Catalyst core and Meraki running on PVST and RSTP

[13jobsp90]

I have a catalyst switch 4506 which is the core switch running on PVST and it is connected to Meraki Switch (RSTP) in tower 2, the core switch is in tower 1 and it is connected to access switches under it. Tower 2 is full of meraki switches. So then I pass the trunk allowed vlans from core switch to meraki (the existing vlans in tower 1 not all some of them) & for tower 2 new set of vlans. Some of the tower 1 vlans are getting flapped in tower 1 access switches. If I remove the tower 1 vlans in meraki this will not happen (flapping will not occur in tower 1). What is the issue for this?

[marce1000 · Accepted solution]

 - Generally a common spanning tree algorithm should be configured on all switches on the intranet,

  M.

[13jobsp90]

can u pls explain? what to do in catalyst switches & meraki switches?

[Giuseppe Larosa · Accepted solution]

Hello @13jobsp90 ,

@marce1000 's suggestion is to run the same type of STP in all parts of your network.

Cisco switches can run MST. If you use MST with only instance 0  the so called CST you have a single instance Rapid STP that can be a better fit for Meraki Rapid STP.

The alternative is to have a different sets of VLANs in tower2 but if you need to extend some VLANs on both towers you can think of moving to MST single instance all the Cisco switches in tower 1.

Hope to help

Giuseppe