When a router running EIGRP considers alternate paths, which ones will it consider loop-free?
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A. B. C. D.B.
EIGRP (Enhanced Interior Gateway Routing Protocol) is a distance-vector routing protocol used in computer networks to help determine the best path for forwarding IP packets. EIGRP selects the best path based on a composite metric, which includes bandwidth, delay, reliability, load, and maximum transmission unit (MTU).
When a router running EIGRP considers alternate paths, it first calculates the feasible distance (FD) and the reported distance (RD) for each path. The feasible distance is the best metric of all the paths to reach a particular network, while the reported distance is the metric advertised by the neighboring router.
In order to ensure loop-free paths, EIGRP uses a Diffusing Update Algorithm (DUAL) to find the best loop-free path. When considering alternate paths, EIGRP only considers those that meet the feasibility condition, which is determined based on the RD and FD values.
To meet the feasibility condition, the reported distance (RD) of the alternate path must be less than the feasible distance (FD) of the current best path. This is because the feasible successor is an alternate path that meets the feasibility condition and provides a loop-free backup path to the current successor path.
Therefore, the answer to the question is B. EIGRP will only consider alternate paths that have a reported distance less than the feasible distance of the current best path.