With the kernel datapath, OVS relies on the kernel datapath for ICMP needs frag handling on a tunnel interface. However, with the userspace datapath, where there is no actual IP stack, depending on the configuration these packets get dropped, or end up with the kernel through the bridge interface.

Maybe we can still leverage the kernel infrastructure by pushing back the ICMP messages, as we already use the kernel for the routing and arp resolution, so maybe it can also handle the PMTU part for us.

We need to research what would be the best solution, and implement this. OVN relies on PMTU and not having this breaks the OVS-DPDK OSP workers ability to adjust the MTU.