EIGRP Notes - Message Types

Please correct if I’m being stupid…which is a lot of the time.

Hello : Discovers and maintains neighbors

Destination:  224.0.0.10
Important fields:
  K values

Update : An update to the topology such as a route withdrawal or a metric change

Destination:  224.0.0.10 -or- unicast during neighbor discovery
Important fields:
  Message sequence number
  Route being updated including k values to compute metric

Query : Used to ask a neighbor if it has a route to a certain network; see casino online for free stuck-in-active

Destination:  224.0.0.10
Important fields:
  Message sequence number
  Network being queried

Reply : Sent in response to a query message telling a router whether or not it has a route

Destination:
Important fields:
  Message sequence number
  Sequence number of message to ack
  Network being queried along with k values to compute metric

Ack : Used to acknowledge updates, queries, replies

Destination: Unicast address of router
Important fields:
  Sequence number of message to ack