1. Chapter 7 RIP version 2 CIS 82 Routing Protocols and Concepts Rick Graziani Cabrillo College graziani@cabrillo.edu Last Updated: 4/7/2008

2. 2 Note 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. 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. 4 Topics RIPv1 Limitations  RIPv1: Topology Limitations  RIPv1: Discontiguous Networks  RIPv1: No VLSM Support  RIPv1: No CIDR Support Configuring RIPv2  Enabling and Verifying RIPv2  Auto-Summary and RIPv2  Disabling Auto-Summary in RIPv2  Verifying RIPv2 Updates VLSM and CIDR  RIPv2 and VLSM  RIPv2 and CIDR Verifying and Troubleshooting RIPv2  Verification and Troubleshooting Commands  Common RIPv2 Issues  Authentication

5. RIPv1 Limitations RIPv1: Topology Limitations RIPv1: Discontiguous Networks RIPv1: No VLSM Support RIPv1: No CIDR Support

6. 6 Note on Classful Routing Protocols, RIPv1 limitations The first part of this presentation discusses the limitations of classful routing protocols such as RIPv1. RIPv1 is used as an example, so we can see how RIPv2 a classless routing protocol does not have these same limitations. Classful routing protocols have three major limitations:  Does not support discontiguous networks.  Does not support VLSM  Does not support CIDR Instead of just “memorizing” these facts, we will demonstrate and “understand” why a classful routing protocol has these limitations.

7. 7 RIPv1: Distance Vector, Classess Routing Protocol RIP Version 2 (RIPv2) is defined in RFC 1723. RIPv2 is the first classless routing protocol discussed in this book. RIPv2 has lost popularity when compared to other routing protocols such as EIGRP, OSPF and IS-IS. RIPv2, it is ideal for explaining the differences between a classful routing protocol (RIPv1) and a classless routing protocol (RIPv2).

8. 8 RIPv1 and RIPv2 RIPv2 is actually an enhancement of RIPv1’s features and extensions rather than an entirely new protocol.  Next-hop addresses included in the routing updates  Use of multicast addresses in sending updates  Authentication option available Both versions of RIP share the following features and limitations:  Use of hold-down and other timers to help prevent routing loops  Use of split horizon and split horizon with poison reverse to also help prevent routing loops  Use of triggered updates when there is a change in the topology for faster convergence  Maximum hop count of 15 hops, with the hop count of 16 signifying an unreachable network

9. 9 In a discontiguous network, a classful major network address, such as 172.30.0.0/16, is separated by one or more other major networks. 172.30.0.0/16 is divided by the networks:  209.165.200.228/30  209.165.200.232/30 Classful routing protocols do not include enough routing information to route properly for discontiguous networks. RIPv1 Limitations 172.30.0.0 /16

10. 10 R2: static summary route to the 192.168.0.0/16 network.  Redistribution - Inject static route(s) into routing protocol updates. For now, this summary route will cause problems with RIPv1 because:  192.168.0.0/16 is not a major classful address (192.168.0.0/24)  Includes all the /24 versions of 192.168.0.0/16 Summary Route 172.30.0.0/16 R2(config)# ip route 192.168.0.0 255.255.0.0 null0

11. 11 R1 and R3 contain VLSM networks. Both R1 and R3 are configured with /24 subnets of the 172.30.0.0/16 network. R3: 172.30.200.0/24 subnetted again, using the first 4 bits for subnets and the last 4 for hosts.  172.30.200.16/28 and 172.30.200.32/28 VLSM 172.30.0.0/16

12. 12 VLSM R3: 172.30.200.0/24 subnetted again, using the first 4 bits for subnets and the last 4 for hosts. 172.30.200.16/28 and 172.30.200.32/28

13. 13 We use RFC 1918 and Cisco Example addresses for all topologies. Private Addresses and Cisco Example Addresses RFC 1918 Private Addresses Cisco Example Addresses

14. 14 Loopback interface  Software-only interface  Used to emulate an interface.  Can be assigned an IP address.  Specific purposes with some routing protocols such as OSPF (later) A loopback interface can be:  pinged  subnet advertised in routing updates. Ideal for simulating multiple networks attached to the same router. Loopback Interfaces 172.30.0.0/16

15. 15 RIPv1 Topology Limitations RIPv1 configuration for all three routers R1(config)# router rip R1(config-router)# network 172.30.0.0 R1(config-router)# network 209.165.200.0 R2(config)# ip route 192.168.0.0 255.255.0.0 null0 R2(config)# router rip R2(config-router)# redistribute static R2(config-router)# network 10.0.0.0 R2(config-router)# network 209.165.200.0 R3(config)# router rip R3(config-router)# network 172.30.0.0 R3(config-router)# network 209.165.200.0

