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My Experiences, results and remarks to TCP BW and CT Measurements Tools

My Experiences, results and remarks to TCP BW and CT Measurements Tools. Jiří Navrátil SLAC. My interests concerns o n. How to achieve full BW utilization Analysis of Tools for BW estimation New methods of CT detection. Inspira tion Les Cottrell IEPM metrics

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My Experiences, results and remarks to TCP BW and CT Measurements Tools

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  1. My Experiences, results and remarks to TCP BW and CT Measurements Tools Jiří Navrátil SLAC

  2. My interests concerns on • How to achieve full BW utilization • Analysis ofTools for BW estimation • New methods of CT detection

  3. Inspiration • Les Cottrell IEPM metrics • Jin Gujun (LBNL) netest-2 recommendation • Feng Wu-Chun (LANL) simulations • Diana Katabi, Charles Blake (MIT) bottleneck detection

  4. Area of saturation = area of full utilization • TCP windows size (not sufficient for HSL) • Parallel streams • combination

  5. Saturation point

  6. Nobig difference between speed for P2,P4,P8, ..

  7. Inflexion point

  8. Why such distribution of throughput for individual streams ?

  9. Internet path Out In Virtual queue

  10. Problems of slow and high loaded lines • All parallel streams share same “virtual queue” • All “my traffic” share same queue with outside CTvisible in statistics for “streams speed”visible in time reports (In iperf)

  11. Why I cannot achieve more bandwidth with less streams? Is there a CT ? I don’t know !

  12. Conclusion: The other TCP applications behave very similarly in same environment But not all applications are so aggressive as Iperf !

  13. Used tools for BW estimations • Pathrate • Pathload • Iperf • Netest-2 • Incite BWe • UDPmon

  14. Short characteristic of methods Patharate + accurate - not very reliable, long run time Pathload + accurate, fast, light - limited range of operation ( < 155 Mbps)

  15. Small comparisons

  16. Short characteristic of methods Iperf + reliable - must be configured to use full BW and postprocessed - heavy load of lines during operation Netest-2 + reliable, good reports - must be configured to use full BW, - accurate (different timing scheme)

  17. INCITE: Edge-based Traffic Processing and Service Inference for High-Performance Networks Richard Baraniuk, Rice University; Les Cottrell, SLAC; Wu-chun Feng, LANL Incite BW estimator

  18. P2 P1 BWe ~f(VQ) =f(dTR) dTR <0,RTT> dTS (20 ms) Time P1 P2 P1 P2 dtp2 dTR RTT P1 P2 dtp1

  19. freq= volume/dt volume ~ pkt_length*8 dt ~ F(VQ) ~ F(Internet) BWe=Mean(freq) Open Problem What is pkt_length?

  20. All “my test traffic” share same queue with outside CT • (It means that delay caused to my pkts by VQ • is not dependent only on my pkt_lengths !) • The accuracy is dependent on knowlegde of • packet distribution on particular path. • The average packet length ~1000 bytes • gives reasonable results. Virtual queue

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