[31] in linux-net channel archive
silly window syndrome on linux?
daemon@ATHENA.MIT.EDU (Arnt Gulbrandsen)
Tue Jan 24 15:50:04 1995
Date: Tue, 24 Jan 1995 20:06:02 +0100 (MET)
From: Arnt Gulbrandsen <agulbra@nvg.unit.no>
To: linux-net@vger.rutgers.edu
I think that's what I've been seeing the last minutes.
I just brought up a dial-up PPP link, 28.8 bps between two linux
machines, both running 1.1.83. My FTP server and client both use large
windows.
FTP across the PPP link (no other hops) moves along fine until the
sending side gets into FIN_WAIT1, then it spurts and waits.
Typical case: FTP transfer moves along smoothly until there's 25591 bytes
in the send queue. FIN_WAIT has been entered by this time. An eternity
later (minutes, quite likely), the send queue moves down to 24155 bytes.
It stays there, then suddenly it jumps down to 15539, stays there a
little, 12667, then it goes down to 0 and is in TIME_WAIT for a short
while. This is quite reproducible.
Now, I'm listed as one of the authors of tcp.c, which is not really an
accurate representation of reality. I admire those who can understand its
intricacies, but I myself am a little scared of those 4000 lines, and my
part in it is limited to one small (and not even very good) function. So
would someone else kindly meditate over why linux does this? Alan? Matt?
I can supply much more detailed data, for instance /proc/net/tcp output
every second, or even accounts on both systems if necessary.
--Arnt