16. 16 Static Routes and Null Interfaces CIDR allows route aggregation.  A single high-level route entry with a subnet mask less than the classful mask can be used to represent many lowerlevel routes. This results in fewer entries in the routing table. The static route on R2 is using a /16 mask to summarize all 256 networks ranging from 192.168.0.0/24 to 192.168.255.0/24. For Lab purposes:  The static summary route 192.168.0.0/16 does not actually exist.  To simulate this static route, we will use a null interface as the exit interface.  You do not need to enter commands to create or configure the null interface.  It is always up but does not forward or receive traffic.  Traffic sent to the null interface is discarded. R2(config)# ip route 192.168.0.0 255.255.0.0 Null0

17. 17 Route Redistribution Redistribution involves taking the routes from one routing source and sending those routes to another routing source. Routes can only be redistributed into a dynamic routing protocol.  Dynamic routing protocol to a different dynamic routing protocol.  Static routes to a dynamic routing protocol.  Directly connected networks to a dynamic routing protocol. Want R2 to redistribute our static route (192.168.0.0/16) by importing the route into RIPv1 and then sending it to R1 and R3 using the RIPv1 process. We will see whether this is indeed happening, and if not, why not. R2(config)# ip route 192.168.0.0 255.255.0.0 null0 R2(config)# router rip R2(config-router)# redistribute static Is static route being sent via RIPv1 with other RIPv1 routes?

18. 18 Verifying and Testing Connectivity Whenever R2 pings any of the 172.30.0.0 subnets on R1 or R3, only about 50 percent of the pings are successful. R2# ping 172.30.1.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.30.1.1, timeout is 2 seconds: !U!.! Success rate is 60 percent (3/5), round-trip min/avg/max = 28/29/32 ms R2# ping 172.30.100.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.30.100.1, timeout is 2 seconds: !U!.! Success rate is 60 percent (3/5), round-trip min/avg/max = 28/28/28 ms R2#

19. 19 Verifying and Testing Connectivity R1 is able to ping 10.1.0.1 but is unsuccessful when attempting to ping the 172.30.100.1 interface on R3. R1# ping 10.1.0.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.1.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5),round-trip min/avg/max = 28/28/28 ms R1# ping 172.30.100.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.30.100.1, timeout is 2 seconds:..... Success rate is 0 percent (0/5) R1# X

20. 20 Verifying and Testing Connectivity R3 is able to ping 10.1.0.1 but is unsuccessful when attempting to ping the 172.30.1.1 interface on R1. As you can see, there is an obvious problem when trying to communicate with the 172.30.0.0 discontiguous subnets. R3# ping 10.1.0.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 10.1.0.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5),round-trip min/avg/max = 28/28/28 ms R3# ping 172.30.1.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.30.1.1, timeout is 2 seconds:..... Success rate is 0 percent (0/5) R3# X

21. 21 RIPv1: Discontiguous Networks Because the subnet mask is not included in the update, RIPv1 and other classful routing protocols must summarize networks at major network boundaries.

22. 22 RIPv1 on both Routers R1 and R3 will summarize their 172.30.0.0 subnets to the classful major network address of 172.30.0.0 when sending routing updates to R2. RIPv1: Discontiguous Networks

23. 23 Examining the Routing Tables R2 has two equal-cost routes to the 172.30.0.0/16 network.  R1 and R3 are sending R2 a RIPv1 update for the 172.30.0.0 network with a metric of 1 hop. R2’s routing table only contains the major classful network address of 172.30.0.0 and adds the Class B subnet mask of /16. R2# show ip route R 172.30.0.0/16 [120/1] via 209.165.200.230, 00:00:09, Serial0/0/0 [120/1] via 209.165.200.234, 00:00:11, Serial0/0/1 209.165.200.0/30 is subnetted, 2 subnets C 209.165.200.232 is directly connected, Serial0/0/1 C 209.165.200.228 is directly connected, Serial0/0/0 10.0.0.0/16 is subnetted, 1 subnets C 10.1.0.0 is directly connected, FastEthernet0/0 S 192.168.0.0/16 is directly connected, Null0

24. 24 debug ip rip R2 is receiving two 172.30.0.0 equal-cost routes with a metric of 1 hop:  one route on Serial 0/0/0 from R1 and  the other route on Serial 0/0/1 from R3. Also notice that the subnet mask is not included with the network address in the update. R2# debug ip rip RIP: received v1 update from 209.165.200.230 on Serial0/0/0 172.30.0.0 in 1 hops RIP: received v1 update from 209.165.200.234 on Serial0/0/1 172.30.0.0 in 1 hops RIP: sending v1 update to 255.255.255.255 via Serial0/0/0 (209.165.200.229) RIP: build update entries network 10.0.0.0 metric 1 subnet 209.165.200.232 metric 1 RIP: sending v1 update to 255.255.255.255 via Serial0/0/1 (209.165.200.233) RIP: build update entries network 10.0.0.0 metric 1 subnet 209.165.200.228 metric 1

