Core migration SVI first or STP

[axeleratorcisco]

I have a new virtualized Coreswitch on top my current two Core switches. The new virtualized Coreswitch now has all physical connectivity to the WAN devices. Basically it's sitting in between the current routing Cores and WAN devices.

I want to migrate the SVIs over to the new virtualized Core, and make that new virtualized Core the STP root.

What is the best order / way of doing things?

Disable SVIs/routing first on old cores and activate it on the new Core, and THEN move the Spanning Tree Root role to the new Core?

Or is it better to start with STP and THEN SVI/routing?

[Jon Marshall]

It does depend somewhat on your network topology but generally speaking I always sort out STP first because nothing flows across your network until it has done it's job. 

Don't forget that traffic does not have to go via the root for that vlan, STP is simply making sure there are no loops involved. 

Jon

[axeleratorcisco]

The current Cores are running VRRP, Core1 is active Core2 is standby. All VLANs are in one instance. The rest is typical, distribution switches per building with the access layer below.

My thoughts were:

Disable layer3 / routing on Core2, since it's not doing anything.

Disable layer3 on Core1, while simultaneously enabling SVIs and routing on the new virtualized Core.

Verify if traffic is flowing to all SVIs on the new virtualized Core.

Change STP priority of Core2 to that of a regular switch, change Core1 STP priority to that of a regular switch while simultaneously making the virtualized Core the root bridge.

Sounds good?