[openstack-dev] [TripleO][Neutron] PMTUd broken in gre networks

Rick Jones rick.jones2 at hp.com
Wed Jan 22 16:26:06 UTC 2014


On 01/22/2014 03:01 AM, Robert Collins wrote:
> I certainly think having the MTU set to the right value is important.
> I wonder if there's a standard way we can signal the MTU (e.g. in the
> virtio interface) other than DHCP. Not because DHCP is bad, but
> because that would work with statically injected network configs as
> well.

Can LLDP be used here somehow?  It might require "stretching"  things a 
bit - not all LLDP agents seem to include the information, and it might 
require some sort of "cascade."  It would also require the VM to pay 
attention to the frames as they arrive, but in broad, hand-waving, 
blue-sky theory it could communicate maximum frame size information 
within the broadcast domain.

rick



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