Ca Ex S2m07 Ripv2

CCNA – Semester 2

Chapter 7: RIPv2 CCNA Exploration version 4.0

Overview

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RIPv1 Limitations

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Lab Topology

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This topology is discontiguous and will not converge because 172.30.0.0/16 is divided by the 209.165.200.0/24. R2 router has a static summary route to the 192.168.0.0/16 network. For now, understand that this summary route will cause problems with RIPv1 because 192.168.0.0/16 is not a major classful address and includes all of the /24 versions of 192.168.0.0/16 4

VLSM

• Notice that the R1 and R3 routers contain VLSM networks and are sharing address space from the 172.30.0.0/16 major classful network. 5

Lab Topology: Private Address

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Lab Topology: Loopback interface

• A loopback interface is a software-only interface that is used • •

to emulate a physical interface. Like other interfaces, it can be assigned an IP address. Loopback interfaces are also used by other routing protocols, such as OSPF, for different purposes. 7

RIPv1 Topology Limitations

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RIPv1 Topology Limitations •

Static Routes and Null Interfaces

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RIPv1 Topology Limitations •

Verifying and Testing Connectivity

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RIPv1 Topology Limitations • Verifying and Testing Connectivity

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RIPv1 Topology Limitations

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Use the Packet Tracer Activity to practice your router configuration skills, including RIPv1 configurations. 7.1.2.3 12

RIPv1: Discontiguous Networks

• RIPv1 is a classful routing protocol. • It does not include the subnet masks in its routing updates. • Therefore, RIPv1 cannot support discontiguous networks, VLSM, or Classless Inter-Domain Routing (CIDR) supernets. 13

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. 14

RIPv1: Discontiguous Networks

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RIPv1: Discontiguous Networks

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RIPv1: Discontiguous Networks

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RIPv1: No VLSM Support

• •

Because RIPv1 does not send the subnet mask in routing updates, it cannot support VLSM. RIPv1 either summarizes the subnets to the classful boundary or uses the subnet mask of the outgoing interface to determine which subnets to advertise.

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RIPv1: No CIDR support

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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. 19

RIPv1: No CIDR support

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RIPv1: No CIDR support

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Use the Packet Tracer Activity in Simulation mode to see that updates are not sent across classful network boundaries with RIPv1. In RealTime mode, verify non-convergence with the show ip route, ping, and debug ip rip. 7.1.5.2 21

Configuring RIPv2

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Enabling and Verifying RIPv2

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The Next Hop address is used to identify a better next-hop address - if one exists - than the address of the sending router. If the field is set to all zeros (0.0.0.0), the address of the sending router is the best next-hop address. 23

Enabling and Verifying RIPv2

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Auto-summary and RIPv2

• By default, RIPv2 automatically summarizes networks at major network boundaries, just like RIPv1. 25

Auto-summary and RIPv2

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Auto-summary and RIPv2

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Auto-summary and RIPv2

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Remember, the 192.168.0.0/16 route could not be distributed with RIPv1 because the subnet mask was less than the classful mask. Because the mask is not included in RIPv1 updates, there was no way for the RIPv1 router to determine what that mask should be. Therefore, the update was never sent. 28

Disabling Auto-summay in RIPv2

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Verifying RIPv2 Updates

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Verifying RIPv2 Updates

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Verifying RIPv2 Updates

• Use the Packet Tracer Activity to configure RIPv2, disable automatic summarization, and verify your configurations. 7.2.4.2 32

Compatibility with RIP v1 NewYork

RIPv2

• • •

Interface FastEthernet0/0 is configured to send and receive RIP v1 updates. FastEthernet0/1 is configured to send both version 1 and 2 updates. FastEthernet0/2 has no special configuration and therefore sends and receives version 2 by default.

interface fastethernet0/0 ip address 192.168.50.129 255.255.255.192 ip rip send version 1 ip rip receive version 1 interface fastethernet0/1 ip address 172.25.150.193 255.255.255.240 ip rip send version 1 2 interface fastethernet0/2 ip address 172.25.150.225 225.255.255.240 router rip version 2 network 172.25.0.0 network 192.168.50.0 33

Adding a default Routes to RIPv2 207.0.0.0/16 207.1.0.0/16 207.2.0.0/16 207.3.0.0/16 etc.

Internet

ISP router rip redistribute static network 10.0.0.0 network 192.168.4.0 version 2 no auto-summary default-information originate

10.0.0.0/8 .1

.1 e0

ISP .25

s0

s1

.21

192.168.4.24/30

192.168.4.20/30 172.30.200.32/28 Lo2

.26

172.30.2.0/24

s0

Lo0 .1 SantaCruz1 .1 e0

ip route 207.0.0.0 255.0.0.0 null0 ip route 0.0.0.0 0.0.0.0 10.0.0.2 etherenet0

static route to 207.0.0.0/8

172.30.1.0/24

s0

.22

Lo1

`

172.30.200.16/28

SantaCruz2 Lo0 .1 e0

.1

172.30.110.0/24

172.30.100.0/24

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VLSM and CIDR

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RIPv2 and VLSM

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RIPv2 and CIDR

• One of the goals of Classless Inter-Domain Routing (CIDR) as

•

stated by RFC 1519 is "to provide a mechanism for the aggregation of routing information." This goal includes the concept of supernetting. A supernet is a block of contiguous classful networks that is addressed as a single network. 37

RIPv2 and CIDR

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Verifying and Troubleshooting RIPv2

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Verification and Troubleshooting Commands

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There are several ways to verify and troubleshoot RIPv2. Many of the same commands used for RIPv2 can be used to verify and troubleshoot other routing protocols. It is always best to begin with the basics: 1. Make sure all of the links (interfaces) are up and operational. 2. Check the cabling. 3. Check to make sure you have the correct IP address and subnet mask on each interface. 4. Remove any unnecessary configuration commands that are no longer necessary or have been replaced by other commands.

