EIGRP Question ???

daras

I cannot understand this question so if you can help me i would appreciate.

Based on the topology table that is shown and assuming tha variance is not configured which route or routes should appear in the routing table ?

R1#show ip eigrp topology
IP-EIGRP Topology Table for AS(100)/ID(192.168.8.21)

P 192.168.2.0/24 1 successors FD is 2707456
via 192.168.8.22 (2707456/2195456) serial0/0
P 192.168.8.20.30 1 successors FD is 2169856
via connected serial0/0
P 192.168.8.16/30 1 succesors, FD is 3789824
via connected serial0/2
P 192.168.8.24/30 1 successors FD is 2681856
via 192.168.8.22 (2681856/2169856) serial0/0
via 192.168.8.18 (4301824/2169856) serial0/2

Answer: 192.168.8.24/30 [90/2681856] via 192.168.8.22 serial 0/0

I cannot understand how it gets into that conclusion

What about the other routes are they satisfying the Feasibility condition

1.AD is 2195456 > FD 2707456 so NO
2. We dont care about the directly connected
3. The AD of the other is 2169856 < FD 2681856 since variance is not used we cannot have both so we select which one ?


Please hellp !!!!!!

NetworkVeteran

I rarely encounter EIGRP these days but let me take a stab--

daras wrote: »

P 192.168.8.20.30 1 successors FD is 2169856
via connected serial0/0
P 192.168.8.16/30 1 succesors, FD is 3789824
via connected serial0/2

These are directly connected point-to-point networks. Connected networks are more preferred (lower Administrative Distance in Cisco parlay) than routes imported from EIGRP, so the routing table won't be accepting these entries anytime soon.

P 192.168.2.0/24 1 successors FD is 2707456
via 192.168.8.22 (2707456/2195456) serial0/0

I'd expect this to go in. The route is passive, AD=2,195,456 < FD 2,707,456, and the next-hop router is directly connected. I also don't see anything indicating that a better path to that prefix is known.

P 192.168.8.24/30 1 successors FD is 2681856
via 192.168.8.22 (2681856/2169856) serial0/0
via 192.168.8.18 (4301824/2169856) serial0/2

I'd expect only the 192.168.8.22 entry to go in, because you stated that variance is disabled so there's no unequal-cost load sharing, and that path has the lowest feasible distance by a wide margin.

Answer: 192.168.8.24/30 [90/2681856] via 192.168.8.22 serial 0/0
1.AD is 2195456 > FD 2707456 so NO

Both the answer and your math seem off.