MST with VSS and Nexus vPC

[Andrew Bailey]

I am migrating to MST in my network. I am running a 6513 VSS core with multiple Nexus 5k distribution switches. The Nexus switches have a vPC back to the VSS. So essentially my whole network is 1 logical topology and from what I am understrand  there is no reason benefit to use multiple instances of MST.

According to, http://www.cisco.com/en/US/prod/collateral/switches/ps9441/ps9670/C07-572834-00_STDG_NX-OS_vPC_DG.pdf   I am going to map all the VLANs except the nexus internal reserved VLANs to MST instance 1.

So here is my VSS core MST configuration

          spanning-tree mst configuration

          name MST1

          revision 1

          instance 1 vlan 1-3967,4048-4094

          spanning-tree mst 0-1 root primary

          spanning-tree mode mst

Nexus Distribution and access MST configuration

          spanning-tree mst configuration

          name MST1

          revision 1

          instance 1 vlan 1-3967,4048-4094

          spanning-tree mode mst

I guess I am just looking to confirm/validate what I am doing looks right/is the best practice and I am not missing anything. Thanks.

[graham smart · Accepted solution]

Seems fine to me.

We also use MST in our DC's with VSS and N5ks..

We havent had any issues and your config seems fine.

MST/Spanning tree is really only going to be enabled / used to prevent badly configured switches. It shouldnt cause any problems re:VSS. So yeah.

Enable it, Create one instance, Chuck all your vlans in it and pow.. Job done.. never to be thought about again.

-Graham
Please note: My comments are simply suggestions. I cannot be held liable for any loss of data, life or marbles due to following my instructions.

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