Download - CA Ex s2m07 Ripv2
CCNA – Semester 2
Chapter 7: RIPv2
CCNA Exploration version 4.0
2
Overview
3
RIPv1 Limitations
4
Lab Topology
• 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
5
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.
6
Lab Topology: Private Address
7
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.
8
RIPv1 Topology Limitations
9
RIPv1 Topology Limitations
• Static Routes and Null Interfaces
10
RIPv1 Topology Limitations
• Verifying and Testing Connectivity
11
RIPv1 Topology Limitations
• Verifying and Testing Connectivity
12
RIPv1 Topology Limitations
• Use the Packet Tracer Activity to practice your router configuration skills,
including RIPv1 configurations. 7.1.2.3
13
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.
14
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.
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RIPv1: Discontiguous Networks
16
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.
19
RIPv1: No CIDR support
• 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.
20
RIPv1: No CIDR support
21
RIPv1: No CIDR support
• 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
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Configuring RIPv2
23
Enabling and Verifying RIPv2
• 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.
24
Enabling and Verifying RIPv2
25
Auto-summary and RIPv2
• By default, RIPv2 automatically summarizes networks at major
network boundaries, just like RIPv1.
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Auto-summary and RIPv2
27
Auto-summary and RIPv2
28
Auto-summary and RIPv2
• 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.
29
Disabling Auto-summay in RIPv2
30
Verifying RIPv2 Updates
31
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
33
Compatibility with RIP v1
NewYork
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
• 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.
RIPv2
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Adding a default Routes to RIPv2
e0
ISP
SantaCruz2SantaCruz1
192.168.4.20/30
172.30.1.0/24
Internet
s0
s0 s0
s1
172.30.100.0/24
e0
192.168.4.24/30
.21
.22
.25
.26
10.0.0.0/8
e0.1
.1.1
Lo0Lo0
172.30.110.0/24172.30.2.0/24
.1.1
.1
static route to
207.0.0.0/8
207.0.0.0/16
207.1.0.0/16
207.2.0.0/16
207.3.0.0/16
etc.
`172.30.200.16/28
172.30.200.32/28
Lo1
Lo2
ISP
router rip
redistribute static
network 10.0.0.0
network 192.168.4.0
version 2
no auto-summary
default-information originate
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
35
VLSM and CIDR
36
RIPv2 and VLSM
37
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.
38
RIPv2 and CIDR
39
Verifying and Troubleshooting RIPv2
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Verification and Troubleshooting Commands
• 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
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 192.168.4.21, 00:00:21, Serial0
R 172.30.1.0/24 [120/2] via 192.168.4.21, 00:00:21, Serial0
C 172.30.100.0/24 is directly connected, Ethernet0
C 172.30.110.0/24 is directly connected, Loopback0
192.168.4.0/30 is subnetted, 2 subnets
R 192.168.4.24 [120/1] via 192.168.4.21, 00:00:21, Serial0
C 192.168.4.20 is directly connected, Serial0
R 10.0.0.0/8 [120/1] via 192.168.4.21, 00:00:21, Serial0
R 207.0.0.0/8 [120/1] via 192.168.4.21, 00:00:21, Serial0
Supernet, classless routing protcols
will route supernets (CIDR)
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Verification and Troubleshooting Commands
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Verification and Troubleshooting Commands
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Verification and Troubleshooting Commands
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
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
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
<text omitted>
Router(config)# line console 0
Router(config-line)# logging synchronous
multicast
Includes mask
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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.
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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.
50
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.
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RIPv2 Configuration Labs
52
Summary