This notification-only enumerated value carried in session-end and session-failed traps gives the reason a mirroring session ended, such as userRequest(1), idleTimeout(4), adminReset(6), or portAdministrativelyDisabled(22), with the analyzer left to interpret it as either an access or packet session event. An admin uses this to distinguish an intentional, expected session end (like userRequest or adminReset) from an unexpected failure (like nasError or lostCarrier) when auditing mirroring session history. For example, juniPacketMirrorTerminationReason=idleTimeout(4) on a session-end trap confirms the mirrored subscriber's session simply timed out from inactivity rather than being forcibly cut off by an administrator.