- The DUAL algorithm is recomputed to find an alternate route.
- The best alternative backup route is immediately inserted into the routing table.
- The router will query neighbors for an alternate route.
- The router uses the default route.
Explanation: Because EIGRP uses the DUAL algorithm, the router is able to maintain information on all potential loop-free backup routes. In the event of the failure of a routing table entry, the router immediately inserts the best backup route into the routing table.