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Chapter 5 RIP version 1

Chapter 5 RIP version 1. CIS 82 Routing Protocols and Concepts Rick Graziani Cabrillo College graziani@cabrillo.edu Last Updated: 3/10/2009. Note. This presentation will be updated prior to March. 25, 2008

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Chapter 5 RIP version 1

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  1. Chapter 5RIP version 1 CIS 82 Routing Protocols and Concepts Rick Graziani Cabrillo College graziani@cabrillo.edu Last Updated: 3/10/2009

  2. Note • This presentation will be updated prior to March. 25, 2008 • The audio of the lecture for this presentation will be available on my web site after March. 25, 2008 • My web site is www.cabrillo.edu/~rgraziani. • For access to these PowerPoint presentations and other materials, please email me at graziani@cabrillo.edu.

  3. For further information • This presentation is an overview of what is covered in the curriculum/book. • For further explanation and details, please read the chapter/curriculum. • Book: • Routing Protocols and Concepts • By Rick Graziani and Allan Johnson • ISBN: 1-58713-206-0 • ISBN-13: 978-58713-206-3

  4. Topics • Automatic Summarization • Modified Topology B • Boundary Routers and Automatic Summarization • Processing RIP Updates • Sending RIP Updates • Advantages and Disadvantages of Automatic Summarization • Default Route and RIPv1 • Modified Topology C • Propagating the Default Route in RIPv1 • RIPv1: Distance Vector, Classful Routing Protocol • Background and Perspective • RIPv1 Characteristics and Message Format • RIP Operation • Basic RIPv1 Configuration • RIPv1 Scenario A • Enable RIP: router rip Command • Specifying Networks • Verification and Troubleshooting • Verifying RIP: show ip route • Verifying RIP: show ip protocols • Verifying RIP: debu ip rip • Passive Interfaces

  5. RIPv1 • Download Packet Tracer Topology: cis82-RIPv1-A-student.pkt

  6. RIPv1: A Distance Vector, Classful Routing Protocol Background and Perspective RIPv1 Characteristics and Message Format RIP Operation

  7. RIPv1: Distance Vector, Classful Routing Protocol • Why learn RIP? • Still in use today. • Help understand fundamental concepts and comparisons of protocols • Classful (RIPv1) vs classless (RIPv2)

  8. Background and Perspective • RIP is not a protocol “on the way out.” • In fact, an IPv6 form of RIP called RIPng (next generation) is now available..

  9. Background and Perspective • Charles Hedrick wrote RFC 1058 in 1988, in which he documented the existing protocol and specified some improvements. • RFC 1058 can be found at http://www.ietf.org/rfc/rfc1058.txt

  10. RIPv1 Characteristics and Message Format • RIP characteristics: • Distance Vector or Link State? • Distance vector routing protocol. • Metric? • Hop count • Maximum Hop count? • Greater than 15 are considered unreachable. • Routing table updates are broadcasted every…? • 30 seconds. (RIPv2 uses multicasts)

  11. RIPv1 Characteristics and Message Format

  12. RIPv1 Characteristics and Message Format

  13. IP Address Classes and Classful Routing No subnet mask • RIPv1: • Classful routing protocol. • Does not send subnet mask in update.

  14. IP Address Classes and Classful Routing Routing Table ? Network-add/mask RIP Update network-add /16 • R2 receives an RIP update with a network address. • R2 adds the network address and mask to the routing table. • A router either uses the subnet mask: (discussed later) • Local interface or • Default classful subnet mask • Because of this limitation, RIPv1 networks cannot be discontiguous, nor can they implement VLSM.

  15. Basic RIPv1 Configuration RIPv1 Scenario A Enable RIP: router rip Command Specifying Networks

  16. RIPv1 Scenario A • RIPv1 is a classful or classless routing protocol? • Classful • How many classful networks are there and of what class? • 5 Class C network addresses. • We will see that the class of the network is used by RIPv1 to determine the subnet mask.

  17. Enabling RIP: router rip Command R1# conf t Enter configuration commands, one per line. End with CNTL/Z. R1(config)# router ? bgp Border Gateway Protocol (BGP) egp Exterior Gateway Protocol (EGP) eigrp Enhanced Interior Gateway Routing Protocol (EIGRP) igrp Interior Gateway Routing Protocol (IGRP) isis ISO IS-IS iso-igrp IGRP for OSI networks mobile Mobile routes odr On Demand stub Routes ospf Open Shortest Path First (OSPF) rip Routing Information Protocol (RIP) R1(config)# router rip R1(config-router)# • What routing protocols does this router support? (PT is limited) • Configure RIP…

  18. Enabling RIP: router rip Command R1# conf t R1(config)# router rip R1(config-router)# network 192.168.1.0 R1(config-router)# network 192.168.2.0 R1(config-router)# exit R1(config)# norouter rip • no router rip • To remove the RIP routing process from a device • Stops the RIP process • Erases all existing RIP configuration commands.