25. 25 show ip route R1 has its own 172.30.0.0 routes:  172.30.2.0/24  172.30.1.0/24. R1 does not send R2 those subnets. R1 and R3 are boundary routers only sending the summarized 172.30.0.0 Result, R2 only knows about the 172.30.0.0/16 classful network and is unaware of any 172.30.0.0 subnets. R1# show ip route 172.30.0.0/24 is subnetted, 2 subnets C 172.30.2.0 is directly connected, Loopback0 C 172.30.1.0 is directly connected, FastEthernet0/0 209.165.200.0/30 is subnetted, 2 subnets R 209.165.200.232 [120/1] via 209.165.200.229, 00:00:16,Serial0/0/0 C 209.165.200.228 is directly connected, Serial0/0/0 R 10.0.0.0/8 [120/1] via 209.165.200.229, 00:00:16, Serial0/0/0 R1#

26. 26 Determining the mask and network address Receiving an Update: Determining subnet mask for routing table  What is the major classful network address of the receiving interface?  What is the major classful network address of the network in the routing update?  Are they the same major classful network address?  Yes: Apply subnet mask of the receiving interface for this network address in the routing table.  No: Apply classful subnet mask for this network address in the routing table. Sending an Update: Determining whether or not to summarize route sent  What is the major classful network address of the sending interface?  What is the major classful network address of the network in the routing update?  Are they the same major classful network address?  Yes: Send subnet network address  No: Send summary address – the classful network address

27. 27 Example 1 172.16.0.0/1610.0.0.0/8192.168.1.0/24.1.2

28. 28 Example 1 172.16.0.0/1610.0.0.0/8192.168.1.0/24.1.2 10.0.0.0 192.168.1.0 Apply /8 classful mask Apply /24 classful mask

29. 29 Example 2 172.16.0.0/16172.17.0.0/16192.168.1.0/24.1.2

30. 30 Example 2 172.16.0.0/16172.17.0.0/16192.168.1.0/24.1.2 172.17.0.0 192.168.1.0 Apply /16 classful mask Apply /24 classful mask

31. 31 Example 3 172.16.0.0/16172.17.1.0/2410.1.1.0/24.1.2

32. 32 Example 3 172.16.0.0/24172.17.1.0/2410.1.1.0/24.1.2 172.17.0.0 (summary) 10.0.0.0 (summary) Apply /16 classful mask Apply /8 classful mask

33. 33 Example 4 172.17.2.0/24172.17.1.0/2410.1.1.0/24.1.2

34. 34 Example 4 172.17.2.0/24172.17.1.0/2410.1.1.0/24.1.2 172.17.1.0 10.0.0.0 (summary) Apply /24 interface mask Apply /8 classful mask

35. 35 Example 5 172.17.2.0/24172.17.1.0/24172.17.3.0/24.1.2

36. 36 Example 5 172.17.2.0/24172.17.1.0/24.1.2 172.17.1.0 172.17.3.0 Apply /24 interface mask 172.17.3.0/24

37. 37 Example 6 172.16.2.0/24172.17.1.0/24172.17.3.0/24.1.2

38. 38 Example 6 172.16.2.0/24172.17.1.0/24.1.2 172.17.0.0 (Summary) Apply /16 classful mask (route not used) 172.17.3.0/24

39. 39 How Classful Routing Protocols Determine Subnet Masks 172.30.0.0 Apply classful default mask of /16

40. 40 How Classful Routing Protocols Determine Subnet Masks 10.0.0.0 Apply classful default mask of /8 10.0.0.0

41. 41 How Classful Routing Protocols Determine Subnet Masks 172.30.2.0 172.30.110.0 172.30.1.0 172.30.100.0 172.30.200.16 172.30.200.32 VLSM issues: will discuss next 172.30.0.0

42. 42 RIPv1: No VLSM Support Because RIPv1 does not send the subnet mask in routing updates, it cannot support VLSM. The R3 router is configured with the following VLSM subnets, all of which are members of the Class B network 172.30.0.0/16:  172.30.100.0/24 (FastEthernet 0/0)  172.30.110.0/24 (Loopback 0)  172.30.200.16/28 (Loopback 1)  172.30.200.32/28 (Loopback 2)

43. 43 RIPv1: No VLSM Support When RIPv1 on R3 sends its 172.30.0.0 subnets out its exit interface FastEthernet 0/0, it will only include those 172.30.0.0 subnets with the same subnet mask as the exit interface. Added R4 for purposes of this discussion

