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EIGRP Topology

We have two routers 1 and 2 connected by tow links one is  ds3 and other is T1 link.

Eigrp is running on these two links and neighbor relationship has been establised.

Router 2 has learned network A via redistribution from another router Rouer 3.

now if we see the topology table information on router 1 and 2 for network A , here is what I get

on router 2

Network A  (5376,3840)  from interface pointing to router 3

Network A ( 31232,19668) from T1 interface pointing to Router 1           ------------------->  Looks like Router 1 is sending back the subnet to R2 ?

On router 1

Network A ( 19968,5376)   from DS3 connected to R2  ---------> learned from router 2

Network A ( 30976,5376)  from T1 connected to R 2

Diagram looks like below reported dist and feasible dist are as shown.

|               | (19968,5376)

| Router 1  |<-------------------------------------- DS3 -------------------------------------->|                 |

|               |                                                                                         |                 | (5376,3840)

|               |                                                                                         |  Router 2  | <-----------------> Router 3

|               |<-------------------------------------- T1------------------------------------------>|                 |                       Network  A is here

|               |  (30976,5376)                                             (19968,31232)  |                 |

Doesn't it looks like a loop?

Please share the experience.




EIGRP Topology


it seems like normal behaviour and as Feasability condition is the loop prevention in EIGRP, there  will be no problem.



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Re: EIGRP Topology

Agreed. Operating as designed. R2 has two paths in the topo table, with the path thru R3 being the successor which will be installed in the rib. The second path thru the T1 to R1 will not be used unless really strange things happen. R1 has two paths in the topo table with the best one pointing thru the DS3 to R2 which will be installed in the rib. The second path on R1 is pointing thru the T1 to R2 and is feasible, so it would be used immediately if the primary link thru the DS3 were to go down. It R1 failed over to the T1 link due to failure of the DS3, R1 would first end out a poison update (infinity) to remove R2's path thru the T1.

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