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Date: Thu, 16 Jul 2015 15:53:08 +0100
From: Karl Pielorz <kpielorz_lst@tdx.co.uk>
To: John-Mark Gurney <jmg@funkthat.com>
cc: freebsd-net@freebsd.org
Subject: Re: lagg of em0/em1 + VLAN = lower MTU?
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--On 13 July 2015 09:56 -0700 John-Mark Gurney <jmg@funkthat.com> wrote:

> You can fix the untagged traffic on lagg0 with something like the
> following:
> route change <destination> <gateway> -mtu 1500
>
> You can see which routes need to be changed w/ the netstat -rWnfinet
> command...

Ok, that works. It's clunky - but it works...

> You should be able to make it work, but it definately needs more work
> to make it work automaticly...  There was a recent change that went
> in that makes changing lagg mtu easier, but I think that's only in
> HEAD right now...

Presumably, other people configuring it don't run into the issue 
(lagg+VLAN) because of different FreeBSD version / NIC's?

Is the issue just that the VLAN code thinks the LAGG is the parent, and 
doesn't "see" the underlying card is long-frame capable?

Or is it as simple as the em cards not being listed as 'long-frame capable' 
(i.e. from the man page).

> Hope this helps...

Certainly appears to have, thanks!

-Karl