Spanning-tree port role - NXOS/VPC

[kella3]

Hello there,

was there any change to how peer-link port roles are marked on VPC pairs between the 7.X.X versions and 9.X.X+ ? I inherited two pairs of N9Ks, one is running the older code, and marks the peer link as Root, whereas the pair running 9.X.X is marking the peer link as Designated. Am I looking at a potential misconfiguration (didn't find anything obvious yet), or did Cisco just change the way these are marked. Both pairs are running same STP mode, and have "peer-switch" in the vpc domain.

Thanks !

[MHM Cisco World]

I think for both Ver. it same, 
the Peer-link between two NSK SW 
the primary NSK Peer-link side will be Root 
the Secondary NSK Peer-link side will be Designated 

[M02@rt37]

Hello @kella3,

In Cisco Nexus switches, including Nexus 9000 series switches, the behavior and port roles for the peer-link in a vPC configuration have not changed significantly between the 7.x.x and 9.x.x+ software versions. The peer-link is typically assigned the role of "Root" or "Designated" based on the STP priorities and path costs.