This read-create enumerated value configures the ABR Number of cells a source may send between each forward Resource Management (RM) cell. An admin tunes this to control the frequency of RM-cell feedback relative to data cells - a smaller value gives more frequent congestion feedback at the cost of slightly more RM-cell overhead. For example, on a connection needing tighter congestion responsiveness, the admin might choose a smaller value like nrm2 so feedback cells are generated more often relative to data traffic.