bge & vlan stranges

[Terry Lambert]

Boris Kovalenko wrote:
>   I have Compaq DL360G2 with Broadcom BCM5701 Gigabit Ethernet and
> FreeBSD 5.1R installed. There are no problems if I use bge as usual
> network card, but when I try to use 802.1Q vlans, I can't receive (only
> receive, sending is ok) packets more then 1456 bytes! What is the
> problem? BGE driver, VLAN driver or my network configuration?

The encapsulation information is subtracted from your available
MTU, so that is correct.

Some cards have a bogus feature that lets you send longer frames
than the normal MTU, but you can't rely on this feature being
interoperable between card vendors, or being supported on all
cards.

I suppose you want to do this because you are trunking a channel
that goes to a border device, and for some reason you have disabled
receipt of all ICMP, instead of only abusable ICMP, and thus you
have broken end-to-end path MTU discovery.

It would be best if you were to simply fix your ICMP.

-- Terry