This Counter32, indexed by ifIndex, counts receive end-of-list interrupts, meaning the hardware ran out of receive descriptors on this radio interface, and like the other counters in this table it only ever increases until the interface or agent resets. Because it reflects a hardware/driver-level fault rather than ordinary traffic, a sudden increase (as opposed to slow, steady growth) is worth alerting on - it typically points to a wedged radio chip, RF calibration trouble, or a driver bug rather than to normal load.