What is the difference between EIGRP neighborship and adjacency, and how do they form?

Understanding the Difference Between EIGRP Neighborship and Adjacency

When it comes to EIGRP (Enhanced Interior Gateway Routing Protocol), two important terms that often come up are neighborship and adjacency. Let's explore the difference between the two and how they are formed in the context of EIGRP.

EIGRP Neighborship

In EIGRP, neighborship refers to the relationship between two routers that are directly connected and have exchanged information with each other. When two routers become neighbors in EIGRP, they can begin exchanging routing information to learn about the network topology.

EIGRP Adjacency

On the other hand, EIGRP adjacency is a more advanced state of connectivity between two routers. Adjacency is formed when the neighboring routers have successfully exchanged and agreed upon all the routing information, including metrics and paths, leading to a higher level of synchronization between the routers.

Forming EIGRP Neighborship and Adjacency

Neighborship in EIGRP is typically formed through the exchange of Hello packets between directly connected routers. Once the routers discover each other and establish a neighborship, they can begin exchanging routing updates.

For EIGRP adjacency to form, the routers must go through a process of exchanging Update and Query packets to synchronize their routing tables completely. This process includes verifying the received information, calculating metrics, and agreeing on the best paths.

In conclusion, while EIGRP neighborship is the initial step of connectivity between routers in EIGRP, adjacency represents a more advanced level of synchronization and routing information exchange. Understanding the difference between these two terms is crucial for effectively managing EIGRP networks.