44. 44 RIPv1: No CIDR Support We see the static route, let’s see if it is be sent in RIPv1 updates with the other RIPv1 routes… R2(config)# ip route 192.168.0.0 255.255.0.0 null0 R2(config)# router rip R2(config-router)# redistribute static R2(config-router)# network 10.0.0.0 R2(config-router)# network 209.165.200.0 R2(config-router)# end R2# show ip route R 172.30.0.0/16 [120/1] via 209.165.200.230, 00:00:09, Serial0/0/0 [120/1] via 209.165.200.234, 00:00:11, Serial0/0/1 209.165.200.0/30 is subnetted, 2 subnets C 209.165.200.232 is directly connected, Serial0/0/1 C 209.165.200.228 is directly connected, Serial0/0/0 10.0.0.0/16 is subnetted, 1 subnets C 10.1.0.0 is directly connected, FastEthernet0/0 S 192.168.0.0/16 is directly connected, Null0

45. 45 R1 Routing Table Notice that R1 is not receiving this 192.168.0.0/16 route in its RIP updates from R2 R1# show ip route 172.30.0.0/24 is subnetted, 2 subnets C 172.30.2.0 is directly connected, FastEthernet0/1 C 172.30.1.0 is directly connected, FastEthernet0/0 209.165.200.0/30 is subnetted, 2 subnets R 209.165.200.232 [120/1] via 209.165.200.229, 00:00:16,Serial0/0/0 C 209.165.200.228 is directly connected, Serial0/0/0 R 10.0.0.0/8 [120/1] via 209.165.200.229, 00:00:16, Serial0/0/0

46. 46 debug ip rip R2 is not including the 192.168.0.0/16 route in its RIPv1 updates to either R1 or R3. R2# debug ip rip RIP: received v1 update from 209.165.200.230 on Serial0/0/0 172.30.0.0 in 1 hops RIP: received v1 update from 209.165.200.234 on Serial0/0/1 172.30.0.0 in 1 hops RIP: sending v1 update to 255.255.255.255 via Serial0/0/0 (209.165.200.229) RIP: build update entries network 10.0.0.0 metric 1 subnet 209.165.200.232 metric 1 RIP: sending v1 update to 255.255.255.255 via Serial0/0/1 (209.165.200.233) RIP: build update entries network 10.0.0.0 metric 1 subnet 209.165.200.228 metric 1

47. 47 RIPv1: No CIDR Support The static route 192.168.0.0 has a /16 mask. This is fewer bits than the classful Class C mask of /24. RIPv1 and other classful routing protocols cannot support CIDR routes that are summarized routes with a smaller subnet mask than the classful mask of the route. RIPv1 ignores these supernets in the routing table and does not include them in updates to other routers. This is because the receiving router would only be able to apply the larger /24 classful mask to the update and not the shorter /16 mask. Note:  If the 192.168.0.0 static route were configured with a /24 mask or greater, this route would be included in the RIP updates.  The receiving routers would apply the classful /24 mask to this update. R2(config)# ip route 192.168.0.0 255.255.0.0 null0 R2(config)# router rip R2(config-router)# redistribute static

48. Configuring RIPv2 Enabling and Verifying RIPv2 Auto-Summary and RIPv2 Disabling Auto-Summary in RIPv2 Verifying RIPv2 Updates

49. 49 Configuring RIPv2 Configuring RIPv2 is similar to configuring RIPv1, with the addition of a single RIP command, version 2. Although RIPv2 uses the same basic configuration commands as RIPv1, the results of using RIPv2 are different, allowing both CIDR and VLSM to be used in the network.

50. 50 Enabling and Verifying RIPv2 RIPv2 is defined in RFC 1723. RIPv2 message format is the subnet mask field that allows a 32-bit mask to be included in the RIP route entry. As a result, the receiving router no longer depends on the subnet mask of the inbound interface or the classful mask when determining the subnet mask for a route.

51. 51 Enabling and Verifying RIPv2 Default RIPv1: When configuring RIP  Router only sends RIPv1 messages, it can process both RIPv1 and RIPv2 messages.  Ignore the RIPv2 fields in the route entry. RIPv2 will ignore RIPv1 updates. FYI only: The interface commands ip rip send and ip rip receive can be used to force compatibility between different versions. R2# show ip protocols Default version control: send version 1, receive any version 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

52. 52 Enabling and Verifying RIPv2 version 2 command is used to modify RIP to use Version 2. This command should be configured on all routers in the routing domain. R1(config)# router rip R1(config-router)# version 2 R2(config)# router rip R2(config-router)# version 2 R3(config)# router rip R3(config-router)# version 2

53. 53 Enabling and Verifying RIPv2 R2# show ip protocols Routing Protocol is “rip” Sending updates every 30 seconds, next due in 1 seconds Invalid after 180 seconds, hold down 180, flushed after 240 Outgoing update filter list for all interfaces is Incoming update filter list for all interfaces is Redistributing: static, rip Default version control: send version 2, receive version 2 Interface Send Recv Triggered RIP Key-chain Serial0/0/0 2 2 Serial0/0/1 2 2 Automatic network summarization is in effect

