This read-only Counter tallies the number of frames discarded on ingress specifically because of a shelf alarm condition; it is not supported on FRSM12. An administrator monitors this to detect frame loss caused by shelf-level alarm conditions rather than by traffic-shaping or queue-depth issues on the channel itself. For example, a burst of rcvFramesDiscShelfAlarm counts coinciding with an active shelf alarm elsewhere in the chassis would confirm the alarm, not channel congestion, is the cause of that traffic loss.