I have some questions about using MSTP between Cisco (3750, 3560, and 2960) and Meraki MS425's. I currently have a 6509E core acting as root bridge. The entire network is running rapid-pvst. The topology is simple with the 6509 at the core and a single fiber connection from there to the edge switching in each building. There are no redundant paths between the core and edge switches. I need to replace the 6509 with a Meraki 425 stack which will need to the root bridge. The 425 cannot be root when using rapid-pvst on the edge switches. I have been doing some testing with a 3750 trunked to my 425 stack and if I just change the mode from from rapid-pvst to mst, the 3750 shows that the 425 is root over mst0 which includes all vlans. I have been told not to use mst0 so I created instance 1 and mapped all vlans to that but when I do that the Meraki only has root over mst0. Mst1 that I created has the 3750 as root. I have the following questions:
1) In my scenario is it ok to just use the default mst0 instance with all vlans mapped to it?
2) I don't explicitly allow the native vlan (vlan1) on the trunks. Do I need to add that?
3) I have switchport trunk allow statements an all my trunks. Do I need to go through and allow all vlans on those trunks?
