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EIGRP - EIGRP Fundamentals

6 important questions on EIGRP - EIGRP Fundamentals

In EIGRP the terms Successor and Successor Route are used, what do they mean?

1. Successor Route is the route with the lowest Metric to reach a destination.
2. Successor is the first next-hop router for the Successor Route.

In EIGRP, what is the difference between the Feasible Distance and the Reported Distance.

The Feasible Distance is the lowest metric a path has for a destination.
This turns into the Reported Distance when it is advertised to it's neighbors.

In EIGRP, what is the Feasibility Condition?

It is the condition of a route path, where it's Reported Distance is less then the Feasible Distance of the active route path.

A Feasible Successor is a route that satisfies the Feasibility Condition, where is it used for?

It is used as a backup route, where the Feasibility Condition ensures a loop-free path.

EIGRP contains a topology table, which makes it different from a true Distance Vector routing protocol. What are 4 properties of each entry in the table?

1. Network Prefix
2. EIGRP neighbors that advertised that prefix
3. Metrics from each neighbor (Reported Distance, Hop Count, etc.)
4. Values used for Metric calculation (Load, Total Delay, Min. Bandwidth)

EIGRP uses IP Protocol Number 88 and when possible uses multicast address 224.0.0.10. Which 5 different packets does it send using this?

1. Hello (Discovery of neighbors and detecting they are offline)
2. Request (Used to get specific information from specific neighbors)
3. Update (Used to transmit routing and reachability info)
4. Query (Sent out to search for another path during reconvergence)
5. Reply (Sent in response to a Query packet)