very slow network between 2.1.127 and PC/TCP [lost cause?]

Jim Partan (partan@mit.edu)
Sun, 08 Nov 1998 12:17:27 EST


Hi,

I've been using 2.0.35 on a pentium 90 with a 3c509 (driver built as a
module) for a while, transferring files to an old msdos 6.22 box running
PC/TCP software (OnNet 1.2 -- broken) also with a 3c509. Normally I get about
100kb/sec between these boxes (but up to 1000kb/sec between the p90 and other
linux, solaris or sunos boxes).

When I upgraded the p90 to 2.1.127 (also tried 2.1.125 and 2.1.126), the
ftp transfer rates to the msdos box dropped to about 3kb/sec. Other
connections are more or less at their 2.0.35 speed. The 2.0.35 kernel
does _NOT_ have CONFIG_INET_PCTCP set.

The PC/TCP software is OnNet 1.2 (PC/TCP Network Software 3.1). The
Configure.help file says that all versions of PC/TCP up to OnNet 2.0 are
broken, but it looks like CONFIG_INET_PCTCP has been commented out in the
2.1.x Config.in file, and removed from the code.

I looked in net/ipv4/tcp_input.c in both 2.0.35 and 2.1.127 to see
where the support for broken PCTCP stacks might go (about 2 lines in
2.0.35), but the 2.1.x networking has changed enough that it wasn't
at all clear to me where the support would go. Since the 2.0.35 kernel
doesn't even have CONFIG_INET_PCTCP set, re-incorporating this config
option into 2.1.127+ might not even help in cases like mine.

I have tcpdump logs of ftp transfers to the msdos box with both 2.0.35
and 2.1.127 on ftp://uam.whoi.edu/pub/ftplogs in case anyone
is interested. Also, if there is other information which would be helpful,
please let me know.

If the net maintainers feel that it would be too annoying or disruptive to
maintain the support for the broken PCTCP versions, I can definitely
understand that --- I'm certainly trying to get rid of that DOS box as soon
as I can.

thanks very much for any help!

Jim
partan@mit.edu
(please cc any replies to me)

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