eigrp route guidelines...

                                         general george s. guideline

3

neighbor discovery
   potential neighbors are discovered via hello exchanges

topology exchanges
   when neighbor's come up, complete topologies are exchanged, thereafter, partial updates based on topology changes only

route selection
   the router reviews it's topology table and selects the best route to each network (subnet, broadcast domain, vlan)

the neighbor table lists the neighbors

the topology table contains the topologies learned from the neighbors

the route table contains the best routes

update messages can be sent on multicast 224.0.0.10