Chapter 7 RIP version 2 CIS 82 Routing Protocols and Concepts

Chapter 7 RIP version 2 CIS 82 Routing Protocols and Concepts
Rick Graziani Cabrillo College Spring 2010

Note My web site is www.cabrillo.edu/~rgraziani.
For access to these PowerPoint presentations and other materials, please me at Additional information can be found in the Notes section of this presentation.

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: ISBN-13:

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

Download Download: cis82-RIPv2-A-student.pkt
To do all configurations in this presentation cis82-RIPv2-A-completed.pkt Interfaces and RIPv1 already configured Configuration begins with RIPv2 We will use this file throughout this chapter.

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

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.

RIPv1: Distance Vector, Classess Routing Protocol
RIP Version 2 (RIPv2) is defined in RFC 1723. Classless routing protocol Less popular than EIGRP, OSPF and IS-IS. RIPv2 is ideal for explaining the differences between a classful routing protocol (RIPv1) and a classless routing protocol (RIPv2). RIP Version 2 (RIPv2) is defined in RFC 1723. Classless routing protocol 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).

RIPv1 and RIPv2 RIPv2 enhancements over RIPv1:
Next-hop addresses included in the routing updates 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 Use of split horizon and split horizon with poison reverse Use of triggered updates Maximum hop count of 15 hops 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

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

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

VLSM /16 /16 R1 and R3 contain VLSM networks. Both R1 and R3 are configured with /24 subnets of the /16 network. R3: /24 subnetted again, using the first 4 bits for subnets and the last 4 for hosts. /28 and /28 R1 and R3 contain: Subnets of the /16 network R3 contains VLSM networks /24 subnetted again: /28 and /28

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

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

Loopback Interfaces Loopback interface Software-only interface
R3(config)# interface Loopback0 R3(config-if)# ip address R3(config)# interface Loopback1 R3(config-if)# ip address R3(config)# interface Loopback2 R3(config-if)# ip address /16 /16 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 interface Software-only interface Used to emulate an interface Ideal for simulating multiple networks attached to the same router.

RIPv1 Configurations Configure RIPv1 for all three routers.
R1(config)# router rip R1(config-router)# network R1(config-router)# network R2(config)# ip route null0 R2(config)# router rip R2(config-router)# redistribute static R2(config-router)# network R2(config-router)# network R3(config)# router rip R3(config-router)# network R3(config-router)# network RIPv1 configuration for all three routers Configure RIPv1 for all three routers. Configure a static summary route for /16 to null0 on R2.

Static Routes and Null Interfaces
R2(config)# ip route Null0 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. Fewer entries in the routing table. Summarizes all 256 networks ranging from /24 to /24. For Lab purposes: The static summary route /16 does not actually exist. 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 /24 to /24. For Lab purposes: The static summary route /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.

Route Redistribution Is static route being sent via RIPv1 with other RIPv1 routes? R2(config)# ip route null0 R2(config)# router rip R2(config-router)# redistribute static 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. Between Dynamic routing protocol Static routes Directly connected networks Want R2 to redistribute our static route ( /16) into RIPv1. We will see whether this is indeed happening, and if not, why not. 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 ( /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.

Verifying and Testing Connectivity
What do you expect will happen? /16 /16 R2# ping Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to , timeout is 2 seconds: !U!.! Success rate is 60 percent (3/5), round-trip min/avg/max = 28/29/32 ms R2# ping Sending 5, 100-byte ICMP Echos to , timeout is 2 seconds: Success rate is 60 percent (3/5), round-trip min/avg/max = 28/28/28 ms R2# Whenever R2 pings any of the subnets on R1 or R3, only about 50 percent of the pings are successful. Whenever R2 pings any of the subnets on R1 or R3, only about 50 percent of the pings are successful.

What do you expect will happen? X R1# ping Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to , timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5),round-trip min/avg/max = 28/28/28 ms R1# ping Sending 5, 100-byte ICMP Echos to , timeout is 2 seconds: ..... Success rate is 0 percent (0/5) R1# R1 is able to ping but is unsuccessful when attempting to ping the interface on R3. R1 is able to ping but is unsuccessful when attempting to ping the interface on R3.

