This read-only value reports the Leaf Initiated Join (LIJ) ID for the point-to-multipoint (PMP) SVC rooted at this interface, the identifier a leaf uses when it dynamically joins an existing multipoint call rather than the root explicitly adding it. This lets the switch and an admin correlate a specific leaf's join request back to the multipoint tree it attached to, which is useful for multicast-style ATM services like video distribution where leaves come and go. An engineer auditing which leaves joined a video-distribution PMP SVC dynamically versus were statically provisioned would inspect cktAtmLijId to trace the join event.