This counter tracks packets dropped because the router's internal forwarding queue was full when the packet arrived. This is a capacity/congestion indicator rather than a configuration or link-quality issue -- it means packets are arriving faster than the router can process and forward them, typically during traffic bursts that exceed the unit's throughput on a low-bandwidth satellite link. A site whose Rx data rate is provisioned at only a few hundred kbps but which receives a sudden burst of LAN-originated traffic destined for satellite might see this counter jump, indicating the router queue backed up faster than the satellite uplink could drain it.