What’s Good What’s Wished For

1. What’s GoodWhat’s Wished For Peter O’Neil Poneil@ucar.edu August 2, 2002

2. What’s Good • tracking loss, RTT, throughput, modifying streams and window size • clearing up guesswork by adding specific information • clarifies bottlenecks and performance problems • tcp oscilliscope to guide tuning problems one by one as veils removed • shows small receiver sockets, % packet loss, and degree of difficulty with throughput • tune hosts to support SACK, pMTUd, timestamps, and window scaling, send and receive window buffers • test and prove OS stacks behaving properly given parameters set • effective diagnostic tool, tuning guide, and good for closing wizard gap • teaching tool for displaying network behavior and BW*Delay effects • diagnostic tool for network signatures for "typical“ network problems and suggests changes/fixes to improve performance • provides results from experimenting with various tuning options and comparing results (experimental transport tool framework for testing actual behavior on networks rather than just testing on simulators) • dx firewall effects, out-of-order packets, path capacity,caching, queuing, BW*D, buffer limits, wscale clamps,loss intensity, bottlenecks, recovery, timeouts,

3. Wish List • netBSD port • OS vendor involvement particularly AIX and Solaris • iperf mods to use web100 to identify when slow start finished and report throughput • dynamically select CID • highlight interesting results from mib variables and produce text summary/recommendations • streams and window prediction • point out where in the network problem lies • receiver side stats • analyze what from WAD can/should go into kernel • web100 trace file capability • variable for count of duplicate data segments at receiver • remove wscale restriction

4. Thank You!