54. 54 Restoring RIP to Version 1 Default behavior of RIPv1 can be restored by using either the (slightly different behaviors in sending and receiving):  version 1 command  no version command If done, should be configured on all routers. R1(config)# router rip R1(config-router)# version 1 !or R1(config)# router rip R1(config-router)# no version

55. 55 Auto-Summary and RIPv2 You still see the summarized 172.30.0.0/16 route with the same two equal-cost paths. R2# show ip route R 172.30.0.0/16 [120/1] via 209.165.200.230, 00:00:28, Serial0/0/0 [120/1] via 209.165.200.234, 00:00:18, Serial0/0/1 209.165.200.0/30 is subnetted, 2 subnets C 209.165.200.232 is directly connected, Serial0/0/1 C 209.165.200.228 is directly connected, Serial0/0/0 10.0.0.0/16 is subnetted, 1 subnets C 10.1.0.0 is directly connected, FastEthernet0/0 S 192.168.0.0/16 is directly connected, Null0

56. 56 Auto-Summary and RIPv2 Routers R1 and R3 still do not include the 172.30.0.0 subnets of the other router. The only difference so far between RIPv1 and RIPV2 is that R1 and R3 each have a route to 192.168.0.0/16. This route was the (CIDR) static route configured on R2 and redistributed by RIP. What’s happening? R1# show ip route 172.30.0.0/24 is subnetted, 2 subnets C 172.30.2.0 is directly connected, Loopback0 C 172.30.1.0 is directly connected, FastEthernet0/0 209.165.200.0/30 is subnetted, 2 subnets R 209.165.200.232 [120/1] via 209.165.200.229, 00:00:04,Serial0/0/0 C 209.165.200.228 is directly connected, Serial0/0/0 R 10.0.0.0/8 [120/1] via 209.165.200.229, 00:00:04, Serial0/0/0 R 192.168.0.0/16 [120/1] via 209.165.200.229, 00:00:04, Serial0/0/0

57. 57 Auto-Summary and RIPv2 Notice that RIPv2 is sending both the network address and subnet mask. Notice that the route sent is the summarized classful network address, 172.30.0.0/16  not the individual 172.30.1.0/24 and 172.30.2.0/24 subnets. R1# debug ip rip RIP: sending v2 update to 224.0.0.9 via Serial0/0/0 (209.165.200.230) RIP: build update entries 172.30.0.0/16 via 0.0.0.0, metric 1, tag 0 RIP: received v2 update from 209.165.200.229 on Serial0/0/0 10.0.0.0/8 via 0.0.0.0 in 1 hops 192.168.0.0/16 via 0.0.0.0 in 1 hops 209.165.200.232/30 via 0.0.0.0 in 1 hops

58. 58 Auto-Summary and RIPv2 By default, RIPv2 automatically summarizes networks at major network boundaries, just like RIPv1. Both R1 and R3 routers are still summarizing their 172.30.0.0 subnets to the Class B address of 172.30.0.0 when sending updates out their interfaces on the 209.165.200.228 and 209.165.200.232 networks, respectively. R1# show ip protocols Routing Protocol is “rip” Default version control: send version 2, receive version 2 Interface Send Recv Triggered RIP Key-chain FastEthernet0/0 2 2 FastEthernet0/1 2 2 Serial0/1/0 2 2 Automatic network summarization is in effect

59. 59 Disabling Auto-summary in RIPv2 To modify the default RIPv2 behavior of automatic summarization, use the no auto-summary command R2(config)# router rip R2(config-router)# no auto-summary R3(config)# router rip R3(config-router)# no auto-summary R1(config)# router rip R1(config-router)# no auto-summary R1# show ip protocols Automatic network summarization is not in effect

60. 60 Verifying RIPv2 Updates The routing table for R2 now contains the individual subnets for 172.30.0.0/16. Notice that a single summary route with two equal-cost paths no longer exists. Each subnet and mask has its own specific entry, along with the exit interface and next-hop address to reach that subnet. R2# show ip route 172.30.0.0/16 is variably subnetted, 6 subnets, 2 masks R 172.30.200.32/28 [120/1] via 209.165.200.234, 00:00:09, Serial0/0/1 R 172.30.200.16/28 [120/1] via 209.165.200.234, 00:00:09, Serial0/0/1 R 172.30.2.0/24 [120/1] via 209.165.200.230, 00:00:03, Serial0/0/0 R 172.30.1.0/24 [120/1] via 209.165.200.230, 00:00:03, Serial0/0/0 R 172.30.100.0/24 [120/1] via 209.165.200.234, 00:00:09, Serial0/0/1 R 172.30.110.0/24 [120/1] via 209.165.200.234, 00:00:09, Serial0/0/1 209.165.200.0/30 is subnetted, 2 subnets C 209.165.200.232 is directly connected, Serial0/0/1 C 209.165.200.228 is directly connected, Serial0/0/0 10.0.0.0/16 is subnetted, 1 subnets C 10.1.0.0 is directly connected, FastEthernet0/0 S 192.168.0.0/16 is directly connected, Null0

