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Date: Fri, 10 Jul 2015 11:06:27 -0700
From: John-Mark Gurney <jmg@funkthat.com>
To: Karl Pielorz <kpielorz_lst@tdx.co.uk>
Cc: freebsd-net@freebsd.org
Subject: Re: lagg of em0/em1 + VLAN = lower MTU?
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Karl Pielorz wrote this message on Fri, Jul 10, 2015 at 14:04 +0100:
> This works fine. If I add a VLAN now to that, I end up with:
> 
> "
> lagg0.10: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 
> 1496
> ...
> inet x.x.x.x
> ...
>         vlan: 60 parent interface: lagg0
> "
> 
> 
> The MTU on lagg0.10 has shrunk by 4 (size of VLAN tag). Is there a way of 
> avoiding that?

Try bumping the MTU on the root em's by 4 (1504) before creating the
lagg...

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."