MSTP/4/PROPDISC:OID [oid] The MSTP Process's Port has
been set to discarding state. (ProcessID=[INTEGER], InstanceID=[INTEGER],
PortID1=[INTEGER], PortID2=[INTEGER], PortID3=[INTEGER], PortID4=[INTEGER],
PortIDFlag=[INTEGER], IfIndex=[INTEGER], PortState=[INTEGER], PortName=[STRING])
MSTP进程的链路状态发生变化,端口状态变为Discarding状态。