In specific deployments, e.g., with BGP EVPN configured for OVN logical switches / routers (the BGP control plane is executed outside of OVN), OVN owned MAC addresses should be advertised to the fabric (EVPN).

OVN should provide a way for users to configure an OVN logical switch to install (Linux) FDB entries into the table of a Linux bridge that's used by the control plane (e.g., FRR) to advertise MAC addresses through EVPN.

Notes on potential implementation details:

• OVN already supports dynamic route redistribution - blackhole routes are injected through netlink into the VRF associated to an OVN router that has dynamic route redistribution enabled
• this mechanism could be extended to allow injecting static Linux FDB entries into such VRFs - the control plane (e.g., FRR) would then take care of advertising these mac addresses through EVPN
• a prerequisite seems to be that a loopback interface must exist (e.g., created by the CMS) and must be attached to the Linux bridge used by FRR for EVPN; static FDB records must be added using this loopback interface

E.g., simulate the effect of ovn-controller injecting an FDB entry for a MAC on VNI 20:

vni=20
podman exec $h1 bridge fdb add 00:01:84:84:84:$vni dev lo-$vni master static