This read-only counter counts AAL5 CPCS protocol data units that were ready to transmit on an AAL5 ATM virtual channel but were deliberately dropped, even though no transmission errors occurred, typically because the outgoing interface ran out of buffer space. Network staff monitor this to detect when an AAL5-carrying interface is oversubscribed rather than experiencing line errors, which points them toward a capacity problem instead of a cabling one. A steadily increasing count on a VCC carrying a video stream would suggest the interface buffer is too small for the offered load and needs either more buffering or admission control.