Best practice to migrate PVST+ to MST on a network with VPC and Fabricpath with VPC+

[zahid.kalwar]

We need best practices to migrate PVST+ to MST on a network with VPC and Fabricpath with VPC+.

[balaji.bandi]

It all depends on where are you deploying what kind of segment is this?

is this Enterprise LAN  or DC Environment?  how big is the network

Fabircpath is a new world, all your legacy may not have support. you need to have latest device and code to support.

[zahid.kalwar]

Thanks Balaji.

Please see below;

It is DC with 2 x Nexus 7018 Switches and 12 x 56128 Nexus switches with Fabric path.

Thanks,

ZK

[lucasfreitas83 · Accepted solution]

Hello zahid.kalwar,

Each environment has one design, but follow best pratices that MSP with VPC.

MST and vPC Best PracticesWhen configuring MST with vPC, you should follow the same best practices as for Rapid PVST+. In addition, you should follow these practices:●Associate the root and secondary root role at the aggregation layer and it is preferred to match the vPC primary and secondary roles with root and secondary root.●You do not need to use more than one instance for vPC VLANs.●Make sure to configure regions during the deployment phase.●If you make changes to the VLAN-to-instance mapping when vPC is already configured, remember to make changes on both the primary and secondary vPC peers to avoid a Type-1 global inconsistency.●Use the dual-active exclude interface-vlancommand to avoid isolating non-vPC VLAN traffic when the peer link is lost.EtherChannel Misconfiguration GuardA dispute mechanism was introduced for the Cisco Catalyst 6500 Series Switches in Cisco IOS®Software Release 12.2(18)SXF for MST and in Cisco IOS Software Release 12.2(33)SXI for Rapid-PVST+, prior to the introduction of vPC to deal with a scenario such as the one described here.If upstream switch1 and switch2 are not configured for vPC, but the downstream access switches (switch3 and switch 4) are configured with PortChannel mode on, then broadcast frames will loop back, causing duplicates as depicted in Figure 9. The misconfiguration guard takes down the PortChannel on the downstream switch to avoid this scenario.The misconfiguration guard detects this scenario by seeing BPDUs with different Bridge IDs that originate on both PortChannel links.

https://www.cisco.com/c/dam/en/us/products/collateral/switches/nexus-7000-series-switches/C07-572834-00_STDG_NX-OS_vPC_DG.pdf

Please rate and mark posts accordingly if you have found any of the information provided useful.
It will hopefully assist others with similar issues in the future.

Best regards,
Lucas Freitas