This object specifies the initial number of FEC redundancy
bytes the ATU-C appends to downstream frames transmitted over
the fast channel during the training sequence. The ATU-C can
fallback from this value depending on the aggregate data rate
achieved during training.
It is desirable to choose a large FEC size, thereby increasing
the chance of being able to correct errors in the data delivered
by a frame. However, additional FEC redundancy bytes increases
frame overhead, and thus frame latency.