61. 61 Verifying RIPv2 Updates Fully converged routing tables. R1# show ip route 172.30.0.0/16 is variably subnetted, 6 subnets, 2 masks R 172.30.200.32/28 [120/2] via 209.165.200.229, 00:00:01, Serial0/0/0 R 172.30.200.16/28 [120/2] via 209.165.200.229, 00:00:01, Serial0/0/0 C 172.30.2.0/24 is directly connected, Loopback0 C 172.30.1.0/24 is directly connected, FastEthernet0/0 R 172.30.100.0/24 [120/2] via 209.165.200.229, 00:00:01, Serial0/0/0 R 172.30.110.0/24 [120/2] via 209.165.200.229, 00:00:01, Serial0/0/0 209.165.200.0/30 is subnetted, 2 subnets R 209.165.200.232 [120/1] via 209.165.200.229, 00:00:02, Serial0/0/0 C 209.165.200.228 is directly connected, Serial0/0/0 10.0.0.0/16 is subnetted, 1 subnets R 10.1.0.0 [120/1] via 209.165.200.229, 00:00:02, Serial0/0/0 R 192.168.0.0/16 [120/1] via 209.165.200.229, 00:00:02, Serial0/0/0

62. 62 Verifying RIPv2 Updates Fully converged routing tables. R3# show ip route 172.30.0.0/16 is variably subnetted, 6 subnets, 2 masks C 172.30.200.32/28 is directly connected, Loopback2 C 172.30.200.16/28 is directly connected, Loopback1 R 172.30.2.0/24 [120/2] via 209.165.200.233, 00:00:01, Serial0/0/1 R 172.30.1.0/24 [120/2] via 209.165.200.233, 00:00:01, Serial0/0/1 C 172.30.100.0/24 is directly connected, FastEthernet0/0 C 172.30.110.0/24 is directly connected, Loopback0 209.165.200.0/30 is subnetted, 2 subnets C 209.165.200.232 is directly connected, Serial0/0/1 R 209.165.200.228 [120/1] via 209.165.200.233, 00:00:02, Serial0/0/1 10.0.0.0/16 is subnetted, 1 subnets R 10.1.0.0 [120/1] via 209.165.200.233, 00:00:02, Serial0/0/1 R 192.168.0.0/16 [120/1] via 209.165.200.233, 00:00:02, Serial0/0/1

63. 63 Verifying RIPv2 Updates R2# debug ip rip RIP: received v2 update from 209.165.200.234 on Serial0/0/1 172.30.100.0/24 via 0.0.0.0 in 1 hops 172.30.110.0/24 via 0.0.0.0 in 1 hops 172.30.200.16/28 via 0.0.0.0 in 1 hops 172.30.200.32/28 via 0.0.0.0 in 1 hops RIP: sending v2 update to 224.0.0.9 via Serial0/0/0 (209.165.200.229) RIP: build update entries 10.1.0.0/16 via 0.0.0.0, metric 1, tag 0 172.30.100.0/24 via 0.0.0.0, metric 2, tag 0 172.30.110.0/24 via 0.0.0.0, metric 2, tag 0 172.30.200.16/28 via 0.0.0.0, metric 2, tag 0 172.30.200.32/28 via 0.0.0.0, metric 2, tag 0 192.168.0.0/16 via 0.0.0.0, metric 1, tag 0 209.165.200.232/30 via 0.0.0.0, metric 1, tag 0 Sending and receiving routing updates, which are individual routes with their subnet mask instead of a single summary route with the classful mask.

64. 64 Verifying RIPv2 Updates Notice also that the updates are sent using the multicast address 224.0.0.9. RIPv1 sends updates as a broadcast 255.255.255.255. In general multicast updates:  Take up less bandwidth on the network.  Require less processing by devices that are not RIP enabled. R2# debug ip rip RIP: sending v2 update to 224.0.0.9 via Serial0/0/0 (209.165.200.229)

65. VLSM and CIDR RIPv2 and VLSM RIPv2 and CIDR

66. 66 RIPv2 and VLSM With RIPv2, R3 can now include all the 172.30.0.0 subnets in its routing updates to R4 This is because RIPv2 can include the proper subnet mask with the network address in the update. Added R4 for purposes of this discussion

