9.4.6 Lab – Finite State Machine Answers

9.4.6 Lab – Finite State Machine Answers


Learning Objectives

Upon completion of this lab, you will be able to:

  • Examine EIGRP topology table
  • Verify EIGRP DUAL route calculation using the debug command
  • Examine EIGRP successor and feasible routes


In this lab activity, you will modify the EIGRP metric formula to cause a change in the topology. This will allow you to see how EIGRP reacts when a neighbor goes down due to unforeseen circumstances. You will use the debug command to view topology changes and how the DUAL Finite Machine determines successor and feasible successor paths.

Task 1: Verify EIGRP Configuration

Step 1 Examine the routing table of each router and verify that there is a path to every network in the topology.

Step 2 Verify that each router has two neighbors in its table.

Step 3 Document which path in the Topology table is the successor and feasible successor for each network.

Task 2: Observe the EIGRP Finite State Machine

Step 1 Turn on the debugging feature that will display DUAL FSM notifications on each router.

Step 2 Change the EIGRP metric formula on R1 to use only the K1 value.

Step 3 Based on the output from R2 and R3, the neighbor was down due to a k value mismatch.

Step 4 Document any changes in the topology table.

Step 5 Determine the difference in the routing table.

Step 6 Document changes in each router’s neighbor table.

Task 3: Observe Topology Notification Messages

Step 1 Turn off all debugging features for R1 only.

Step 2 Change the EIGRP metric formula on R1 back to the default values.

Step 3 Observe the DUAL notification message on R1.

Step 4 How did the DUAL FSM handle the change in topology when the route to R1 came back up?

Download Packet Tracer (.pka) file:

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