Networking Chapter 9 Ccna Guide Cisco Networking Fundamentals Fourth Edition Router Startup And Configuration

CCNA Guide to Cisco Networking Fundamentals, Fourth Edition 6-1

Chapter 6

Router Startup and Configuration

At a Glance

Instructor’s Manual Table of Contents

• Overview

• Objectives

• Teaching Tips

• Quick Quizzes

• Class Discussion Topics

• Additional Projects

• Additional Resources

• Key Terms

CCNA Guide to Cisco Networking Fundamentals, Fourth Edition 6-2

Lecture Notes

Overview

In this chapter, you will learn about the various configurable components of the Cisco

router and how to manipulate them. The chapter describes basic router configuration and

administrative tasks, and introduces the CDP protocol and its configuration. In addition,

you will learn how to configure and test IP. You will also learn the steps involved in

troubleshooting connectivity problems on a Cisco router.

Chapter Objectives

• Describe the steps involved in starting a router

• Describe and use the Cisco Discovery Protocol

• Configure IP on the Cisco router

• Troubleshoot router connectivity problems

Teaching Tips

Router Startup

1. Use Figure 6-1 to describe the general steps in a router’s boot process, including:

a. Test hardware (POST)

Test Hardware (POST)

1. Mention that read-only memory (ROM) in a router typically contains the power-on self-

test (POST), the bootstrap program, and often a version of the operating system.

3. Explain that during the POST, the bootstrap program, also called the ROM Monitor,

checks basic operations of the attached hardware. The ROM Monitor checks the

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Router Configuration Files

1. Define startup-config as the router configuration file that loads during the boot process.

2. Explain that to revert to the settings in your startup-config, you can reboot the system

3. Note that when you copy over the startup configuration in NVRAM, that file is

4. To view the contents of the startup-config, type show startu-pconfig or just

5. Use Table 6-1 to describe different important copy and configure commands.

Teaching

Tip

Notice there is no copy command that copies between flash and a running or

startup configuration file. It is important to think of the IOS and configuration

files as separate.

Methods for Making Changes

1. Mention that you can usually implement and test changes without saving them to the

startup configuration.

2. Describe the basic steps to implement changes:

a. Make changes as desired to the configuration

b. Examine those changes

c. Determine if the changes meet the desired result

d. Remove the changes if they do not meet the desired result, or simply reboot the

router

e. Copy the changes from the running configuration to the startup configuration

when they do meet the desired result

IP on the Router

CCNA Guide to Cisco Networking Fundamentals, Fourth Edition 6-4

Teaching

Tip

Notice that the subnet mask needs to be included in the ip address

command. The command would be incomplete without the subnet mask. You

can also add the word secondary to an ip address command and

configure the address as a second IP address for the interface.

2. Mention that when you configure a serial interface as a DCE (data communication

equipment), you will also need to add the clockrate [bandwidth in bits per second]

command.

IP Connectivity

1. Use Table 6-2 to show some of the commands used to test for connectivity by layers.

Telnet

1. Define Telnet as a utility that connects at the highest layer of the OSI model and

provides remote access to other devices.

3. Explain that if you can establish telnet connectivity to a router, you have established

that it is available on the network and that you have connectivity at all layers.

Teaching

Tip

After you establish telnet connectivity, you can learn more about the

configuration of the remote router by executing commands as if you were

connected to the router locally.

IP Host Names

1. Mention that sometimes, you cannot gain connectivity because the host name that you

are trying to connect with is entered in a table incorrectly.

3. Mention that if you want to add an entry to your hosts file for name resolution, you

4. Explain how to allow a name server to handle the IP address to name resolution by

CCNA Guide to Cisco Networking Fundamentals, Fourth Edition 6-5

Ping and Trace

1. Mention that Ping and Trace verify connectivity at the Internetwork layer of the TCP/IP

model.

2. Explain that Ping can return the following replies:

a. ! Successful receipt of the ICMP echo

b. . Request timed out

4. Explain that Trace sends multiple ICMP packets with progressively higher time-to-live

counters (TTL) until the packet reaches the destination. The following responses can be

returned by a trace:

a. !H Indicates that a router received, but did not forward, the ICMP

echo

request

b. P Protocol unreachable

IP Route

1. Explain that if you cannot get connectivity using Ping or Trace, you should check your

2. Mention that typically, routing tables are dynamically created when routing protocols

are configured on the router. If you want, you can use the ip route command from

the global configuration mode to statically enter routes in the routing table.

Quick Quiz 1

1. ____ is a diagnostic test that determines if the hardware is operating correctly.

Teaching

Tip

The trace command is useful for determining where in the process the

communication is breaking down.

2. The ____ checks the configuration register for instructions regarding how to load the

Cisco IOS.

3. ____ is a utility that connects at the highest layer of the OSI model and provides remote

access to other devices.

4. If you want to add an entry to your hosts file for name resolution, you must go to ____

mode.

Checking the Interface

1. Explain that the show interfaces command checks the configuration of a specific

interface from the enable mode prompt. Example: router#show int s0/0.

