This attribute is indicative of the number of frames discarded because
the size of the out bound frame exceeded the message transfer unit (mtu)
allowed for the bridge port. Note that this counter only refers to the
outbound frames for this bridge port. This counter wraps around its
maximum value of 4294967295.
This counter is influenced by the attribute fragmentIp. This counter is
incremented when the a frame larger than the mtu allowed is
encountered and cannot be fragmented. If this counter is increasing
steadily, it might be useful to set the value of the attribute fragmentIp to
a value of on.