Re: How to setup Jumbo Frames? NetBSD Dom0 and FreeBSD XENHVM

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Thu, Jun 27, 2013 at 04:47:10AM +0000, Mike C. wrote:
> 
> Hi,
> 
> First, sorry if I'm asking something basic.
> 
> I have a re1 interface that supports jumbo frames (MTU up to 7422), the
> card is set up correct, however I need a bridge for xen!
> 
> When I try to change the bridge mtu settings:
> # ifconfig bridge0 mtu 7422
> ifconfig: SIOCSIFMTU: Network dropped connection on reset
> 
> However ifconfig shows the mtu at 7422:
> # ifconfig bridge0                                                        
> bridge0: flags=0 mtu 7422
> 
> And the biggest problem comes when I try t start a domu... if the
> bridge0 interface has a mtu different than 1500 I can't start the domu,
> because the virtual interface creation fails with:
> 
> brconfig: add xvif5i0: Invalid argument

I guess you could change the /usr/pkg/etc/xen/scripts/vif-bridge
script to set the mtu of the xvif before adding it to the bridge.

But I'm not sure that the netfront/netback (at last as implemented
on NetBSD) supports MTU larger than 4k.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--