Performance Working Group at Joint Techs at Fairbanks, Alaska

12-July-2011

Welcome  -- _Carla Hunt

Internet2 Update -- Aaron Brown and Jeff Boote

Fiber Asset Management Software -- Carla Hunt, MCNC

ESnet Distributed Help Desk -- Brian Tierney or Phil DeMar, ESnet

Periscope Presentation  -- Martin Swany, University of Delaware

No questions

IPv6, backbone measurements, and Netflow -- Matt Zekauskas, Internet2

Brian Tierney asked if the backbone bwctl and owamp measurement traffic was using IPv6. Matt said that it was, but that the meaurements being shown was connector traffic, and not backbone traffic.

Issues around Buffer Bloat - Jim Warner, UC Santa Cruz

Jim Warner noted that Jim Getty has been promoting the "buffer bloat" issue. Jim Warner felt that the mailing lists and websites like fasterdata.es.net were telling people that bigger buffers aren't a problem. Carla Hunt asked what the recommendation that the mailing lists and websites are suggesting? Jim said that fasterdata.es.net recommended an outbound queue length of 1000 packets for 1G, and 10000 packets for 10G. He felt that was far too much buffer at home. Most of the buffers filling up are in the DSL boxes which are unchangeable. He noted that the outbound traffic can be shaped so that DSL queueing doesn't happen. Martin Swany felt that this was a TCP problem. He felt it was misguided to screw with sending so that TCP doesn't get confused. Jon said that TCP worked that way, and because of that, we can't ignore it. Jon thought the problem with buffering was that it was dependent on the link speed the router was attached to. One megabyte of buffering was nothing for 1G ethernet, but on DSL, it's forever. Jim noted that the effect of all this "hidden buffering" was a large percentage of a second (1/3 and higher). Prasad noted that it can be even worse on a noisy channels like wireless where retransmits happen after 60ms so you can get even higher blocking times. Jim said that wireless was a problem for lots of reasons, including that valid wireless speeds varied from 2Mbps to 100Mbps.

AGENDA AND ABSTRACTS

Fiber Asset Management Software -- Carla Hunt, MCNC

ESnet Distributed Help Desk -- Brian Tierney or Phil DeMar, ESnet

Periscope Presentation  -- Martin Swany, University of Delaware

IPv6, backbone measurements, and Netflow -- Matt Zekauskas, Internet2

Issues around Buffer Bloat - Jim Warner, UC Santa Cruz