We got one cloud of metro Ethernet consist of 2 unit of 7613 as NPE. Both have serve 5 customers and each of customers are connected via UPEs in separate ring to the both NPE. The issue is both NPE are running MSTP.
For instance 0 = all vlans
instance 1 = vlan 100
instance 2 = vlan 200
All UPEs except 1 ring of customers are using PVST.
That 1 ring customer are using MSTP same like both NPEs.
It happens that trunk between the NPE_A & NPE_B are disconnected.
All customers UPE that running PVST are experience port status "BLK" at the each ring .
Except the one UPE that running MSTP, all UPE in the ring are forwarding.
Why this issue happen in customer that tunning PVST?
Any interoperability issue between PVST & MSTP?