This is the 32-bit running count, since CMTS initialization, of contention mini-slots on which the CMTS detected a burst but could not correctly receive it, i.e. a collision between two or more modems transmitting in the same slot; support for this counter is optional and it returns zero if unsupported. An admin watches this as a direct measure of contention collisions, and a persistently high collision rate suggests too many modems sharing too few contention opportunities, a signal to tune backoff windows or add capacity.