Date: Thu, 4 Nov 2004 13:44:44 +0000 From: Matthew Seaman <m.seaman@infracaninophile.co.uk> To: Jan Knoppers <knoppers@astent.nl> Cc: freebsd-questions@freebsd.org Subject: Re: Is UDP header compression (RFC 2508) supported in FreeBSD Message-ID: <20041104134444.GA4296@happy-idiot-talk.infracaninophile.co.uk> In-Reply-To: <001501c4c258$c7d74120$9600000a@Desktop> References: <20041104095710.GA659@happy-idiot-talk.infracaninophile.co.uk> <001501c4c258$c7d74120$9600000a@Desktop>
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On Thu, Nov 04, 2004 at 11:26:42AM +0100, Jan Knoppers wrote:
>=20
> >> Look at the Authors of that RFC.
> >>=20
> >> Compare it with this statement in ppp(8):
> >>=20
> >> vjcomp
> >> Default: Enabled and Accepted. This option determines if
> >> Van
> >> Jacobson header compression will be used.
>=20
> My understanding is that this vjcomp statement relates to TCP/IP header
> compression only as described in RFC 1144 (Jacobson, V., "TCP/IP Compress=
ion
> for Low-Speed Serial Links", February 1990). This RFC explicitly excludes
> UDP/IP header compression. RFC 2508 is intended to fill this gap.
>=20
> So, you may very well be right, and I hope you do, but I do not see it
> documented.
Good point. Looking at /usr/src/usr.sbin/ppp/vjcomp.c it does appear
to only affect the headers. Probably your best bet would be to ask
the last committer to work on that code directly -- see the
README.changes file in that directory.
That's the usermode PPP implementation, but the alternative kernel
mode pppd(8) doesn't appear to have had much work done on it for some
time. That's just VJ header compression too.
Cheers,
Matthew
--=20
Dr Matthew J Seaman MA, D.Phil. 26 The Paddocks
Savill Way
PGP: http://www.infracaninophile.co.uk/pgpkey Marlow
Tel: +44 1628 476614 Bucks., SL7 1TH UK
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