Indicates the operational status of the port for the
MST protocol.
edge -- this port is an edge port for the MST region.
boundary -- this port is a boundary port for the
MST region.
pvst -- this port is connected to a PVST/PVST+ bridge.
stp -- this port is connected to a Single Spanning
Tree bridge.
This object is only instantiated when the object value
of stpxSpanningTreeType is mst(4).
This object is deprecated and replaced by
stpxSMSTPortStatus.