This attribute specifies the type of spanning tree protocol the port is
participating in. A bridge port could participate in either the ieee8021
spanning tree protocol or the dec spanning tree protocol. If the value of
the attribute protocolSpec in the SpanningTreeProtocol component,
provisioned under the TransparentBridge component is in conflict with
the value of this attribute, the value of the protocolSpec attribute will
prevail. Prevailing stp type is reflected in the value of the attribute
stpTypeOper.