Hi David, Respones to some of your questions inline:
> 1) What's a good initial value for the cwnd, whether starting from scratch or after a RTO? I know RFC2581 says one thing, and 3465 says another, and others say other things. I'm curious what you actually use and like, and why. Linux has a value of 2. According to RFC 2414, you can set it to 4 x MSS. For media applications, it is better to set it to this value. MSS=maxium segment size and is typically 536 or 1460 bytes (the number might be off by some bytes but they are in this range) > 2) To what do you set the ssthresh in response to a RTO? To a fixed-fraction of pipe (say, 50%) or some fraction of something else? ssthresh is set to half of the number of packets in flight. See this paper on how Linux does it. http://www.cs.helsinki.fi/research/iwtcp/papers/linuxtcp.pdf > 3) How far do you "fall back" the cwnd in response to a RTO? To a fixed value (say, 1472 bytes) or to some fraction of something else? one MSS. > 5) How far do you "fall back" the cwnd in response to a RTO? To 'ssthresh' or something else? cwnd is set to one MSS inresponse to a timeout. It is set to half of the number of packets in flight after a TDACK loss (or ssthresh which was updated at the time of the TDACK loss). Regards, salman On Sat, 21 Oct 2006, Wes Felter wrote: > On Oct 20, 2006, at 6:22 PM, David Barrett wrote: > > > Following up on my earlier question, TCP has a bunch of “magic > > numbers” whose best values vary depending upon the source you consult. > Use the source; specifically Linux or your favorite BSD. You can > probably grep the code for those RFC numbers. > > Wes Felter - [EMAIL PROTECTED] - http://felter.org/wesley/ > > _______________________________________________ > p2p-hackers mailing list > [email protected] > http://lists.zooko.com/mailman/listinfo/p2p-hackers > _______________________________________________ p2p-hackers mailing list [email protected] http://lists.zooko.com/mailman/listinfo/p2p-hackers
