I have an MST region with istance 1 mapped to vlans 1-500. The MST boundary switch has an interface which connects to another switch running PVST.
My question is, when a BPDU is sent from within the MST instance 1 for VLAN 45 (for example), will the PVST region recieve BPDUs for just VLAN 45 or for all VLANs mapped to the MST instance (1-500)?
I am confused by this line in the 6500 series command reference guide;
"The ports that belong to the MST switch at the boundary simulate PVST+ and send PVST+ BPDUs for all the VLANs."
Any help would be much appreciated!
The Cisco MST switch detects neighbor running PVST as soon as it received a PVST BPDU. Then, it replicates the BPDU for instance 0 (the CIST) on each an every vlan configured on the port. This is a boundary port, meaning that only the CIST information is relevant (your MST instance 1 information will not be used). So on the PVST switch, each vlan receives a BPDU coming from the MST bridge, and each vlan instance receives information from MST instance 0.