*BSD News Article 25474


Return to BSD News archive

Path: sserve!newshost.anu.edu.au!munnari.oz.au!sgiblab!spool.mu.edu!caen!nic.umass.edu!ymir.cs.umass.edu!gaia!doyle
From: doyle@gaia (Jim Doyle)
Newsgroups: comp.os.386bsd.bugs
Subject: [ FreeBSD ] CSLIP w/ MTU > 296
Date: 31 Dec 1993 17:40:44 GMT
Organization: CS Dept., Umass-Amherst
Lines: 20
Message-ID: <2g1o6sINNbjo@ymir.cs.umass.edu>
Reply-To: doyle@cs.umass.edu
NNTP-Posting-Host: gaia.cs.umass.edu
X-Newsreader: TIN [version 1.2 PL0]

I installed the FreeBSD-1.0-RELEASE kit on a 386. It behaves fines however the
SLIP code seems unable to work with MTU > 296.  In two cases, I built a 
generic kernel and hardcoded the MTU (edit the SLMTU constant in 
/sys/net/if_sl.c) for 552 and 1500 byte MTUs.  When I dial into the campus
server and connect, it only works for the default 296 byte MTU.

Interestingly... slattach does not write an acknowledgement to the console
what it has set the line discipline for sl0 for MTU=552,1500. sl0 is marked up,
but when I try to ping the server host, or any other addresses that map out the
default route through SL0 - no traffic ever hits the wire.

My SLIP server at campus works with larger MTUs - because I've run at 552 and
1500 bytes from the SPARC I have at home.. 

If anyone else has encountered this problem, let me know.  I will go have a 
look at if_sl.c and slattach this weekend and see if I can fix the problem.
I may just say screw it and get the LBL CSLIP 2.7 code running in FreeBSD.

-- Jim D (doyle@cs.umass.edu)