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

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

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

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

debug ip rip What do you expect to see?
R2# debug ip rip RIP: received v1 update from on Serial0/0/0 in 1 hops RIP: received v1 update from on Serial0/0/1 R2 is receiving two 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. Notice that the subnet mask is not included with the network address in the update.

show ip route What do you expect to see?
R1# show ip route /24 is subnetted, 2 subnets C is directly connected, Loopback0 C is directly connected, FastEthernet0/0 /30 is subnetted, 2 subnets R [120/1] via , 00:00:16,Serial0/0/0 C is directly connected, Serial0/0/0 R /8 [120/1] via , 00:00:16, Serial0/0/0 R1# R1 has its own routes: /24 /24. R1 does not send R2 those subnets. R1 and R3 are boundary routers only sending the summarized Result, R2 only knows about the /16 classful network and is unaware of any subnets. R1 has its own routes: /24 /24. R1 does not send R2 those subnets.

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? Yes: Send subnet network address No: Send summary address – the classful 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? Yes: Send subnet network address No: Send summary address – the classful network address

Example 1 – Name that subnet mask!
/8 /16 /24 .1 .1 .2 .1 Apply /8 classful mask Apply /24 classful mask

Example 2 - – Name that subnet mask!
/16 /16 /24 .1 .1 .2 .1 Apply /16 classful mask Apply /24 classful mask

/24 /24 /24 .1 .1 .2 .1 Apply /16 classful mask (summary) Apply /8 classful mask (summary)

/24 /24 /24 .1 .1 .2 .1 Apply /24 interface mask Apply /8 classful mask (summary)

/24 /24 /24 .1 .1 .2 .1 Apply /24 interface mask Apply /24 interface mask

/24 /24 /24 .1 .1 .2 .1 Apply /16 classful mask (route not used) (Summary) Apply /16 classful mask (route not used) (Summary)

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

Apply classful default mask of /8 Apply classful default mask of /8

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 /16: /24 (FastEthernet 0/0) /24 (Loopback 0) /28 (Loopback 1) /28 (Loopback 2) VLSM issues: will discuss next

RIPv1: No VLSM Support Added R4 for purposes of this discussion /24 When RIPv1 on R3 sends its subnets out its exit interface FastEthernet 0/0, it will only include those subnets with the same subnet mask as the exit interface. When RIPv1 on R3 sends its subnets out its exit interface FastEthernet 0/0, it will only include those subnets with the same subnet mask as the exit interface.

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

R1 Routing Table What do you expect to see?
R1# show ip route /24 is subnetted, 2 subnets C is directly connected, FastEthernet0/1 C is directly connected, FastEthernet0/0 /30 is subnetted, 2 subnets R [120/1] via , 00:00:16,Serial0/0/0 C is directly connected, Serial0/0/0 R /8 [120/1] via , 00:00:16, Serial0/0/0 Notice that R1 is not receiving this /16 route in its RIP updates from R2 Notice that R1 is not receiving this /16 route in its RIP updates from R2

debug ip rip What do you expect to see?
R2# debug ip rip RIP: received v1 update from on Serial0/0/0 in 1 hops RIP: received v1 update from on Serial0/0/1 RIP: sending v1 update to via Serial0/0/0 ( ) RIP: build update entries network metric 1 subnet metric 1 RIP: sending v1 update to via Serial0/0/1 ( ) subnet metric 1 R2 is not including the /16 route in its RIPv1 updates to either R1 or R3. R2 is not including the /16 route in its RIPv1 updates to either R1 or R3.

RIPv1: No CIDR Support The static route 192.168.0.0 has a /16 mask.
R2(config)# ip route null0 R2(config)# router rip R2(config-router)# redistribute static The static route 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 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. The static route 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 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.

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

Download Download: cis82-RIPv2-A-completed.pkt
Interfaces and RIPv1 already configured Configuration begin here with RIPv2 We will use this file throughout this chapter.

RIPv2 allows both CIDR and VLSM to be used in the network.
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. 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. RIPv2 allows both CIDR and VLSM to be used in the network.

Enabling and Verifying RIPv2
R2# show ip protocols <output omitted> Default version control: send version 1, receive any version Interface Send Recv Triggered RIP Key-chain Serial0/0/ Serial0/0/ Automatic network summarization is in effect <output omitted > 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. 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.

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 version 2 command is used to modify RIP to use Version 2. This command should be configured on all routers in the routing domain. version 2 command is used to modify RIP to use Version 2. This command should be configured on all routers in the routing domain.

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/ Serial0/0/ Automatic network summarization is in effect <output omitted for brevity>

Restoring RIP to Version 1
R1(config)# router rip R1(config-router)# version 1 !or R1(config-router)# no version Don’t do this! 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. 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.

