On Wed, 2011-05-18 at 12:20 +0100, Guido Trotter wrote: > On Mon, May 16, 2011 at 10:12 PM, Stephen Fromm <[email protected]> wrote: > > This forces the interface of a newly created interface of a > > KVM instance to be the same as that of the bridge. On RHEL5 > > and RHEL6, the MTU for the bridge interface will be set to the > > lowest MTU of its constituents. If the newly created tap interface > > has an MTU of 1500 and the bridge has an MTU of 9000, the bridge > > MTU will be lowered to 1500. Inside the instance, you will be > > unable to transmit 9k packets out the supposedly jumbo-packet-capable > > interface. By setting the MTU of the tap interface to the same > > as the bridge before adding it, I can transmit 9k packets from > > the instance off the bridge. > > --- > > Hi, > > The code itself looks good. I'm just wondering if we're sure it > couldn't break any existing setup > (if so we need to find a way to make it optional). Does the mtu of the > interface "inside" the instance need any changes for this to work?
Yes, the interface inside the instance still has to be configured for the correct MTU. If I leave the inside interface at MTU 1500, I cannot pass jumbo packets across that interface and the bridge. Regards, sf
