It's my understanding that MSTP switches must have the following identical information configured in order for it to participate in a region:
- Configuration revision
- VLAN-to-MSTI mapping
Do all VLANs need to be created on all switches in the region? For instance, if I have two distribution layer switches and twelve access layer switches, each one with two connections to the distribution layer, do *all* VLANs defined in access switch #1 need to be defined in all access layer switches? Or just the VLANs that are shared network-wide? The specific situation I am trying to figure out is if I have an SVI (for routing) created in one switch, the VLAN for that SVI is never going to be used elsewhere in the network. Does that VLAN need to be created everywhere or is it enough to just add it into its own instance which designates that switch as the root for that instance?