Network & Infrastructure / EVPN, VXLAN & Data Center Fabrics
EVPN route scale and hidden neighbor-table exhaustion
BGP remains healthy as tenant endpoints grow, but newly learned hosts fail to forward. Hardware MAC, neighbor or next-hop limits can be reached before the control-plane route limit.
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
Record control-plane route counts alongside hardware FDB, ARP/ND, next-hop and VRF utilization. Inspect installation failures and compare a newly failing endpoint with an older working one.
Explain the result
Different tables consume different resources, and a shared hardware partition can constrain one feature earlier than expected. A received route count alone is not a capacity measure.
Plan the fix
Model endpoint, subnet and multihoming growth against actual platform resource allocation. Reduce unnecessary state or expand capacity using the approved architecture rather than periodically clearing tables.
Check the result and rollback
Validate new endpoint installation and a failure-induced state increase with reserve headroom. Revert changes if resource repartitioning removes capacity required by another active feature.