RE: 2.4 tcp very slow under certain circumstances (Re: netdev issues (3c905B))

[Vibol Hou]

It looks like the patch fixed the problem.  TCP communications over modem
seems fine now with the same settings that didnt' work earlier.

-Vibol

-----Original Message-----
From: David S. Miller [mailto:[e-mail]]
Sent: Wednesday, February 21, 2001 2:57 AM
To: [e-mail]
Cc: Vibol Hou; Linux-Kernel; [e-mail]
Subject: Re: 2.4 tcp very slow under certain circumstances (Re: netdev
issues (3c905B))

Ookhoi writes:
 > We have exactly the same problem but in our case it depends on the
 > following three conditions: 1, kernel 2.4 (2.2 is fine), 2, windows ip
 > header compression turned on, 3, a free internet access provider in
 > Holland called 'Wish' (which seemes to stand for 'I Wish I had a faster
 > connection').
 > If we remove one of the three conditions, the connection is oke. It is
 > only tcp which is affected.
 > A packet on its way from linux server to windows client seems to get
 > dropped once and retransmitted. This makes the connection _very_ slow.

:-( I hate these buggy systems.

Does this patch below fix the performance problem and are the windows
clients win2000 or win95?

--- include/net/ip.h.~1~	Mon Feb 19 00:12:31 2001
+++ include/net/ip.h	Wed Feb 21 02:56:15 2001
@@ -190,9 +190,11 @@

 static inline void ip_select_ident(struct iphdr *iph, struct dst_entry
*dst)
 {
+#if 0
 	if (iph->frag_off&__constant_htons(IP_DF))
 		iph->id = 0;
 	else
+#endif
 		__ip_select_ident(iph, dst);
 }