Re: Very poor TCP/SACK performance

David S. Miller (davem@dm.cobaltmicro.com)
Tue, 8 Sep 1998 05:06:40 -0700


Date: Tue, 8 Sep 1998 15:57:57 +0400
From: Savochkin Andrey Vladimirovich <saw@msu.ru>

Well, I can confirm that the default rmem setting is insufficient
for a stream of small packets (524 bytes here).

David, it's not the first report about "strange" throughput for
streams of small packets. What do you think about changing default
window size or default receive buffer size?

The problem is, with the default settings we are pretty safe about
buffer overcommit. It also makes "I'm going to send you out of order
segments only" type attacks less easy (although these are not all that
interesting since the attacker has to give away his identity to
perform the attack unlike SYN floods and the like).

I don't know, perhaps Alan can comment.

Later,
David S. Miller
davem@dm.cobaltmicro.com

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