This read-only counter tracks the number of valid routing table entries that were deliberately discarded anyway, for instance to free up buffer space for other, presumably more needed, routing entries. An admin seeing this counter climb would suspect the routing table is under memory pressure and being forced to evict valid routes, which could cause intermittent reachability issues to the discarded destinations. For example, a rising count here on a device with a large and actively changing CLNS network might indicate its routing table size limit is being reached and should be increased if possible.