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Date:      Fri, 28 Apr 1995 11:27:29 -0700
From:      Rick Jones <raj@hpisrdq.cup.hp.com>
To:        bugs@FreeBSD.org
Subject:   Possible bug in the 4/12 TCP
Message-ID:  <9504281827.AA05655@hpisrdq.cup.hp.com>

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Here is the original message, with my typo...

rick jones


 To: Andras Olah <olah@cs.utwente.nl>
 Cc: rstevens@noao.edu (Richard Stevens), bugs@frteebsd.org
 Subject: Bug?: immediate ACK's in 4/12 TCP...
 Date: Fri, 28 Apr 1995 11:23:37 -0700
 From: Rick Jones <raj@hpisrdq.cup.hp.com>


Andras -

Thanks for the copy of tclient and tserver. They confirm something
that I have noticed with netperf (which I have working again with
minor tweaks to netperf.c and netserver.c so that a TCP_TRR test calls
the tran routines and not the conn routines - what's RCS anyway :)

There is (what I think is) a bug in the 4/12 TCP, of unknown origin.
It is immediately ACKing *all* traffic. I have analyser traces of
netperf TCP_RR, TCP_TRR, TCP_CRR, and TCP_STREAM tests which show this
behaviour. I'm going to try to find time to look through the source to
see if I can find the bug. 

I think I'll also ask bugs@freebsd.org if any other changes were added
to TCP for the 4/12 snapshot to try and narrow my search. Bugs - what
were the changes in the TCP code between the 3/22 and 4/12 snapshots?

For TCP_RR, it means a 2x increase in packets per transaction, for
TCP_TRR, things go from three packets per transaction to five. For a
TCP_STREAM test, it is a 33% increase in packets. I suspect that it
can be seen with just about *any* TCP connection - telnet, ftp,
etc...I expect to have the 2.0PL1 netperf on ftp.cup.hp.com by Monday.

later,

rick





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