EIGRP - Routing Protocols and Concepts - page 410

Example 9-4 Feasible Distance and Successors in the HQ Routing Table

HQ# show ip route
<output omitted>

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 9 subnets, 5 masks
D 10.0.0.0/8 is a summary, 00:31:59, Null0
C 10.10.0.0/22 is directly connected, FastEthernet0/0
C 10.10.4.0/22 is directly connected, FastEthernet0/1
D 10.10.8.0/23 [90/3847680] via 172.16.1.34, 00:04:30, Serial0/0/1
D 10.10.10.0/23 [90/3847680] via 172.16.1.34, 00:04:30, Serial0/0/1
D 10.10.12.0/24 [90/5514496] via 172.16.1.38, 00:04:25, Serial0/1/0
D 10.10.13.0/24 [90/5514496] via 172.16.1.38, 00:04:25, Serial0/1/0
D 10.10.14.0/25 [90/7181056] via 172.16.1.42, 00:04:25, Serial0/1/1
D 10.10.14.128/25 [90/7181056] via 172.16.1.42, 00:04:25, Serial0/1/1
172.16.0.0/16 is variably subnetted, 4 subnets, 2 masks
D 172.16.0.0/16 is a summary, 00:31:59, Null0
C 172.16.1.32/30 is directly connected, Serial0/0/1
C 172.16.1.36/30 is directly connected, Serial0/1/0
C 172.16.1.40/30 is directly connected, Serial0/1/1
209.165.201.0/30 is subnetted, 1 subnets
C 209.165.201.0 is directly connected, Serial0/0/0

What is the IP address of the successor for network 10.10.8.0/23? 172.16.1.34, which is B1

What is the feasible distance to 10.10.8.0/23? 3847680

What is the IP address of the successor for network 10.10.14.128/25? 172.16.1.42, which is B3

What is the feasible distance to 10.10.14.128/25? 7181056

What is the IP address of the successor for network 10.10.12.0/24? 172.16.1.38, which is B2

What is the feasible distance to 10.10.12.0/24? 5514496

Feasible Successors, Feasibility Condition, and Reported Distance

Briefly explain the term feasible successor .

A feasible successor is a backup path to other routers maintained in a separate table so that DUAL
does not have to be recomputed when the successor becomes unavailable. A feasible successor satis-
fies the feasibility condition.