This is a live count of EIGRP packets sitting in the outbound queue for one specific peer, waiting their turn to be transmitted. A queue that stays non-zero or keeps growing for a peer indicates that interface or peer cannot drain packets as fast as EIGRP generates them -- often the first visible sign of an EIGRP peer under CPU or bandwidth pressure. For instance, seeing this value sit at 40+ toward one neighbor while others show 0 would point an admin straight at that specific adjacency during a routing instability investigation.