The total number of packets that higher-level protocols
requested be transmitted, and which were addressed to a
multicast address at this sub-layer, including those that
were discarded or not sent. For a MAC layer protocol, this
includes both Group and Functional addresses.
Discontinuities in the value of this counter can occur at
re-initialization of the management system, and at other
times as indicated by the value of
ifCounterDiscontinuityTime.