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Subjecttcp_timestamps + VJ compression = trouble
Hi,

It seems that when tcp_timestamps are enabled, the throughput with PPP (at
least ISDN) breaks together when VJ compression is used.
Peter de Vrijer investigated the problem, and found the following data:

tcp_sack tcp_timetamps
1 1 slow, bursts with normal speed
0 0 fast, 7 to 8 kbytes/sec
1 0 fast, 7 to 8 kbytes/sec
0 1 slow, 1 to 2 kbytes/sec

This indicates that when tcp_timestamps is enabled, and VJ compression is
used, the throughput is horrible. I've personally found the same problem
on my system, using both the isdn version used in 2.2.1, and updated to
the latest CVS version. I have no experience with normal PPP throughput,
and can't easily test this, but highly suspect that this will have the
same problems.

The problem can't be found with 2.0.36, and this seems to support the data
found here, since that doesn't have tcp_timestamps in the first place.

I hope this helps, and that the problem can be fixed,

Bas Vermeulen

--
When I shop for hardware I always look for the "Designed for Windows 95" logo.
I really thank Microsoft(TM) for encouraging manufacturers to label their
products this way, so I know what to AVOID.

I stick to quality software:

Linux 2.2.1 | IBM OS/2 Warp (TM) v4.0




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