This object reports, and in one specific case controls, the operational state of a port-mirroring session. It automatically becomes active(2) once both a destination and at least one source port are assigned, reads negative(1) otherwise, and the only value an admin may actually write is clear(3), which wipes the session's configuration and returns it to negative(1). For example, an admin sets tpPortMirrorSessionState to clear(3) on a session to remove its destination and source-port assignments and reset it for reuse.