1. © Wiley Inc. 2006. All Rights Reserved. CCNA: Cisco Certified Network Associate Study Guide CHAPTER 5: IP Routing

2. © Wiley Inc. 2006. All Rights Reserved. The CCNA exam topics covered in this chapter include the following:

3. © Wiley Inc. 2006. All Rights Reserved. To route a router need to know: –Remote Networks –Neighbor Routers –All Possible routes to remote network –The absolute best route to all remote networks –Maintain and verify the routing information What is Routing? CB A D

4. © Wiley Inc. 2006. All Rights Reserved. Basic Path Selection What interface will the router send out a packet if it has destination address of 10.10.10.18?

5. © Wiley Inc. 2006. All Rights Reserved. Simple IP Routing 172.16.1.0 B A 172.16.2.0 172.16.2.2 172.16.1.2 172.16.2.1 172.16.1.1 e0 >ping 172.16.1.2 B 172.16.3.1 172.16.3.2 s0 Host A Host B

6. © Wiley Inc. 2006. All Rights Reserved. Routing/PDU Example: Host A Web browses to the HTTP Server…. 3. The destination port number in a segment header will have a value of __ 1. The destination address of a frame will be the _______________________ 2. The destination IP address of a packet will be the IP address of the ________________________________

7. © Wiley Inc. 2006. All Rights Reserved. 172.16.3.2 SO Static Routes 172.16.1.0 B 172.16.3.1 A B Stub Network 172.16.2.0 SO A Routes must be unidirectional

8. © Wiley Inc. 2006. All Rights Reserved. ip route remote network [mask] {address|interface} [distance] [permanent] Router(config)#ip route remote_network mask next_hop Static Route Configuration

9. © Wiley Inc. 2006. All Rights Reserved. ip route 172.16.1.0 255.255.255.0 172.16.3.2 or ip route 172.16.1.0 255.255.255.0 s0 Static Route Example 172.16.3.2 SO 172.16.1.0 B 172.16.3.1 A B Stub Network 172.16.2.0 SO

10. © Wiley Inc. 2006. All Rights Reserved. Default Routes 172.16.3.2 SO 172.16.1.0 B 172.16.3.1 A B Stub Network 172.16.2.0 SO ip route 0.0.0.0 0.0.0.0 172.16.3.1 ip classless

11. © Wiley Inc. 2006. All Rights Reserved. Routing protocols are used between routers to: –Determine the path of a packet through a network –Maintain routing tables –Examples? Routed protocols are: –Assigned to an interface –Once the path is determined by the Routing protocol, determines method of delivery –Examples? Routing vs. Routed

12. © Wiley Inc. 2006. All Rights Reserved. Autonomous System 1Autonomous System 2 IGPs: RIP, IGRP EGPs: BGP Routing Protocols An autonomous system is a collection of networks under a common administrative domain. IGPs operate within an autonomous system. EGPs connect different autonomous systems.

13. © Wiley Inc. 2006. All Rights Reserved. Classful Routing Overview Classful routing protocols do not include the subnet mask with the route advertisement. –Within the same network, consistency of the subnet masks is assumed. –Summary routes are exchanged between foreign networks. –Examples of classful routing protocols: RIP Version 1 (RIPv1) IGRP

14. © Wiley Inc. 2006. All Rights Reserved. Classless Routing Overview Classless routing protocols include the subnet mask with the route advertisement. –Classless routing protocols support variable-length subnet masking (VLSM). –Summary routes can be manually controlled within the network. –Examples of classless routing protocols: RIP Version 2 (RIPv2) EIGRP OSPF IS-IS

15. © Wiley Inc. 2006. All Rights Reserved. IGRP Administrative Distance=100 Router D Router B Router A Router C RIP Administrative Distance=120 Default Administrative Distance Directly Connected: 0 Static Route: 1 RIP: 120 IGRP: 100 EIGRP: 90 OSPF: 110 Administrative Distance

16. © Wiley Inc. 2006. All Rights Reserved. CB A D Routing Table Routing Table Routing Table Routing Table Routing Table Routing Table Routing Table Routing Table Distance—How far Vector—In which direction Distance vector algorithms do not allow a router to know the exact topology of an internetwork. All routers just broadcast their entire routing table out all active interfaces on periodic time intervals Distance Vector

17. © Wiley Inc. 2006. All Rights Reserved. Discovering Routes

18. © Wiley Inc. 2006. All Rights Reserved. Discovering Routes

19. © Wiley Inc. 2006. All Rights Reserved. Routing Loops

20. © Wiley Inc. 2006. All Rights Reserved. Router Loops

21. © Wiley Inc. 2006. All Rights Reserved. 64kbps T1 –Hop count metric selects the path, 16 is unreachable –Full route table broadcast every 30 seconds –Load balance maximum of 6 equal cost paths (default = 4) –RIPv2 supports VLSM and Discontiguous networks RIP Overview

22. © Wiley Inc. 2006. All Rights Reserved. Router(config)#router rip Router(config-router)#network network-number* network 172.16.0.0 network 192.168.10.0 router RIP network 172.16.0.0 network 10.0.0.0 router RIP *Network is a classful network address. Every device on network uses the same subnet mask 172.16.10.0 192.168.10.0 10.3.5.0 RIP Routing Configuration

23. © Wiley Inc. 2006. All Rights Reserved. RIP Version 2 Allows the use of variable length subnet masks (VLSM) by sending subnet mask information with each route update Distance Vector – same AD, and timers. Easy configuration, just add the command “version 2” under the router rip configuration router rip network 10.0.0.0 version 2

24. © Wiley Inc. 2006. All Rights Reserved. Discontiguous Addressing Two networks of the same classful networks are separated by a different network address 192.168.10.0/24 10.1.1.0/24 192.168.10.0/24 – –RIPv1 and IGRP do not advertise subnet masks, and therefore cannot support discontiguous subnets. – –OSPF, EIGRP, and RIPv2 can advertise subnet masks, and therefore can support discontiguous subnets.

25. © Wiley Inc. 2006. All Rights Reserved. Passive Interface Maybe you don’t want to send RIP updates out your router interface connected to the Internet. Use the passive-interface command: Router(config)#router rip Router(config-router)#passive-interface serial0 This allows a router to receive route updates on an interface, but not send updates via that interface S0 Gateway Internet Updates X X

26. © Wiley Inc. 2006. All Rights Reserved. Verifying RIP Router#show ip protocols Router#show protocols Router#show ip route Router#debug ip rip Router#undebug all (un all)

27. © Wiley Inc. 2006. All Rights Reserved. IGRP Interior Gateway Routing Protocol - Cisco Proprietary Uses bandwidth and delay of the line by default to select best path Autonomous System Router D Router B Router A Router C Requires Autonomous System number for activation

28. © Wiley Inc. 2006. All Rights Reserved. IGRP vs. RIP The important IGRP characteristics are as follows: –More scalability than RIP –Fast response to network changes –Sophisticated metric –Multiple-path support

29. © Wiley Inc. 2006. All Rights Reserved. Router(config)#router igrp autonomous-system Router(config-router)#network network-number* *Network is a classful network address. Every device on network uses the same subnet mask network 172.16.0.0 network 192.168.10.0 router IGRP 10 network 172.16.0.0 network 10.0.0.0 router IGRP 10 172.16.10.0 192.168.10.0 10.3.5.0 Configuring IGRP

30. © Wiley Inc. 2006. All Rights Reserved. Verifying IGRP Router# show ip route Router# show ip protocols Router# debug ip igrp transaction Router# debug ip igrp events Router# undebug all (un all)