Current count, from CMTS initialization, of contention minislots
utilized on the upstream logical channel. For contention regions,
utilized minislots are those in which the CMTS correctly received
an upstream burst from any CM on the upstream logical channel.
This is the 64 bit version of docsIfCmtsUpChnlCtrUsedCntnMslots,
and will not be accessible to SNMPv1 managers.
Support for this object is mandatory.