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New Member

EIGRP Topology Table

I'm getting a little confused about the EIGRP topo table. The successor is the best route to a destination. The feasible succesor is the next best route to a destination as long as it's AD is less than the FD. When you do a "show ip eigrp topo", and it shows the topology table, do they consider all routes in here to be feasible successors? Lets say that for a 10.200.1.6, it saids it has one successor, but shows two routes. Looking through Cisco eyes, are both of those routes considered feasible successors, and of course the one with the lowest FD is the successor and is put in the routing table? Or...out of those two routes, does Cisco considered one to be a successor, and one to be considered a feasible successor. The later is how I thought Cisco looked at it. However, I was reading in one of the CCIE books, and it "seemed" like it was saying both routes in the topo table are considered feasible successors, and then the one with the lowest AD is also the successor and is put into the routing table. So what I'm asking is lets say I was given a topo table and CISCO asks how many feasible successors does this destination have and which route is it it? Lets say it shows the destination to have one successor, but it shows two routes. So are there two feasible successors with one being the successor, or is there one successor and one feasible successor. Does Cisco consider them segregated?

2 REPLIES

Re: EIGRP Topology Table

Hello,

is this a question for an exam ? If you have the following example:

P 172.16.100.0/24, 1 successors, FD is 2707456

via 172.16.250.2 (2707456/2195456), Serial0

via 172.16.251.2 (46251776/281600), Serial1

If the question is: how many feasible successors do you have, my answer would be that this destination has two feasible successors. If the question is: how many successors do you have, my answer would be one.

HTH,

GNT

New Member

Re: EIGRP Topology Table

Ok, so even though the first router in your example is the successor, its also considered a feasile successor?

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