67. 67 RIPv2 and VLSM R3# debug ip rip RIP: sending v2 update to 224.0.0.9 via FastEthernet0/0 (172.30.100.1) RIP: build update entries 10.1.0.0/16 via 0.0.0.0, metric 2, tag 0 172.30.1.0/24 via 0.0.0.0, metric 3, tag 0 172.30.2.0/24 via 0.0.0.0, metric 3, tag 0 172.30.110.0/24 via 0.0.0.0, metric 1, tag 0 172.30.200.16/28 via 0.0.0.0, metric 1, tag 0 172.30.200.32/28 via 0.0.0.0, metric 1, tag 0 192.168.0.0/16 via 0.0.0.0, metric 2, tag 0 209.165.200.228/30 via 0.0.0.0, metric 2, tag 0 209.165.200.232/30 via 0.0.0.0, metric 1, tag 0

68. 68 RIPv2 and CIDR Supernets have masks that are smaller than the classful mask (/16 here, instead of the classful /24). For the supernet to be included in a routing update, the routing protocol must have the capability of carrying that mask. In other words, it must be a classless routing protocol, like RIPv2. R2(config)# ip route 192.168.0.0 255.255.0.0 Null0

69. 69 RIPv2 and CIDR CIDR supernet is included in the routing update sent by R2. Automatic summarization does not have to be disabled on RIPv2 or any classless routing protocol for supernets to be included in the updates. R2# debug ip rip RIP: sending v2 update to 224.0.0.9 via Serial0/0/0 (209.165.200.229) RIP: build update entries 10.1.0.0/16 via 0.0.0.0, metric 1, tag 0 172.30.100.0/24 via 0.0.0.0, metric 2, tag 0 172.30.110.0/24 via 0.0.0.0, metric 2, tag 0 172.30.200.16/28 via 0.0.0.0, metric 2, tag 0 172.30.200.32/28 via 0.0.0.0, metric 2, tag 0 192.168.0.0/16 via 0.0.0.0, metric 1, tag 0 209.165.200.232/30 via 0.0.0.0, metric 1, tag 0

70. 70 RIPv2 and CIDR The routing table for R1 shows that it has received the supernet route from R2. R1 applies the subnet mask that was sent in the routing update. R1# show ip route 172.30.0.0/16 is variably subnetted, 6 subnets, 2 masks R 172.30.200.32/28 [120/2] via 209.165.200.229, 00:00:01, Serial0/0/0 R 172.30.200.16/28 [120/2] via 209.165.200.229, 00:00:01, Serial0/0/0 C 172.30.2.0/24 is directly connected, Loopback0 C 172.30.1.0/24 is directly connected, FastEthernet0/0 R 172.30.100.0/24 [120/2] via 209.165.200.229, 00:00:01, Serial0/0/0 R 172.30.110.0/24 [120/2] via 209.165.200.229, 00:00:01, Serial0/0/0 209.165.200.0/30 is subnetted, 2 subnets R 209.165.200.232 [120/1] via 209.165.200.229, 00:00:02, Serial0/0/0 C 209.165.200.228 is directly connected, Serial0/0/0 10.0.0.0/16 is subnetted, 1 subnets R 10.1.0.0 [120/1] via 209.165.200.229, 00:00:02, Serial0/0/0 R 192.168.0.0/16 [120/1] via 209.165.200.229, 00:00:02, Serial0/0/0

71. Verifying and Troubleshooting RIPv2 Verification and Troubleshooting Commands Common RIPv2 Issues Authentication

72. 72 show ip route Command First command to use to check for network convergence. Important to look for the routes that you expect to be in the routing table as well as for those that should not be in the routing table. R1# show ip route 172.30.0.0/16 is variably subnetted, 6 subnets, 2 masks R 172.30.200.32/28 [120/2] via 209.165.200.229, 00:00:01, Serial0/0/0 R 172.30.200.16/28 [120/2] via 209.165.200.229, 00:00:01, Serial0/0/0 C 172.30.2.0/24 is directly connected, Loopback0 C 172.30.1.0/24 is directly connected, FastEthernet0/0 R 172.30.100.0/24 [120/2] via 209.165.200.229, 00:00:01, Serial0/0/0 R 172.30.110.0/24 [120/2] via 209.165.200.229, 00:00:01, Serial0/0/0 209.165.200.0/30 is subnetted, 2 subnets R 209.165.200.232 [120/1] via 209.165.200.229, 00:00:02, Serial0/0/0 C 209.165.200.228 is directly connected, Serial0/0/0 10.0.0.0/16 is subnetted, 1 subnets R 10.1.0.0 [120/1] via 209.165.200.229, 00:00:02, Serial0/0/0 R 192.168.0.0/16 [120/1] via 209.165.200.229, 00:00:02, Serial0/0/0

