Extended experiment of EIGRP

Objective: After the experimental evidence, EIGRP to a certain purpose network segment after the subsequent disconnection, will not directly use the feasible successor route?

Modifying the Weight,metric calculation uses only the delay, as shown above. The delay of modifying the R5 L0 interface at the same time is 1000 us

R1#show IP route

Gateway of last resort are not set

5.0.0.0/24 is subnetted, 1 subnets

D 5.5.5.0 [90/7680] via 12.1.1.2, 00:02:40, serial0/0

R1#show IP eigrp topology

P 5.5.5.0/24, 1 successors, FD is 7680

Via 12.1.1.2 (7680/5120), serial0/0

Via 13.1.1.3 (10496/4864), SERIAL0/1

R1#show IP eigrp topology all-links

IP-EIGRP topology Table for AS (a)/id (14.1.1.1)

P 5.5.5.0/24, 1 successors, FD is 7680, Serno 29

Via 12.1.1.2 (7680/5120), serial0/0

Via 14.1.1.4 (7936/7680), SERIAL0/2

Via 13.1.1.3 (10496/4864), SERIAL0/1

From the output of the information can be seen, R1 to the network 5.5.5.0, go by R2, metric value is 7680. There is only one viable successor, the R3,R3 to 5.5.5.0, the distance is 4864.

Now, if R1 and R2 line is broken, then, ask R1 to R5 will take which path, is from R4 or from R3.

Via 14.1.1.4 (7936/7680), SERIAL0/2

Via 13.1.1.3 (10496/4864), SERIAL0/1

Disconnect R2. And then show

R1#show IP route

5.0.0.0/24 is subnetted, 1 subnets

D 5.5.5.0 [90/7936] via 14.1.1.4, 00:00:07, SERIAL0/2

R1#show IP eigrp topology

P 5.5.5.0/24, 1 successors, FD is 7936

Via 14.1.1.4 (7936/7680), SERIAL0/2

Via 13.1.1.3 (10496/4864), SERIAL0/1

From R3, because R3 is a viable successor. Automatically switch when R2 is unavailable.

Since the R4, the FD from R4 to 5.5.5.0 is 7936, less than 10496.

Experimental results show that from R4. But why not choose R3?

Cause: The straight connector state has changed, so it will cause R1 to re-evaluate a viable successor router for a route.

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