I've been reading Cisco documentation regarding MST - PVST+ interoperation and have some questions as I am about to do this in a production environment.
In our environment (PVST+), we often manually exclude unwanted VLANs from our trunks (as shown below):
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,300,404,405,455,474,700,800,1001-1005
switchport mode trunk
We are looking to implement MST as such:
spanning-tree mst configuration
instance 1 vlan 1-300
instance 2 vlan 301-4094
We do this kind of VLAN filtering at nearly all of our closets. The Cisco document at the following URL shows that trunks should carry all VLANs mapped to an instance.
So according to everything that I see and provided that I use the MST configuration above, I would need to remove VLAN filtering from the trunks for this to work properly.
Am I correct on this?