cmVBridgePII is a read-only integer identifying the specific network interface -- by shelf, slot, port, and user channel -- that a given virtual bridge table entry describes. An administrator uses this to locate which physical DSL or Ethernet interface's bridging statistics a particular row of the table represents. For example, when investigating bridging behavior on a specific subscriber line, the operator would match its shelf/slot/port location against cmVBridgePII to find the corresponding statistics row.