1 © 2004, Cisco Systems, Inc. All rights reserved. CCNA 2 v3.1 Module 7 Distance Vector Routing Protocols

222 © 2004, Cisco Systems, Inc. All rights reserved. Objectives

333 © 2004, Cisco Systems, Inc. All rights reserved. Distance Vector Updates

444 © 2004, Cisco Systems, Inc. All rights reserved. Problem: Routing Loops Routing loops can occur when inconsistent routing tables are not updated due to slow convergence in a changing network.

555 © 2004, Cisco Systems, Inc. All rights reserved. Problem: Counting to Infinity

666 © 2004, Cisco Systems, Inc. All rights reserved. Solution: Defining a Maximum for Infinity

777 © 2004, Cisco Systems, Inc. All rights reserved. Solution: Split Horizon

888 © 2004, Cisco Systems, Inc. All rights reserved. Solution: Route Poisoning

999 © 2004, Cisco Systems, Inc. All rights reserved. Solution: Triggered Updates

10 © 2004, Cisco Systems, Inc. All rights reserved. Solution: Holddown Timers

11 © 2004, Cisco Systems, Inc. All rights reserved. Key Characteristics of RIP

12 © 2004, Cisco Systems, Inc. All rights reserved. RIP Commands Using router rip and network commands to Enable RIP Enabling RIP on an IP-addressed network Monitoring IP packet flow using the show ip protocol command The show ip route command

13 © 2004, Cisco Systems, Inc. All rights reserved. Configuring RIP

14 © 2004, Cisco Systems, Inc. All rights reserved. Using the ip classless Command

15 © 2004, Cisco Systems, Inc. All rights reserved. RIP Configuration Issues To reduce routing loops and counting to infinity, RIP uses the following: Defining infinity Split horizon Route poisoning & poison reverse Triggered updates Holddown timers

16 © 2004, Cisco Systems, Inc. All rights reserved. The show ip protocols Command

17 © 2004, Cisco Systems, Inc. All rights reserved. The show ip route Command

18 © 2004, Cisco Systems, Inc. All rights reserved. Troubleshooting RIP Update Issues debug ip rip show ip rip database show ip protocols {summary} show ip route debug ip rip {events} show ip interface brief

19 © 2004, Cisco Systems, Inc. All rights reserved. Preventing Routing Updates through an Interface

20 © 2004, Cisco Systems, Inc. All rights reserved. Load Balancing with RIP

21 © 2004, Cisco Systems, Inc. All rights reserved. Administrative Distance

22 © 2004, Cisco Systems, Inc. All rights reserved. Integrating Static Route with RIP A router running RIP can receive a default route via an update from another router running RIP. Another option is for the router to generate the default route itself. The administrator can override a static route with dynamic routing information by adjusting the administrative distance values.

23 © 2004, Cisco Systems, Inc. All rights reserved. IGRP Features

24 © 2004, Cisco Systems, Inc. All rights reserved. IGRP Commands Using router igrp and network commands to enable IGRP Enabling IGRP on an IP-addressed network Monitoring IP packet flow using the show ip protocol command The show ip interfaces command The show ip route command The debug ip rip command

25 © 2004, Cisco Systems, Inc. All rights reserved. IGRP Metrics Bandwidth – The lowest bandwidth value in the path Delay – The cumulative interface delay along the path Reliability – The reliability on the link towards the destination as determined by the exchange of keepalives Load – The load on a link towards the destination based on bits per second

26 © 2004, Cisco Systems, Inc. All rights reserved. IGRP Routes: Interior, System, & Exterior

27 © 2004, Cisco Systems, Inc. All rights reserved. IGRP Stability Features Holddowns, Split horizons, & Poison-reverse updates

28 © 2004, Cisco Systems, Inc. All rights reserved. Configuring IGRP

29 © 2004, Cisco Systems, Inc. All rights reserved. Migrating RIP to IGRP 1.Verify existing routing protocol (RIP) on the routers to be converted. 2.Configure IGRP on RouterA and RouterB 3.Enter show ip protocols on RouterA and RouterB 4.Enter show ip route on RouterA and RouterB

30 © 2004, Cisco Systems, Inc. All rights reserved. Migrating RIP to IGRP

31 © 2004, Cisco Systems, Inc. All rights reserved. Verifying IGRP Configuration Some commands for checking IGRP configuration are as follows: show interface interface show running-config show running-config interface interface show running-config | begin interface interface show running-config | begin igrp show ip protocols

32 © 2004, Cisco Systems, Inc. All rights reserved. Troubleshooting IGRP The following commands are useful when troubleshooting IGRP: show ip protocols {summary} show ip route debug ip igrp events IGRP protocol events debug ip igrp transactions IGRP protocol transactions ping traceroute

33 © 2004, Cisco Systems, Inc. All rights reserved. Summary