RED (Random Early Discard) Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  31. Receiver: • buffer capacity of NIC • interupt latency & coalescence • interupt overhead • PCI bus width and PCI bus speed • TCP stack overhead & complexity • OS overhead Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  32. <Mac OS < Linux Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  33. Conclusions: • ‘old’ TCP does not perform in a “Long Fat Network” • UDP does perform, but unacceptable • End system(s) dictate overall performance: • O.S • Memory • NIC Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  34. beware of Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  35. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  36. Thanks! http://www.science.uva.nl/research/air/ Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  37. Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

  38. UDPmon: www.hep.man.ac.uk/~rich/net Richard Hughes Johnes Advanced Internet Research Wim Sjouw Santiago de Compostela 14 February 2003

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