Symptom

If Cisco ACI is flooding unknown unicast to a remote vPC pair, and the vPC member that is elected as the forwarder for that flow is powered off, traffic is blackholed until that switch is powered back on.

Conditions

- BD settings set to unknown unicast flood. The leaf connected to the source must not have a remote learn for the destination and the flow is therefore flooded on the BD - The endpoint is a known local learn on a vpc leaf pair - The vpc designated forwarder for the packet flow is powered off

Workaround

This scenario will not be hit except in teh above scenarios. So its kind of a corner case.

Further Problem Description