Skip site navigation (1)Skip section navigation (2)
Date:      Wed, 29 Aug 2001 08:29:09 +0200
From:      "Peter Blok" <pblok@inter.NL.net>
To:        "'Mike Tancsa'" <mike@sentex.net>, "'Garrett Wollman'" <wollman@khavrinen.lcs.mit.edu>
Cc:        <freebsd-net@FreeBSD.ORG>
Subject:   RE: Runt frames = broken VLAN ?
Message-ID:  <001001c13053$e9ea74c0$8a02a8c0@ntpc>
In-Reply-To: <5.1.0.14.0.20010828160054.01accec0@marble.sentex.ca>

next in thread | previous in thread | raw e-mail | index | archive | help
Mike, et al.

I had the panic too. The problem is the order of initialization. It only
happened when you compile NETGRAPH support in the kernel instead of using it
as a module. When initialize netgraph a little bit later it works fine. In
netgraph.h there is a macro called NETGRAPH_INIT. I have changed the
SI_ORDER_ANY to SI_ORDER_LAST or SI_SUB_PSEUDO to something else (I can't
remember).

I am using the module. I'll check on this today and get a proper answer.

Peter
-----Original Message-----
From: owner-freebsd-net@FreeBSD.ORG
[mailto:owner-freebsd-net@FreeBSD.ORG]On Behalf Of Mike Tancsa
Sent: Tuesday, August 28, 2001 22:11
To: Garrett Wollman
Cc: freebsd-net@FreeBSD.ORG
Subject: Re: Runt frames = broken VLAN ?


At 12:54 PM 8/28/01 -0400, Garrett Wollman wrote:
><<On Tue, 28 Aug 2001 01:05:32 -0400, Mike Tancsa <mike@sentex.net> said:
>
> > Can anyone tell me why the VLAN code might be causing my switches
(ciscos)
> > to see a lot of runt frames when the interface is in 802.1q trunking
> mode ?
>
>It's possible that the Cisco is (bogusly, IMHO) trying to enforce the
>Ethernet minimum frame length on the *de*capsulated frames.  If you
>send a frame that's less than 60 octets long, it gets encapsulated
>(adding another four octets) and then padded by the interface up to 64
>octets.  After the encapsulation is removed by the receiver, the frame
>appears to only be 60 octets long.
>
>I'd call it a Cisco bug.  The minimum frame length in Ethernet arises
>from the electrical parameters of the original CSMA/CD Ethernet
>design; what matters is the number of clocks the transmitter is
>active, not the length of the payload.

If its a Cisco bug, would it not manifest it self consistently ?  On other
ports, I have a 3620 and another catalyst both in 802.1q trunking mode, but
I dont see any runt frames there.

Also, who is the VLAN maintainer these days ?  I ran into a panic that I
thought was netgraph related, but Archie Cobbs thinks it might be in the
VLAN code. I filed a PR on the issue

http://www.freebsd.org/cgi/query-pr.cgi?pr=30149

I saved the debug kernel as well as the core dump in case its needed, but
the problem is easy enough to repeat.

         ---Mike


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-net" in the body of the message


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-net" in the body of the message




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?001001c13053$e9ea74c0$8a02a8c0>