Symptom

1. The output of "show interface trunk" on Nexus7000 with VPC might end up showing both sides of the VPC having different vlans in forwarding state. Example: ------------ Switch_A -------------------------------------------------------------------------------- Port Vlans in spanning tree forwarding state and not pruned -------------------------------------------------------------------------------- Po3 2-402,666,777 Switch_B -------------------------------------------------------------------------------- Port Vlans in spanning tree forwarding state and not pruned -------------------------------------------------------------------------------- Po3 none 2. Might experience some multicast traffic outage on downstream switch as traffic might be getting dropped on the port-channel showing above details.

Conditions

- Switch running 6.2(8) - VPC is configured - VTP / VTP pruning is configured. - vPC primary leg flaps.

Workaround

1. Flapping the secondary vPC peer leg would make VTP recompute pruning states and joined vlans are unpruned thus flooding multicast traffic on that vlan. 2. Turning off pruning is another alternative, that would start flooding all the multicast traffic on that port.

Further Problem Description

Further Problem Description