Two L3 uplinks per node, address on dummy0, BGP unnumbered to the fabric, and Cilium peering with the node’s own FRR over a single ::1 session that carries both address families — so no Kubernetes manifest ever contains a TOR address.
Dual-homed servers use IP-unnumbered physical interfaces. A dedicated dummy interface (not lo) is assigned to each server as its IPv4 node address. FRR runs between the servers and the ToR switches to provide node-level connectivity, advertising the server’s node IP (dummy interface address) and receiving the default route from the ToRs. Using a bond interface between ToRs can also be used for redundancy and failover for server connectivity. You may also configure Layer 3 interfaces. The main issue is about node identity and service continuity during the failure of a single link. Using a bond interface or a dummy interface seems like a more usable approach. ...