1 © 2003, Cisco Systems, Inc. All rights reserved. CCNA 3 v3.0 Module 3 EIGRP

222 © 2003, Cisco Systems, Inc. All rights reserved. Objectives EIGRP concepts EIGRP configuration Troubleshooting Routing protocols

333 © 2003, Cisco Systems, Inc. All rights reserved. Comparing EIGRP with IGRP Comparisons between EIGRP and IGRP fall into the following major categories: Compatibility mode Metric calculation Hop count Automatic protocol redistribution Route tagging

444 © 2003, Cisco Systems, Inc. All rights reserved. Using EIGRP with IGRP

555 © 2003, Cisco Systems, Inc. All rights reserved. EIGRP Concepts Every EIGRP router maintains a topology table for each configured network protocol. All learned routes to a destination are maintained in the topology table.

666 © 2003, Cisco Systems, Inc. All rights reserved. EIGRP Successors and Feasible Successors

777 © 2003, Cisco Systems, Inc. All rights reserved. EIGRP Design Features

888 © 2003, Cisco Systems, Inc. All rights reserved. EIGRP Technologies Neighbor discovery and recovery Reliable Transport Protocol DUAL finite-state machine algorithm Protocol-dependent modules By forming adjacencies, EIGRP routers: Dynamically learn of new routes that join their network Identify routers that become either unreachable or inoperable Rediscover routers that had previously been unreachable

999 © 2003, Cisco Systems, Inc. All rights reserved. Data Structure The five EIGRP packet types are as follows: Hello (used to discover, verify, and rediscover neighbor routers) Acknowledgment Update Query Reply

10 © 2003, Cisco Systems, Inc. All rights reserved. Default Hello Intervals and Hold Times for EIGRP

11 © 2003, Cisco Systems, Inc. All rights reserved. Feasible Successor Route Selection Rules

12 © 2003, Cisco Systems, Inc. All rights reserved. Configuring EIGRP

13 © 2003, Cisco Systems, Inc. All rights reserved. EIGRP Automatically Summarizes Based on Class

14 © 2003, Cisco Systems, Inc. All rights reserved. Manual Summarization with EIGRP

15 © 2003, Cisco Systems, Inc. All rights reserved. Verifying EIGRP

16 © 2003, Cisco Systems, Inc. All rights reserved. EIGRP debug Commands

17 © 2003, Cisco Systems, Inc. All rights reserved. Building Neighbor Tables

18 © 2003, Cisco Systems, Inc. All rights reserved. Discover Routes

19 © 2003, Cisco Systems, Inc. All rights reserved. Select Routes If a link goes down, DUAL looks for an alternative route path, or feasible successor, in the topology table. If a feasible successor is not found, the route is flagged as Active, or unusable at present. Query packets are sent to neighboring routers requesting topology information. DUAL uses this information to recalculate successor and feasible successor routes to the destination.

20 © 2003, Cisco Systems, Inc. All rights reserved. Troubleshooting Process 1.Analyze the network failure, make a clear problem statement. 2.Gather the facts needed to help isolate possible causes. 3.Consider possible problems based on the facts that have been gathered. 4.Create an action plan based on the remaining potential problems. 5.Implement the action plan, performing each step carefully while testing to see whether the symptom disappears. 6.Analyze the results to determine whether the problem has been resolved. If it has, the process is complete. 7.If the problem has not been resolved, create an action plan based on the next most likely problem in the list. Return to Step 4, change one variable at a time, and repeat the process until the problem is solved. 8.Once the actual cause of the problem is identified, try to solve it.

21 © 2003, Cisco Systems, Inc. All rights reserved. Troubleshooting RIP Configuration Layer 1 or Layer 2 connectivity issues exist. VLSM subnetting is configured. VLSM subnetting cannot be used with RIPv1 Mismatched RIPv1 and RIPv2 routing configurations exist. Network statements are missing or incorrectly assigned. The outgoing interface is down. The advertised network interface is down.

22 © 2003, Cisco Systems, Inc. All rights reserved. Troubleshooting IGRP Configuration

23 © 2003, Cisco Systems, Inc. All rights reserved. Troubleshooting EIGRP Configuration

24 © 2003, Cisco Systems, Inc. All rights reserved. Troubleshooting EIGRP Configuration

25 © 2003, Cisco Systems, Inc. All rights reserved. Troubleshooting OSPF Configuration