Auto-Summary and RIPv2 What do you expect to see?
R2# show ip route R /16 [120/1] via , 00:00:28, Serial0/0/0 [120/1] via , 00:00:18, Serial0/0/1 /30 is subnetted, 2 subnets C is directly connected, Serial0/0/1 C is directly connected, Serial0/0/0 /16 is subnetted, 1 subnets C is directly connected, FastEthernet0/0 S /16 is directly connected, Null0 You still see the summarized /16 route with the same two equal-cost paths. You still see the summarized /16 route with the same two equal-cost paths.

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

R1# debug ip rip RIP: sending v2 update to via Serial0/0/0 ( ) RIP: build update entries /16 via , metric 1, tag 0 <output omitted for brevity> RIP: received v2 update from on Serial0/0/0 /8 via in 1 hops /16 via in 1 hops /30 via in 1 hops Notice that RIPv2 is sending both the network address and subnet mask. Notice that the route sent is the summarized classful network address, /16 not the individual /24 and /24 subnets. Notice that RIPv2 is sending both the network address and subnet mask. Notice that the route sent is the summarized classful network address, /16 Not the individual /24 and /24 subnets.

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

Disabling Auto-summary in RIPv2
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 <output omitted> Automatic network summarization is not in effect To modify the default RIPv2 behavior of automatic summarization, use the no auto-summary command To modify the default RIPv2 behavior of automatic summarization, use the no auto-summary command

Verifying RIPv2 Updates
What do you expect to see? R2# show ip route /16 is variably subnetted, 6 subnets, 2 masks R /28 [120/1] via , 00:00:09, Serial0/0/1 R /28 [120/1] via , 00:00:09, Serial0/0/1 R /24 [120/1] via , 00:00:03, Serial0/0/0 R /24 [120/1] via , 00:00:03, Serial0/0/0 R /24 [120/1] via , 00:00:09, Serial0/0/1 R /24 [120/1] via , 00:00:09, Serial0/0/1 /30 is subnetted, 2 subnets C is directly connected, Serial0/0/1 C is directly connected, Serial0/0/0 /16 is subnetted, 1 subnets C is directly connected, FastEthernet0/0 S /16 is directly connected, Null0 The routing table for R2 now contains the individual subnets for /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. The routing table for R2 now contains the individual subnets for /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.

R1# show ip route /16 is variably subnetted, 6 subnets, 2 masks R /28 [120/2] via , 00:00:01, Serial0/0/0 R /28 [120/2] via , 00:00:01, Serial0/0/0 C /24 is directly connected, Loopback0 C /24 is directly connected, FastEthernet0/0 R /24 [120/2] via , 00:00:01, Serial0/0/0 R /24 [120/2] via , 00:00:01, Serial0/0/0 /30 is subnetted, 2 subnets R [120/1] via , 00:00:02, Serial0/0/0 C is directly connected, Serial0/0/0 /16 is subnetted, 1 subnets R [120/1] via , 00:00:02, Serial0/0/0 R /16 [120/1] via , 00:00:02, Serial0/0/0 Fully converged routing tables. Fully converged routing tables.

R3# show ip route /16 is variably subnetted, 6 subnets, 2 masks C /28 is directly connected, Loopback2 C /28 is directly connected, Loopback1 R /24 [120/2] via , 00:00:01, Serial0/0/1 R /24 [120/2] via , 00:00:01, Serial0/0/1 C /24 is directly connected, FastEthernet0/0 C /24 is directly connected, Loopback0 /30 is subnetted, 2 subnets C is directly connected, Serial0/0/1 R [120/1] via , 00:00:02, Serial0/0/1 /16 is subnetted, 1 subnets R [120/1] via , 00:00:02, Serial0/0/1 R /16 [120/1] via , 00:00:02, Serial0/0/1 Fully converged routing tables. Fully converged routing tables.

R2# debug ip rip RIP: received v2 update from on Serial0/0/1 /24 via in 1 hops /24 via in 1 hops /28 via in 1 hops /28 via in 1 hops RIP: sending v2 update to via Serial0/0/0 ( ) RIP: build update entries /16 via , metric 1, tag 0 /24 via , metric 2, tag 0 /24 via , metric 2, tag 0 /28 via , metric 2, tag 0 /28 via , metric 2, tag 0 /16 via , metric 1, tag 0 /30 via , 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. Sending and receiving routing updates, which are individual routes with their subnet mask instead of a single summary route with the classful mask.