  19. Specifying Networks Router(config-router)# networkdirectly-connected-classful-network-address • To enable RIP routing for a network, use the networkcommand in router configuration mode • Enter the classful network address for each directly connected network.

  20. Specifying Networks R1(config)# router rip R1(config-router)#network 192.168.1.0 R1(config-router)#network 192.168.2.0 RIP Update • The network command performs the following functions: • Enables RIP on all interfaces that belong to a specific network. • Associated interfaces will now both send and receive RIP updates. • Advertises the specified network in RIP routing updates sent to other routers every 30 seconds (no mask).

  21. Specifying Networks Only directly connected classful network addresses! R1(config)# router rip R1(config-router)# network 192.168.1.0 R1(config-router)# network 192.168.2.0 R2(config)# router rip R2(config-router)# network 192.168.2.0 R2(config-router)# network 192.168.3.0 R2(config-router)# network 192.168.4.0 R3(config)# router rip R3(config-router)# network 192.168.4.0 R3(config-router)# network 192.168.5.0 • Configure RIP for all three routers • What happens if you enter a subnet or host IP address? (Try it) • IOS automatically converts it to a classful network address. • For example, if you enter the command network 192.168.1.32, the router will convert it to network 192.168.1.0.

  22. Only directly connected classful network addresses!

  23. Administrative Distance R3# show ip route Codes: C - connected, S - static, I - IGRP, R - RIP, <some output omitted> * - candidate default, U - per-user static route, o - ODR P - periodic downloaded static route Gateway of last resort is not set R 192.168.1.0/24 [120/2] via 192.168.4.2, 00:00:13, Serial0/0/1 R 192.168.2.0/24 [120/1] via 192.168.4.2, 00:00:25, Serial0/0/1 R 192.168.3.0/24 [120/1] via 192.168.4.2, 00:00:25, Serial0/0/1 C 192.168.4.0/24 is directly connected, Serial0/0/1 C 192.168.5.0/24 is directly connected, FastEthernet0/0 R3# R = RIP • What is the administrative distance of a network route learned via RIP? • 120

  24. Administrative Distance R3# show ip protocols <output omitted> Routing Protocol is “rip” Routing Information Sources: Gateway Distance Last Update 192.168.6.2 120 00:00:10 Distance: (default is 120) • Where is the administrative distance displayed using this command?

  25. Verification and Troubleshooting Verifying RIP: show ip route Verifying RIP: show ip protocols Verifying RIP: debu ip rip Passive Interfaces

  26. Verifying RIP: show ip route on all three routers… R1# show ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, <output omitted> Gateway of last resort is not set R 192.168.4.0/24 [120/1] via 192.168.2.2, 00:00:02, Serial0/0/0 R 192.168.5.0/24 [120/2] via 192.168.2.2, 00:00:02, Serial0/0/0 C 192.168.1.0/24 is directly connected, FastEthernet0/0 C 192.168.2.0/24 is directly connected, Serial0/0/0 R 192.168.3.0/24 [120/1] via 192.168.2.2, 00:00:02, Serial0/0/0 • The routing table, includes what kind of routes? • Directly connected networks • Static routes • Dynamic routes • Why might a RIP route not be immediately displayed in the routing table? • Networks will take some time to converge.

  27. Verifying RIP: show ip route Command R2# show ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, <output omitted> Gateway of last resort is not set C 192.168.4.0/24 is directly connected, Serial0/0/1 R 192.168.5.0/24 [120/1] via 192.168.4.1, 00:00:12, Serial0/0/1 R 192.168.1.0/24 [120/1] via 192.168.2.1, 00:00:24, Serial0/0/0 C 192.168.2.0/24 is directly connected, Serial0/0/0 C 192.168.3.0/24 is directly connected, FastEthernet0/0 • Using R2, which routes do you expect to see in our scenario? • Directly connected networks of R2 • RIP routes for remote networks • What routes do you expect not to see? • Networks not in our scenario – not configured with network statements on the routers. • Static default route

  28. Verifying RIP: show ip route Command R3# show ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, <output omitted> Gateway of last resort is not set C 192.168.4.0/24 is directly connected, Serial0/0/1 C 192.168.5.0/24 is directly connected, FastEthernet0/0 R 192.168.1.0/24 [120/2] via 192.168.4.2, 00:00:08, Serial0/0/1 R 192.168.2.0/24 [120/1] via 192.168.4.2, 00:00:08, Serial0/0/1 R 192.168.3.0/24 [120/1] via 192.168.4.2, 00:00:08, Serial0/0/1

  29. Verifying RIP: show ip route Command R1# show ip route <output omitted> R 192.168.5.0/24 [120/2] via 192.168.2.2, 00:00:23, Serial0/0/0

  30. Examine and discuss the show ip protocols Command

  31. Verifying RIP: show ip protocols Command • Verifies that RIP routing is configured and running on Router R2 • At least one active interface with an associated network command is needed before RIP routing will start.

