CCNA6-12

Exam Essentials 401
Interface Send Recv Triggered RIP Key-chain
FastEthernet0/1 2 2
Serial0/0/1 2 2
Automatic network summarization is not in effect
Maximum path: 4
Routing for Networks:
10.0.0.0
Passive Interface(s):
FastEthernet0/0
Serial0/0/0
Routing Information Sources:
Gateway Distance Last Update
10.1.11.2 120 00:00:00
10.1.5.1 120 00:00:02
Distance: (default is 120)
We are now sending and receiving RIPv2. Nice when things work out well, huh? You’re
ready now to move on to the next chapter!
Summary
This chapter covered IP routing in detail. It’s extremely important that you really understand
the basics we covered in this chapter because everything that’s done on a Cisco router typically
will have some type of IP routing configured and running.
You learned in this chapter how IP routing uses frames to transport packets between routers
and to the destination host. From there, we configured static routing on our routers and
discussed the administrative distance used by IP to determine the past route to a destination
network. If you have a stub network, you can configure default routing, which sets the gateway
of last resort on a router.
We then discussed dynamic routing in detail, specifically RIP and how it works on an internetwork
(not well). We finished by verifying RIP and then adding RIPv2 to our little internetwork.
In the next chapter, we’ll continue on with dynamic routing by discussing EIGRP and OSPF.
Exam Essentials
Understand the basic IP routing process. You need to remember that the frame changes at
each hop but that the packet is never changed or manipulated in any way until it reaches the
destination device.
402 Chapter 6  IP Routing
Understand that MAC addresses are always local. A MAC (hardware) address will only be
used on a local LAN. It will never pass a router’s interface.
Understand that a frame carries a packet to only two places. A frame uses MAC (hardware)
addresses to send a packet on a LAN. The frame will take the packet to either a host on
the LAN or a router’s interface if the packet is destined for a remote network
Understand how to configure RIP routing. To configure RIP routing, first you must be in
global configuration mode and then you type the command router rip. Then you add all
directly connected networks, making sure to use the classful address.
Remember how to verify RIP routing. The show ip route command will provide you with
the contents of the routing table. An R on the left side of the table indicates a RIP-found route.
The debug ip rip command will show you RIP updates being sent and received on your
router. If you see a route with a metric of 16, that route is considered down.
Remember the differences between RIPv1 and RIPv2. RIPv1 sends broadcasts every 30 seconds
and has an AD of 120. RIPv2 sends multicasts (224.0.0.9) every 30 seconds and also has
an AD of 120. RIPv2 sends subnet mask information with the route updates, which allows it
to support classless networks and discontiguous networks. RIPv2 also supports authentication
between routers and RIPv1 does not.
Written Lab 6
Write the answers to the following questions:
1. Create a static route to network 172.16.10.0/24 with a next-hop gateway of 172.16.20.1
and an administrative distance of 150.
2. From the SDM you have just enabled RIP and the passive-interface box for your serial
interface is unchecked. What does this mean?
3. What command will you type to create a default route to 172.16.40.1?
4. If you are using default routing, what command must also be used?
5. You would use a default route on which type of network?
6. To see the routing table on your router, what command will you use?
7. When creating a static or default route, you don’t have to use the next-hop IP address; you
can use the ___________________.
8. True/False: To reach a destination host, you must know the MAC address of the remote
host.
9. True/False: To reach a destination host, you must know the IP address of the remote host.
10. If you have a DCE serial interface, what command must you enter for that interface
to work?
Hands-on Labs 403
11. Write the commands used to turn RIP routing on in a router and advertise network
10.0.0.0.
12. Write the commands to stop a router from propagating RIP information out serial 1.
13. What works with triggered updates to help stop routing loops in distance-vector networks?
14. What stops routing loops in distance-vector networks by sending out a maximum hop
count as soon as a link fails?
15. What stops routing loops in distance-vector networks by not resending information
learned on an interface out that same interface?
16. What command is used to send RIP routing updates as they are sent and received on the
router to the console session?
(The answers to Written Lab 6 can be found following the answers to the review questions
for this chapter.)
Hands-on Labs
In the following hands-on labs, you will configure a network with three routers.
The hands-on labs in this section is included for use with real Cisco routers.
If you are using software from RouterSim or Sybex, please use the hands-on
labs found in those programs.
This chapter includes:
Lab 6.1: Creating Static Routes
Lab 6.2: Configuring RIP Routing
Figure 6.17 will be used to configure all routers.
FIGURE 6 . 1 7 Hands-on lab internetwork
Lab_A Lab_B Lab_C
fa0/0 fa0/0
s0/0
(DCE) s0/0
s0/1
(DCE)
s0/0
404 Chapter 6  IP Routing
Table 6.5 shows our IP addresses for each router (each interface uses a /24 mask).
These labs were written without using the LAN interface on the Lab_B router. You can
choose to add that LAN into the labs if necessary.
Hands-on Lab 6.1: Creating Static Routes
In this lab, you will create a static route in all three routers so that the routers see all networks.
Verify with the Ping program when complete.
1. The Lab_A router is connected to two networks, 172.16.10.0 and 172.16.20.0. You need
to add routes to networks 172.16.30.0 and 172.16.40.0.
Lab_A#config t
Lab_A(config)#ip route 172.16.30.0 255.255.255.0
172.16.20.2
Lab_A(config)#ip route 172.16.40.0 255.255.255.0
172.16.20.2
2. Save the current configuration for the Lab_A router by going to the privileged mode, typing
copy run start, and pressing Enter.
3. On the Lab_B router, you have direct connections to networks 172.16.20.0 and
172.16.30.0. You need to add routes to networks 172.16.10.0 and 172.16.40.0.
Lab_B#config t
Lab_B(config)#ip route 172.16.10.0 255.255.255.0
172.16.20.1
Lab_B(config)#ip route 172.16.40.0 255.255.255.0
172.16.30.2
TABLE 6 . 5 Our IP Addresses
Router Interface IP Address
Lab_A F0/0 172.16.10.1
Lab_A S0/0 172.16.20.1
Lab_B S0/0 172.16.20.2
Lab_B S0/1 172.16.30.1
Lab_C S0/0 172.16.30.2
Lab_C Fa0/0 172.16.40.1