Subject: Re: TCP_NODELAY and full links (was Re: sup problems?)
To: None <>
From: Feico Dillema <>
List: current-users
Date: 09/29/1999 21:04:24
On Wed, Sep 29, 1999 at 11:27:06AM -0700, Jason Thorpe wrote:
> On Wed, 29 Sep 1999 03:03:33 +0200 
>  Feico Dillema <> wrote:
>  > I think (but am certainly not sure) that FreeBSD has PMTU discovery on
>  > by default now. That's how I discovered it was off by default in
>  > NetBSD. I wondered what was the cause of the performance difference
>  > between FreeBSD and NetBSD on a 100Mbs Etherlink. Switching on 
>  > PMTU disc. seemed to make up for most of it.
> Are the two on the same subnet?  If so, it shouldn't matter at all.  What
> is the configuration?

No, there was one FreeBSD machine as router in between. This happened
some time ago, and I don't have the same hardware running anymore to 
try and repeat it. We replaced the network cards in these machines as
they were pretty bad and causing trouble. So, I might very well not
be able to reproduce this. I believe it was more a broken
hardware/driver issue than a TCP implementation issue. Although
switching on PMTU disc improved performance, it wasn't the direct
cause of the relatively bad performance...

If I can get hold of a machine with one of these old cards, I can 
see if I can reproduce it and find out what really went on...