Migrating cores, trying to get first uplink of a port in a port channel to forward faster than standard spanning tree.

[pcweber]

I am migrating from an Avaya dual core pair to a Cisco Dual core. Have an uplink port on each switch, both in same port channel. (Switches running VSS). My challenge is to cutover the first port I plug in takes the standard 45 seconds before forwarding. I have tried  “Spanning-tree portfast network” on the ports themselves. It made no diff in the period before spanning tree began to forward.

If I add that portfast network config it to the port channel I get a Bridge assurance blocking the port channel and the port channel goes down. So that don’t work.

Any ideas even to temporarily configure the first port in the port channel so that it forwards faster so I can cut faster and can even go back and put safer config back? (Note, these ports are VLAN tagged with multiple vlans. Ac

[paul driver]

Hello
Are these collapsed distribution/cores?
I assume with the way your migrating is a piecemeal approach.

Do you have a L2 connection between the exiting core and the new-core, if you do make sure you have all the L3 svi on the new core in a shutdown state and your not looping back into the exiting core with the new core.

Are you ruining any IGP on the existing core?

[pcweber]

yes, the cores are bridged. We have many closet stacks migrated. So that is not an issue. We are down to the data center switches and of course we have scheduled downtime but no one wants the network down then because they are pushing application updates, etc. So, my challenge is swinging from old core uplinks to new core uplinks and not loosing 9-10 pings/ forwarding if there is a possible way to not wait the normal spanning tree period on a VLAN tagged uplink that is a member of a port channel.

[pcweber · Accepted solution]

I just figured it out. If this spanning tree setting is added the port channel begins forwarding immediate. Can use it to cutover, then remove.

spanning-tree portfast edge trunk