This is the lower 32 bits of a 64-bit counter tallying total Ethernet frames received over the radio link itself, split for the same reason as the dropped-frames counters; the MIB predates 64-bit counter types and needed to split large totals across LSB and MSB object pairs. It matters as the denominator against which gnEthStatisticDroppedPacketsLsb and its MSB counterpart should be compared to compute a meaningful frame-loss percentage for the link, rather than looking at absolute drop counts in isolation. An admin calculating link quality would combine this value with its MSB counterpart, gnEthStatisticRadioReceivedFramesMsb, to get total received frames, then divide the combined drop count by that total.