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

RIPv2 and VLSM RIPv2 and CIDR
VLSM and CIDR RIPv2 and VLSM RIPv2 and CIDR

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

RIPv2 and VLSM R3# debug ip rip
RIP: sending v2 update to via FastEthernet0/0 ( ) RIP: build update entries /16 via , metric 2, tag 0 /24 via , metric 3, tag 0 /24 via , metric 3, tag 0 /24 via , metric 1, tag 0 /28 via , metric 1, tag 0 /28 via , metric 1, tag 0 /16 via , metric 2, tag 0 /30 via , metric 2, tag 0 /30 via , metric 1, tag 0

RIPv2 and CIDR R2(config)# ip route Null0 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. 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.

RIPv2 and CIDR R2# debug ip rip RIP: sending v2 update to via Serial0/0/0 ( ) RIP: build update entries /16 via , metric 1, tag 0 /24 via , metric 2, tag 0 /24 via , metric 2, tag 0 /28 via , metric 2, tag 0 /28 via , metric 2, tag 0 /16 via , metric 1, tag 0 /30 via , metric 1, tag 0 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. 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.

RIPv2 and CIDR R1# show ip route
/16 is variably subnetted, 6 subnets, 2 masks R /28 [120/2] via , 00:00:01, Serial0/0/0 R /28 [120/2] via , 00:00:01, Serial0/0/0 C /24 is directly connected, Loopback0 C /24 is directly connected, FastEthernet0/0 R /24 [120/2] via , 00:00:01, Serial0/0/0 R /24 [120/2] via , 00:00:01, Serial0/0/0 /30 is subnetted, 2 subnets R [120/1] via , 00:00:02, Serial0/0/0 C is directly connected, Serial0/0/0 /16 is subnetted, 1 subnets R [120/1] via , 00:00:02, Serial0/0/0 R /16 [120/1] via , 00:00:02, Serial0/0/0 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.

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

show ip route Command R1# show ip route /16 is variably subnetted, 6 subnets, 2 masks R /28 [120/2] via , 00:00:01, Serial0/0/0 R /28 [120/2] via , 00:00:01, Serial0/0/0 C /24 is directly connected, Loopback0 C /24 is directly connected, FastEthernet0/0 R /24 [120/2] via , 00:00:01, Serial0/0/0 R /24 [120/2] via , 00:00:01, Serial0/0/0 /30 is subnetted, 2 subnets R [120/1] via , 00:00:02, Serial0/0/0 C is directly connected, Serial0/0/0 /16 is subnetted, 1 subnets R [120/1] via , 00:00:02, Serial0/0/0 R /16 [120/1] via , 00:00:02, Serial0/0/0 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. 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.

show ip interface brief Command
R1# show ip interface brief Interface IP-Address OK? Method Status Protocol FastEthernet0/ YES NVRAM up up FastEthernet0/ YES NVRAM up up Serial0/0/ YES NVRAM up up Serial0/0/ unassigned YES NVRAM down down 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. 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.

show ip protocols Command
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/ FastEthernet0/ Serial0/0/ Automatic network summarization is not in effect Maximum path: 4 Routing for Networks: Routing Information Sources: Gateway Distance Last Update :00:18 Distance: (default is 120) 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. Is RIP is enabled, the version of RIP, the status of automatic summarization, and the networks that were included in the network statements.

debug ip rip Command R2# debug ip rip
RIP: received v2 update from on Serial0/0/1 /24 via in 1 hops /24 via in 1 hops /28 via in 1 hops /28 via in 1 hops RIP: sending v2 update to via Serial0/0/0 ( ) RIP: build update entries /16 via , metric 1, tag 0 /24 via , metric 2, tag 0 /24 via , metric 2, tag 0 /28 via , metric 2, tag 0 /28 via , metric 2, tag 0 /16 via , metric 1, tag 0 /30 via , metric 1, tag 0 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.

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

show running-config Command
R1# show running-config ! hostname R1 interface FastEthernet0/0 ip address interface FastEthernet0/1 ip address interface Serial0/0/0 ip address clock rate 64000 router rip version 2 network network no auto-summary <some output omitted for brevity>

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: It enables the routing protocol to send and receive updates on any local interfaces that belong to that network. 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. 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: It enables the routing protocol to send and receive updates on any local interfaces that belong to that network. 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.

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. 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.

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

Chapter 7 RIP version 2 CIS 82 Routing Protocols and Concepts
Rick Graziani Cabrillo College

Chapter 7 RIP version 2 CIS 82 Routing Protocols and Concepts

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Chapter 7 RIP version 2 CIS 82 Routing Protocols and Concepts

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