Hi All,
When we configured a double-sided VPC it is keep going suspended in Nexus 9k.
We have verified the configuration on the physical & port-channel interfaces, everything found correct.
Verified the VPC-Peer link configuration and found correct.
When checked the " sh lacp neighbor interface port-channel xx" on both the VPC pairs ( Switch "A"&"B" and Switch "C"&"D" ), all of them are showing same "Partner System-ID".
PROBLEM : We used the same "VPC Domain-ID" on both the pairs of the switches ( Switch "A"&"B" with VPC domain-id as 10 and Switch "C"&"D" with VPC domain-id as 10 )
The vPC domain ID should be unique in the contiguous Layer 2 network. Problems arise when you use the same vPC domain ID for more than one vPC pair of switches.
A unique vPC domain ID is required because the domain ID is used in order to generate the system ID for many processes, such as Link Aggregation Control Protocol (LACP).
Required Recommendation: Always use different domain ID in double-sided vPC topology and in vPC for DCI topology.
VPC System-Mac and vPC Local System-Mac :
Once configured, both peer devices use the vPC domain ID to automatically assign a unique vPC system MAC address, as defined below: vPC system-mac = 00:23:04:ee:be:<vpc domain-id in hexadecimal> For instance, vPC domain 10 will result in vPC system-mac of 00:23:04:ee:be:0a.