EIGRP QUESTION

[townsendrs]

We have 4 sites on our WAN. Sites B C and D all connect to Site A via p2p T's, also sites B and C connect to site D through another set of p2p T-s.

Our routers all have eigrp setup, my question is: if the link between Site A and B goes down, is the purpose of eigrp to route traffic from Site B to Site A via SITE D? (confused yet?) I guess what I'm saying is, is the purpose of eigrp to find alternate routes to the destination when physical alternate routes do exist?

Thanks for explaining this.

[thisisshanky]

Yes EIGRP will converge to the next successor (feasible successor, if any). Feasible successor is the backup route (if any exists) that eigrp calculates and stores in its topology table. For a route to be a feasible successor it needs to satisfy the feasibility condition.

More on this can be read at the Cisco website.

Also, if a route cannot be a feasible successor, and when the primary fails, eigrp will query its neighbors for an alternate route, and if one exists, the network will converge through that route.

So the answer is yes, EIGRP will help in reachability of packets from site B to A, through site D.