[ovs-discuss] OVN - MTU path discovery

[Ben Pfaff]

On Thu, Jul 12, 2018 at 04:03:33PM +0200, Miguel Angel Ajo Pelayo wrote:
> Is there any way to match packet_size > X on a flow?
> 
> How could we implement this?

OVS doesn't currently have a way to do that.  Adding such a feature
would require kernel changes.

You mentioned ICMP at one point.  It would be pretty easy to implement
such a feature specifically for ICMP to logical router IP addresses in
OVN, because we could just slow-path such traffic to ovn-controller
(maybe we already do?) and check the packet size there.  I don't know
whether there's value in that.