73. 73 show ip interface brief Command If a network is missing from the routing table, it is often because an interface is down or incorrectly configured. The show ip interface brief command quickly verifies the status of all interfaces. R1# show ip interface brief Interface IP-Address OK? Method Status Protocol FastEthernet0/0 172.30.1.1 YES NVRAM up up FastEthernet0/1 172.30.2.1 YES NVRAM up up Serial0/0/0 209.165.200.230 YES NVRAM up up Serial0/0/1 unassigned YES NVRAM down down

74. 74 show ip protocols Command The show ip protocols command verifies several critical items, including whether RIP is enabled, the version of RIP, the status of automatic summarization, and the networks that were included in the network statements. R1# show ip protocols Routing Protocol is “rip” Sending updates every 30 seconds, next due in 29 seconds Invalid after 180 seconds, hold down 180, flushed after 240 Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Redistributing: rip Default version control: send version 2, receive version 2 Interface Send Recv Triggered RIP Key-chain FastEthernet0/0 2 2 FastEthernet0/1 2 2 Serial0/0/0 2 2 Automatic network summarization is not in effect Maximum path: 4 Routing for Networks: 172.30.0.0 209.165.200.0 Routing Information Sources: Gateway Distance Last Update 209.165.200.229 120 00:00:18 Distance: (default is 120)

75. 75 debug ip rip Command debug ip rip is an excellent command to use to examine the contents of the routing updates that are sent and received by a router. There can be times when a route is received by a router but is not added to the routing table. One reason for this could be that a static route is also configured for the same advertised network. R2# debug ip rip RIP: received v2 update from 209.165.200.234 on Serial0/0/1 172.30.100.0/24 via 0.0.0.0 in 1 hops 172.30.110.0/24 via 0.0.0.0 in 1 hops 172.30.200.16/28 via 0.0.0.0 in 1 hops 172.30.200.32/28 via 0.0.0.0 in 1 hops RIP: sending v2 update to 224.0.0.9 via Serial0/0/0 (209.165.200.229) RIP: build update entries 10.1.0.0/16 via 0.0.0.0, metric 1, tag 0 172.30.100.0/24 via 0.0.0.0, metric 2, tag 0 172.30.110.0/24 via 0.0.0.0, metric 2, tag 0 172.30.200.16/28 via 0.0.0.0, metric 2, tag 0 172.30.200.32/28 via 0.0.0.0, metric 2, tag 0 192.168.0.0/16 via 0.0.0.0, metric 1, tag 0 209.165.200.232/30 via 0.0.0.0, metric 1, tag 0

76. 76 ping Command An easy way to verify round-trip connectivity is with the ping command R2# ping 172.30.2.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.30.2.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 28/28/28 ms R2# ping 172.30.100.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 172.30.100.1, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 28/28/28 ms

77. 77 show running-config Command R1# show running-config ! hostname R1 ! interface FastEthernet0/0 ip address 172.30.1.1 255.255.255.0 ! interface FastEthernet0/1 ip address 172.30.2.1 255.255.255.0 ! interface Serial0/0/0 ip address 209.165.200.230 255.255.255.252 clock rate 64000 ! router rip version 2 network 172.30.0.0 network 209.165.200.0 no auto-summary !

78. 78 Common RIPv2 Issues Version:  Although RIPv1 and RIPv2 can be made compatible with additional commands beyond the scope of this course, RIPv1 does not support discontiguous subnets, VLSM, or CIDR supernet routes. network statements:  Another source of problems might be incorrectly configured or missing network statements configured with the network command.  Remember, the network command does two things: 1.It enables the routing protocol to send and receive updates on any local interfaces that belong to that network. 2.It includes the configured network in its routing updates to its neighboring routers.  A missing or incorrect network statement will result in missed routing updates and routing updates not being sent or received on an interface. Automatic summarization:  If there is a need or expectation for sending specific subnets and not just summarized routes, make sure that automatic summarization has been disabled with the no auto-summary command.

79. 79 Authentication It is good practice to authenticate routing information. RIPv2, EIGRP, OSPF, IS-IS, and Border Gateway Protocol (BGP) can be configured to encrypt and authenticate routing information.  Hides the content of the routing information  Routers will only accept routing information from other routers that have been configured with the same password or authentication information. Covered in CIS 83.

80. 80 Topics RIPv1 Limitations  RIPv1: Topology Limitations  RIPv1: Discontiguous Networks  RIPv1: No VLSM Support  RIPv1: No CIDR Support Configuring RIPv2  Enabling and Verifying RIPv2  Auto-Summary and RIPv2  Disabling Auto-Summary in RIPv2  Verifying RIPv2 Updates VLSM and CIDR  RIPv2 and VLSM  RIPv2 and CIDR Verifying and Troubleshooting RIPv2  Verification and Troubleshooting Commands  Common RIPv2 Issues  Authentication

81. Chapter 7 RIP version 2 CIS 82 Routing Protocols and Concepts Rick Graziani Cabrillo College graziani@cabrillo.edu Last Updated: 4/7/2008