Allied Telesis AT-S63 - Manual (Page 300)

Chapter 17: MSTP
300 Section II: Advanced Features
Path Cost
Specifies the path cost from the bridge to the regional root. If the
bridge is the regional root, the value is 0.
Associated VLANs
Specifies the VIDs of the VLANs that have been associated with
the MSTI ID.
The table does not include the CIST. The table is empty if no MSTI
IDs have been created.