  32. Verifying RIP: show ip protocols Command • These are the timers that show when the next round of updates will be sent out from this router—23 seconds from now, in the example.

  33. Verifying RIP: show ip protocols Command • This information relates to filtering updates and redistributing routes, if configured on this router. • Filtering and redistribution are both CCNP-level topics.

  34. Verifying RIP: show ip protocols Command • Information about which RIP version is currently configured and which interfaces are participating in RIP updates.

  35. Verifying RIP: show ip protocols Command • Router R2 is currently summarizing at the classful network boundary • By default, will use up to four equal-cost routes to load-balance. • Automatic summarization is discussed later in this chapter.

  36. Verifying RIP: show ip protocols Command • Classful networks configured with the network command are listed next. • These are the networks that R2 will include in its RIP updates. (with other learned routes)

  37. Verifying RIP: show ip protocols Command • RIP neighbors • Gateway: Next-hop IP address of the neighbor that is sending R2 updates. • Distance is the AD that R2 uses for updates sent by this neighbor. • Last Update is the seconds since the last update was received from this neighbor.

  38. Use debug ip rip to view RIP updates that are sent and received… • The debug command is a useful tool to help diagnose and resolve networking problems, providing real-time, continuous information.

  39. RIP: received v1 update from 192.168.2.1 on Serial0/0/0 192.168.1.0 in 1 hops • Assuming all routers have converged, why were no other routes from R1’s routing table sent to R2? • Split horizon rule. • R1 is will not advertise networks back to R2 that were learned from R2.

  40. RIP: received v1 update from 192.168.4.1 on Serial0/0/1 192.168.5.0 in 1 hops

  41. RIP: sending v1 update to 255.255.255.255 via FastEthernet0/0 (192.168.3.1) RIP: build update entries network 192.168.1.0 metric 2 network 192.168.2.0 metric 1 network 192.168.4.0 metric 1 network 192.168.5.0 metric 2 Learned via RIP from R1 Learned via RIP from R3 Directly Connected

  42. RIP: sending v1 update to 255.255.255.255 via Serial0/0/1 (192.168.4.2) RIP: build update entries network 192.168.1.0 metric 2 network 192.168.2.0 metric 1 network 192.168.3.0 metric 1 Directly Connected Learned via RIP from R1

  43. RIP: sending v1 update to 255.255.255.255 via Serial0/0/0 (192.168.2.2) RIP: build update entries network 192.168.3.0 metric 1 network 192.168.4.0 metric 1 network 192.168.5.0 metric 2 R2# undebug all All possible debugging has been turned off Directly Connected Learned via RIP from R3

  44. Passive Interfaces Got Router? • Does R2 need to send RIP updates out Fa 0/0? What are the disadvantages to this? • No, there is no RIP router or any router. • Bandwidth is wasted transporting unnecessary updates. • All devices on the LAN must process the RIPv1 update up to the transport layer. • Security risk (Authentication would is a better solution - later)

  45. Passive Interfaces Router(config-router)# passive-interface interface-type interface-number • What about using on R2: R2(Config-router)# no network 192.168.3.0 • R2 would not advertise this LAN as a route in updates sent to R1 and R3. • Correct solution is to use the passive-interfacecommand

  46. Passive Interfaces – Use it on R2… R2(config)# router rip R2(config-router)# passive-interface FastEthernet 0/0 X

  47. Passive Interfaces R2# show ip protocols <output omitted> Interface Send Recv Triggered RIP Key-chain Serial0/0/0 1 1 2 Serial0/0/1 1 1 2 Automatic network summarization is in effect Routing for Networks: 192.168.2.0 192.168.3.0 192.168.4.0 Passive Interface(s): FastEthernet0/0 Routing Information Sources: Gateway Distance Last Update 192.168.2.1 120 00:00:27 192.168.4.1 120 00:00:23 Distance: (default is 120) FastEthernet 0/0 no longer included LAN network still included in RIP updates that are sent FastEthernet 0/0 is a passive interface

  48. Automatic Summarization Modified Topology B Boundary Routers and Automatic Summarization Processing RIP Updates Sending RIP Updates Advantages and Disadvantages of Automatic Summarization

  49. Modified Topology: Scenario B 192.168.4.0/24 172.30.0.0/16 192.168.5.0/24 • Where is the separation of classful networks? • Summarizing several routes into a single route is known as route summarizationor route aggregation. • Fewer routes = smaller routing tables = faster lookups • Some routing protocols, such as RIP, automatically summarize routes on certain routers.

  50. Modified Topology: Scenario B 192.168.4.0/24 172.30.0.0/16 192.168.5.0/24 • What are the classful networks? • 172.30.0.0/16 • 192.168.4.0/24 • 192.168.5.0/24 • How is 172.30.0.0/16 network subnetted? • 172.30.1.0/24 • 172.30.2.0/24 • 172.30.3.0/24 • Is 192.168.4.0/24 subnetted? • 192.168.4.8/30.

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