Information Technology Reference
In-Depth Information
Task 10: Determine Whether R1 Is a Feasible Successor for
the Route from R2 to the 192.168.1.0 Network
A feasible successor is a neighbor who has a viable backup path to the same network as the successor.
To be a feasible successor, R1 must satisfy the feasibility condition. The feasibility condition (FC) is
met when a neighbor's reported distance (RD) to a network is less than the local router's feasible dis-
tance to the same destination network.
Examine the routing table on R1.
Step 1.
R1#
show ip route
<output omitted>
172.16.0.0/16 is variably subnetted, 4 subnets, 3 masks
D 172.16.0.0/16 is a summary, 00:42:59, Null0
C 172.16.1.0/24 is directly connected, FastEthernet0/0
D 172.16.2.0/24 [90/40514560] via 172.16.3.2, 00:43:00, Serial0/0/0
C 172.16.3.0/30 is directly connected, Serial0/0/0
D 192.168.1.0/24 [90/2172416] via 192.168.10.6, 00:42:26, Serial0/0/1
192.168.10.0/24 is variably subnetted, 3 subnets, 2 masks
D 192.168.10.0/24 is a summary, 00:42:20, Null0
C 192.168.10.4/30 is directly connected, Serial0/0/1
D 192.168.10.8/30 [90/3523840] via 192.168.10.6, 00:42:20,
Serial0/0/1
What is the feasible distance to the 192.168.1.0 network?
2172416
Examine the routing table on R2.
Step 2.
R2#
show ip route
<output omitted>
10.0.0.0/30 is subnetted, 1 subnets
C 10.1.1.0 is directly connected, Loopback1
172.16.0.0/16 is variably subnetted, 4 subnets, 3 masks
D 172.16.0.0/16 is a summary, 00:00:52, Null0
D 172.16.1.0/24 [90/40514560] via 172.16.3.1, 00:00:52, Serial0/0/0
C 172.16.2.0/24 is directly connected, FastEthernet0/0
C 172.16.3.0/30 is directly connected, Serial0/0/0
D 192.168.1.0/24 [90/3014400] via 192.168.10.10, 00:00:11, Serial0/0/1
192.168.10.0/24 is variably subnetted, 3 subnets, 2 masks
D 192.168.10.0/24 is a summary, 00:00:11, Null0
D 192.168.10.4/30 [90/3523840] via 192.168.10.10, 00:00:11,
Serial0/0/1
C 192.168.10.8/30 is directly connected, Serial0/0/1
What is the feasible distance to the 192.168.1.0 network?
3014400
Would R2 consider R1 to be a feasible successor to the 192.168.1.0 network?
yes
