EIGRP uses 5 packet types in communication with its neighbours. The packet types are detailed below –
- Hello — EIGRP uses hello packets in the discovery of neighbors. They are multicast to 220.127.116.11. By default, EIGRP sends hello packets every 5 seconds (60 seconds on WAN links with 1.544 Mbps speeds or less).
- Acknowledgment — An acknowledgment packet acknowledges the reception of an update packet. It is a hello packet with no data. EIGRP sends acknowledgment packets to the unicast address of the sender of the update packet.
Related – EIGRP Stub
- Update — Update packets contain routing information for destinations. EIGRP unicasts update packets to newly discovered neighbors; otherwise, it multicasts update packets to 18.104.22.168 when a link or metric changes. Update packets are acknowledged to ensure reliable transmission.
- Query — EIGRP sends query packets to find feasible successors to a destination. Query packets are always multicast.
- Reply — EIGRP sends reply packets to respond to query packets. Reply packets provide a feasible successor to the sender of the query. Reply packets are unicast to the sender of the query packet.