General

customer found defect

Symptom

In a VPC topology where two switches have a single link to a third switch or host as well as `no lacp suspend-individual` is configured. If we keep the links physically connected but remove LACP port-channel config on one of the member links from the host side, the configured link will flap and go into individual state. However, additionally, the port-channel will flap on both vPC switches after an extra link failure, resulting in black-holing of the traffic through this vPC. This behavior was not seen in late 9.3.x code but appears to have changed in 10.2.x code. Tested in 10.2.5 but may be seen in other similar code points as well.

Conditions

- Nexus 9000 switches in VPC mode on 10.x code - no lacp suspend-individual present for the members of the port-channel - VPC between two peers and a 3rd device (switch or end host) - unconfigure the LACP port-channel config on the remote end, resulting in the link being in individual state on the Nexus side

Workaround

Avoid using `no lacp suspend-individual` on the Nexus side for these interfaces, if they will be unconfigured from the LACP port-channel while still up. The issue is not seen when lacp suspend-individual is on by default.

Further Problem Description