Subject: Re: TCP_MSS to 1460 in tcp.h or /etc/netstart?
To: Ken Hornstein <>
From: Ronald Khoo <>
List: tech-net
Date: 10/26/1997 07:09:02
> In the absense of TOS queuing, I don't
> >see how it matters much if an interactive packet is stuck behind 3 500
> >byte packets or one 1500 byte one.)
> With all due respect ... I've tried it both ways, and it _does_ make
> a difference for me.

Are you using NetBSD ? (as your slip/ppp router, that is :-)
If so, you *do* have a primitive form of TOS queuing.
(vi /sys/net/if_{ppp,sl}.c and search for IPTOS_LOWDELAY)

So it *would* make a difference cos your interactive packet would be
stuck behind just one 296 (576?, whatever you use) byte packet rather
than a 1500 byte one.  At 9600bps, that would be .3s compared with 1.5s
which is VERY noticeable :-)  But speeds are higher today.  Let's say
56k ISDN at 7000 cps.  That would be 0.04s compared with 0.2s which is
still somewhat noticeable.

But only for character-interactive traffic.  Today's net has very
little such, what with the web being the dominant traffic.  So
it matters to far fewer people (as a percentage) now.

Ronald Khoo <> Voice: +44 181 371 1000 Fax: +44 181 371 1150