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Verification and Troubleshooting Commands Router#show ip route

C C R R C C R C R R

172.30.0.0/16 is variably subnetted, 6 subnets, 2 masks 172.30.200.32/28 is directly connected, Loopback2 172.30.200.16/28 is directly connected, Loopback1 172.30.2.0/24 [120/2] via 192.168.4.21, 00:00:21, Serial0 172.30.1.0/24 [120/2] via 192.168.4.21, 00:00:21, Serial0 172.30.100.0/24 is directly connected, Ethernet0 172.30.110.0/24 is directly connected, Loopback0 192.168.4.0/30 is subnetted, 2 subnets 192.168.4.24 [120/1] via 192.168.4.21, 00:00:21, Serial0 192.168.4.20 is directly connected, Serial0 10.0.0.0/8 [120/1] via 192.168.4.21, 00:00:21, Serial0 207.0.0.0/8 [120/1] via 192.168.4.21, 00:00:21, Serial0

Supernet, classless routing protcols will route supernets (CIDR) 41

Verification and Troubleshooting Commands

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Verification and Troubleshooting Commands

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Verification and Troubleshooting Commands Router(config)# line console 0 Router(config-line)# logging synchronous Router#debug ip rip RIP protocol debugging is on Router#01:23:34: RIP: received v2 update from 192.168.4.22 on Serial1 01:23:34: 172.30.100.0/24 -> 0.0.0.0 in 1 hops 01:23:34: 172.30.110.0/24 -> 0.0.0.0 in 1 hops Includes mask Router# 01:23:38: RIP: received v2 update from 192.168.4.26 on Serial0 01:23:38: 172.30.2.0/24 -> 0.0.0.0 in 1 hops 01:23:38: 172.30.1.0/24 -> 0.0.0.0 in 1 hops multicast Router# 01:24:31: RIP: sending v2 update to 224.0.0.9 via Ethernet0 (10.0.0.1) 01:24:31: 172.30.2.0/24 -> 0.0.0.0, metric 2, tag 0 01:24:31: 172.30.1.0/24 -> 0.0.0.0, metric 2, tag 0 01:24:31: 172.30.100.0/24 -> 0.0.0.0, metric 2, tag 0 01:24:31: 172.30.110.0/24 -> 0.0.0.0, metric 2, tag 0 01:24:31: 192.168.4.24/30 -> 0.0.0.0, metric 1, tag 0 01:24:31: 192.168.4.20/30 -> 0.0.0.0, metric 1, tag 0 44

Verification and Troubleshooting Commands

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Verification and Troubleshooting Commands

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Verification and Troubleshooting Commands Router# show ip rip database 172.19.0.0/16 auto-summary 172.19.64.0/24 directly connected, Ethernet0 172.19.65.0/24 [1] via 172.19.70.36, 00:00:17, Serial1 [2] via 172.19.67.38, 00:00:25, Serial0 172.19.67.0/24 directly connected, Serial0 172.19.67.38/32 directly connected, Serial0 172.19.70.0/24 directly connected, Serial1 172.19.86.0/24[1] via 172.19.67.38, 00:00:25, Serial0 [1] via 172.19.70.36, 00:00:17, Serial1

• • •

The show ip rip database command to check summary address entries in the RIP database. These entries will appear in the database if there are only relevant child or specific routes being summarized. When the last child route for a summary address becomes invalid, the summary address is also removed from the routing table. Router#show ip rip database

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Common RIPv2 issues

• The network statement does two things: – It enables the routing protocol to send and receive updates on any local interfaces that belong to that network. – It includes that network in its routing updates to its neighboring routers. 48

Authentication

• • • •

Whatever the reason, it is good practice to authenticate routing information transmitted between routers. RIPv2, EIGRP, OSPF, IS-IS, and BGP can be configured to authenticate routing information. This practice ensures routers will only accept routing information from other routers that have been configured with the same password or authentication information. Note: Authentication does not encrypt the routing table. 49

Configuring authentication

•

•

Router(config)#key chain Romeo Router(config-keychain)#key 1 Router(config-keychain-key)#key-string Juliet The password must be the same on both routers (Juliet), but the name of the key (Romeo) can be different. Router(config)#interface fastethernet 0/0 Router(config-if)#ip rip authentication key-chain Romeo Router(config-if)#ip rip authentication mode md5 If the command ip rip authentication mode md5 is not added, the interface will use the default clear text authentication. Although clear text authentication may be necessary to communicate with some RIP v2 implementations, for security concerns use the more secure MD5 authentication whenever possible. 50

RIPv2 Configuration Labs

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Summary

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