Network & Infrastructure / EVPN, VXLAN & Data Center Fabrics
Missing EVPN Type-3 routes and silent BUM loss
Known unicast works across the fabric, but a new host cannot resolve its neighbor or receive broadcast traffic. Missing replication membership can affect discovery before any remote MAC is learned.
Environment and inputs: BGP EVPN overlays on a routed underlay; supported route types and multihoming behavior depend on the network OS. Diagnostic/design example; not tested on production equipment.
Collect the evidence
Inspect inclusive multicast routes, replication lists, bridge membership and BUM counters for the affected VNI. Compare a working VNI on the same underlay to isolate tenant-specific state.
Explain the result
BUM delivery depends on replication membership and the selected transport design. A valid known-unicast Type-2 route does not prove that unknown unicast, broadcast or multicast reaches every remote segment.
Plan the fix
Repair the intended ingress-replication or multicast membership design and confirm the VNI has consistent participating VTEPs. Avoid flooding all tenants through a shared catch-all bridge.
Check the result and rollback
Test a new endpoint discovery and expected broadcast delivery, then check duplicate rates. Revert if replication expands beyond tenant membership or produces a storm during host churn.