2. Use Figure 6-2 to describe some of the replies for the show interface command,

including the following:

3. Mention that the router keeps detailed statistics regarding data passing across its

4. Explain that the debug command is one of the most powerful tools you can use to

obtain information from your router. This tool is only available from privileged EXEC

mode. Debug has numerous subcommands. Use Figure 6-3 to illustrate your

Teaching

Tip

With debug, you can also check for specific types of traffic on the wire. For

example, if you want to perform general IP packet debugging, type the

following: router#debug ip packet.

CDP

1. Define Cisco Discovery Protocol (CDP) as a Cisco proprietary Data Link layer protocol

2. Explain that all Cisco devices can use CDP to discover each other and learn about the

3. Mention that CDP was designed to be a low-overhead protocol.

Teaching

Tip

By default, CDP is enabled on all Cisco devices, but you can modify CDP

broadcasts on the network. To turn off CDP on the entire router, use the no cdp

run command at the global configuration prompt.

Cisco IOS

1. Explain that the Cisco IOS is usually loaded from flash memory. If the router cannot

2. Mention that if you want to see information about your router’s flash memory, type

Configuration Register

1. Mention that every Cisco router has a 16-bit configuration register, which is stored in

NVRAM. This register allows you to control several boot functions, including the

following:

a. Forcing the system into the bootstrap program

2. Explain that you can examine the configuration register by typing show version. Use

CCNA Guide to Cisco Networking Fundamentals, Fourth Edition 6-8

ROM Monitor Mode

1. Define ROM Monitor mode as the bootstrap program that is built into the firmware of

2. To configure your system to enter ROM Monitor mode, enter the following command at

3. To configure your system to boot a smaller IOS image from ROM and enter RxBoot

mode, enter the following command at the global configuration prompt:

Teaching

Tip

Be careful when modifying the configuration register. Using ROM Monitor

mode will not cause problems, but entering random hexadecimal commands

above 0x0002 may present a variety of problems.

RxBoot Mode

2. Mention that if your router enters RxBoot mode without your intervention, it means the

router could not find a good IOS image.

3. Mention that the prompt for RxBoot mode is the host name of your router followed by

Boot System Commands

1. Mention that as long as the configuration register is configured with a 2 as the final

2. To enable your system to boot an IOS file from the TFTP server issue the following

Teaching

Tip

The boot system flash bootflash command will force the router to boot into

ROM.

CCNA Guide to Cisco Networking Fundamentals, Fourth Edition 6-9

Backing Up and Restoring the IOS

1. Explain that copy flash tftp is the command for backing up your IOS to a TFTP

Upgrading the IOS

1. Explain that before you load a new IOS file to your router, you should use the show

2. Mention that if there is not enough memory to hold both the current IOS image and the

Router Password Recovery

1. Define password recovery as the process that allows you to get into the router without

2. Describe the steps to perform password recovery on the Cisco 2600 series:

a. Connect to the router from a PC using the console port and the HyperTerminal

program

b. Enter the show version command and record the value of the configuration

register

CCNA Guide to Cisco Networking Fundamentals, Fourth Edition 6-10

Security Device Manager

2. Explain that SDM is commonly used to configure routing protocols, WAN services,

3. Mention that SDM is typically not used to configure basic functionality on a Cisco

router and, in fact, SDM cannot do all things.

Quick Quiz 2

1. ____mode is actually the bootstrap program that is built into the firmware of the router.

2. ROM in the router contains a limited version of the IOS. When accessing this limited

IOS version, you are in ____ mode.

3. A procedure called ____ on Cisco routers allows you to get into the router without the

necessary passwords.

4. ____ is a Web-based tool primarily used for implementing and testing security

configurations.

Class Discussion Topics

1. What are the tasks performed by the Ping and Trace utilities?

2. Why would you want to access the RxBoot mode in a router?

Additional Projects

1. CDP was designed to be a low-overhead protocol. Ask your students to write a report

2. Ask your students to read the following article about recovering lost passwords using

Additional Resources

3. Telnet

4. The Story of the PING Program

5. Traceroute Command

6. Cisco Discovery Protocol

Key Terms

➢ Cisco Discovery Protocol (CDP) A Cisco proprietary Data Link layer protocol that

shares configuration information between Cisco devices that are locally connected.

➢ DCE (data communication equipment) Equipment that performs some type of signal

conversion between the terminal device and the transmission facility. Usually the DCE

is part of the telco provider’s equipment.

➢ global configuration mode A router mode that allows you to manipulate most of the

router’s generic settings. The prompt for global configuration mode is router(config)#.

➢ keepalive frames Data frames sent between two hosts to ensure that the connection

between those hosts remains open.

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➢ ROM Monitor A bootstrap program that runs during the power-on self-test and checks

basic operations of hardware, including CPU, memory, and interfaces.

➢ ROM Monitor mode A router mode in which you can configure the router manually.

➢ RxBoot mode A configuration mode that can be entered when changes to a system

make it impossible to boot from the flash memory and a valid IOS image cannot be