On Sun, Mar 09, 2003 at 02:25:25PM +0100, Iljitsch van Beijnum quacked:
On Sat, 8 Mar 2003, Joe St Sauver wrote:
you will see that for bulk TCP flows, the median throughput is still only 2.3Mbps. 95th%-ile is only ~9Mbps. That's really not all that great, throughput wise, IMHO.
Strange. Why is that? RFC 1323 is widely implemented, although not widely enabled (and for good reason: the timestamp option kills header compression so it's bad for lower-bandwidth connections). My guess is that the OS can't afford to throw around MB+ size buffers for every TCP session so the default buffers (which limit the windows that can be used) are relatively small and application programmers don't override the default.
Which makes it doubly a shame that the adaptive buffer tuning tricks haven't made it into production systems yet. It was a beautiful, simple idea that worked very well for adapting to long fat networks: http://www.acm.org/sigcomm/sigcomm98/tp/abs_26.html -dave -- work: dga@lcs.mit.edu me: dga@pobox.com MIT Laboratory for Computer Science http://www.angio.net/ I do not accept unsolicited commercial email. Do not spam me.