Question

A data center engineer is troubleshooting an ACI fabric where an endpoint in EPG-Web on Leaf-101 sends an ARP request for an endpoint in the same bridge domain that is currently unlearned by the fabric. The bridge domain is configured with ARP Flooding disabled and L2 Unknown Unicast set to Hardware Proxy. How does the ACI fabric handle this ARP request?

Accepted Answer

The spine proxy (COOP database) is consulted to resolve the target, and the ARP is unicasted to the destination leaf if the endpoint is known; otherwise it is dropped.

Answer

The ARP request is flooded to all leaf switches in the bridge domain using the BD GIPo multicast group.

Answer

The ingress leaf broadcasts the ARP to all ports in the EPG only, without involving the spine.

Answer

The ARP request is silently dropped because ARP Flooding is disabled, preventing any resolution.