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Nexus 7K VPC to CatOS STP problems


I'm in the process of migrating from two Catalyst 6509s running CatOS to a pair of Nexus 7009s in a VPC domain. The current Cat 6509 environment is running PVST+ and the STP priority is 8192 for all vlans. The N7Ks are running Rapid-PVST+ with an STP priority of 40960 for all vlans. After connecting one of the Cat 6509's (switch 1) to both Nexus 7Ks via a VPC I see strange issues with STP. Both the 6509s STP configurations looks normal with Cat 6509 switch 1 being the root bridge. However if I run 'show spanningtree root' on each Nexus 7K, they are also both root bridges for all vlans (I have peer-switch configured) even though the priorities are set higher. The other strange problem is that only vlan 1 is trunking between the N7Ks and Cat 6509 switch 1, I can see that all vlans are trunking when I run 'show int trunk', the VPC is also up and happy.

I would appreciate any help with this.

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