Chapter 7 - EIGRP

autonomous system (AS)

A set of routers running the same routing protocol under a single realm of control and authority.

feasible distance

the metric value for the lowest-metric path to reach a destination.

Feasibility Condition (FC)

A condition under which, for a route to be considered a backup route, the reported distance received for that route must be less than the feasible distance calculated locally. this logic guarantees a loop-free path.

Feasible Successor (FS)

a route that satisfies the feasibility condition and is maintained as a backup route.

hello packets

packets that are sent out at periodic interval to detect neighbors for establishing adjacency and ensuring that neighbors are still available.

Hello timer

the amount of time between the advertisement of hello packets and when they are sent out an interface.

K values

values that EIGRP uses to calculate the best path.

reported distance

the distance reported by a router to reach a prefix. the reported distance value is the feasible distance fro the advertising router.

successor

the first next-hop router for the successor route.

successor route

the route with the lowest path metric to reach a destination.

Summarization

A method of reducing a routing table by advertising a less specific network prefix in lieu of multiple more specific network prefixes.

Topology table

A table used by EIGRP that maintains all network prefixes, advertising EIGRP neighbors for prefixes and path metrics for calculating the best path.

variance value

The feasible distance (FD) for a route multiplied by the EIGRP variance multiplier. Any feasible successor's FD with a metric below the EIGRP variance value is installed into the RIB.

wide metric

A new method of advertising and identifying interface speeds and delay to accounts for higher-bandwidth interface (20 Gbps and higher).