This counter tracks otherwise-good frames that were discarded because of unavailable resources. Since the frame itself was valid, this points to the router running out of internal buffer or processing capacity to accept it -- an internal capacity limit rather than a link-quality or configuration issue, worth correlating with the FIFO-overrun counter to see if the same resource pressure is causing both. This counter climbing during a burst of inbound Ethernet traffic that coincides with heavy satellite-side processing would suggest the router's shared internal resources, not the Ethernet link itself, are the constraint.