Description

Once EIGRP neighbor relationships are established, the exchange of routing information begins. EIGRP uses Update packets to exchange this information. All the routing information received from neighbors is stored in an EIGRP topology table. EIGRP uses DUAL to calculate best routes to remote networks. In order for a route to be inserted into the routing table, it must satisfy the feasibility condition, which is used to prevent loops in the EIGRP networks. The route with the lowest metric to the destination becomes a candidate to be inserted into the routing table. If any routes remain, they must satisfy the feasibility condition to become a backup route to the destination network, should the primary route become unavailable.
To calculate the cost for each destination network, EIGRP uses a sophisticated metric, which is by default, composed of bandwidth and delay.
|n When EIGRP is deployed in larger networks, you need to optimize the default EIGRP behavior to achieve desired scalability. By implementing EIGRP stub configuration, you can limit EIGRP query range, making EIGRP more scalable with fewer complications. By using summarization, you can reduces the size of the routing tables and optimize the exchange of routing information between the routers. To utilize available redundant links, EIGRP by default supports load balancing across multiple links. To improve network utilization, you can also configure EIGRP to utilize unequal-cost load balancing.
|n This course explains how EIGRP chooses the best path through the network and also how to configure stub routing, route summarization, and load balancing with EIGRP.