CCNA Guide to Cisco Networking Fundamentals, Fourth Edition 5-1
Chapter 5
Router and IOS Basics
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 5-2
Lecture Notes
Overview
This chapter delves deeper into the benefits of routing. You will learn about the elements of
the Cisco user interface, including the system configuration dialog, various configuration
modes, and the many Cisco router passwords. You will also configure the Windows
program HyperTerminal for use with the router. In addition, you will explore the enhanced
editing features of the Cisco IOS and router components.
Chapter Objectives
• Describe the benefits of network segmentation with routers
• Understand the elements of the Cisco router user interface
• Configure the HyperTerminal program to interface with the Cisco router
• Describe the various router configuration modes
• Describe the various router passwords
• Understand the enhanced editing features of the Cisco IOS
• Compare router components to typical PC components
Teaching Tips
Benefits of Routing
2. Mention that routers operate at the Network layer of the OSI reference model and
Cisco Router User Interface
1. Explain that the Cisco Internetwork Operating System (IOS) provides a command-line
2. Use Figures 5-1 and 5-2 to describe the following methods to access a router:
a. Console port (also known as the console)
b. Auxiliary port (AUX)
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Teaching
Tip
Read more about Cisco IOS at: http://en.wikipedia.org/wiki/Cisco_IOS.
Connecting via Terminal Programs
1. Explain that when configuring the router through the console or AUX ports, you must
2. Describe the following steps to configure HyperTerminal:
a. Open the HyperTerminal application
b. Click File on the menu bar, and then click New Connection
c. Enter a name for the connection
d. Configure how you will connect to the router via the Connect To dialog box
e. Configure the following settings for the COM port: Bits per second, 9600; Data
bits, 8; Parity, None; Stop bits, 1; Flow control, None
Teaching
Tip
If you are using Vista, you can download a free personal edition of
HyperTerminal from www.hilgraeve.com/htpe/download.html.
System Configuration Dialog
1. Mention that if the router has not been configured previously, or if the startup file has
been erased, the Cisco IOS will prompt you to run the initial configuration dialog after
the router boots.
Teaching
Tip
You can also access the system configuration dialog by typing the setup
command at the privileged EXEC prompt.
2. Explain that the system configuration dialog presents a series of prompts that guide you
through the initial configuration for the router. Use Figure 5-3 to illustrate your
explanation.
User Interface
2. Explain that the User EXEC mode (or user mode), when the prompt displayed is the
3. Mention that the question mark activates context-sensitive Help on the Cisco router.
Use Figure 5-4 to illustrate your explanation.
5. Explain that to enter privileged EXEC, you can type the enable command at the user
6. Describe some of the tasks you can do at this prompt, such as the following:
Teaching
Tip
Privileged EXEC mode is called enable mode because you must enter the
enable command to access it.
Configuration Modes
1. Mention that the global configuration mode is accessed by typing configure terminal at
2. Explain that the interface configuration mode allows you to configure the Ethernet and
4. Mention that typing exit will take you back one level. Typing end or pressing the
Ctrl+Z keys will take you all the way back to the enable prompt.
5-5 to illustrate your explanation.
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Quick Quiz 1
1. Network administrators commonly configure and interact with a Cisco router via the
Cisco ____ (IOS).
2. The ____ dialog presents a series of prompts that guide you through the initial
configuration for the router.
3. When the prompt displayed is the greater than symbol, the router is in ____ mode (or
user mode).
4. Privileged EXEC mode is called ____ mode because you must enter the enable
command to access it.
Plethora of Passwords
1. Use Table 5-2 to describe the five passwords on a Cisco router: enable, enable secret,
console, AUX, and virtual terminal.
3. Mention that because it is encrypted, the enable secret password is more secure than the
enable password. Use Figure 5-7 to illustrate your explanation.
5. Explain that line passwords are the first line of defense against unauthorized intrusion
into the router. You can set passwords for each line used to configure the router.
7. Mention that you can also configure passwords on the five virtual terminal lines that
Enhanced Editing
1. Mention that by default, the router supports enhanced editing features that allow you to
2. Explain that the enhanced editing commands let you jump to the beginning or end of a
3. Mention that you can turn off the enhanced editing features by typing terminal no
editing at either the user EXEC or the privileged EXEC prompts. You can turn on
terminal editing by typing terminal editing.
Teaching
Tip
When you type an incorrect command, the bogus command might be mistaken
for a host name. If this happens, the router will, by default, attempt to look up the
host name and give you the corresponding IP address. If you want to prevent the
router from doing this, type no ip domain-lookup at the global
configuration prompt.
Command History
1. Mention that the command history allows you to retrieve previously typed commands.
3. Explain that to modify the number of commands stored by the router, you can use the
Configuring Router Identification
1. Explain that the default host name is router. To set the router host name, type
hostname followed by the name that you want to set.
2. Define a banner as a message that you can configure to display each time someone
Teaching
Tip
The banner motd command is typically used as a legal means of warning
anyone who accesses the banner that they will be held accountable.
3. Explain that to configure an interface description, you use the description command.
The interface description helps you remember which network the interface services. Use
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Configuring the Time and Date
1. Explain that you use the clock set command in enable mode to configure the time.
You must be in global configuration mode to configure the time zone. Use Figure 5-14
to illustrate your explanation.
Teaching
Tip
When entering the time zone, you must include the name of the time zone and
the offset from the Coordinated Universal Time (UTC). The UTC is based on the
time in Greenwich, a city in the United Kingdom.
Router Components
1. This section discusses following hardware elements of the router:
a. ROM
ROM
1. Explain that the read-only memory (ROM) loads the bootstrap program that initializes
2. Mention that the content of ROM is maintained even when the router is rebooted. The
ROM monitor firmware runs when the router is turned on or rebooted.
Flash Memory
1. Define flash memory as a type of erasable, programmable, read-only memory
(EPROM). It is not typically modified during normal operations; however, it can be
upgraded or erased when necessary.
2. Mention that the content of flash memory is maintained even when the router is
rebooted.
3. Explain that the flash memory contains the working copy of the current Cisco IOS and
is the component that initializes the IOS for normal router operations. Use Figure 5-15
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Teaching
Tip
Flash memory on certain series of Cisco routers can store multiple versions of
the IOS, which can make upgrading the IOS easier and safer.
NVRAM
1. Define the nonvolatile random access memory (NVRAM) as a special type of RAM
that is not cleared when the router is rebooted.
3. Mention that the Cisco IOS uses the configuration file in NVRAM during the router
boot process.
RAM/DRAM
1. Define random access memory (RAM), also known as dynamic random access memory
2. Explain that changes to the router’s running configuration take place in RAM/DRAM.
3. The IOS contains commands such as the following to view each of the router’s
components:
a. show running-config (see Figure 5-16)
Interfaces
1. Explain that a router can ship with a variety of configurable interfaces. A common
interface is Ethernet0. Other types of interfaces include:
2. Explain that you can view all of the configured interfaces for your router with the show
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Quick Quiz 2
1. The default host name is simply ____, which is displayed at the beginning of every
prompt.
2. ____ is a type of erasable, programmable, read-only memory (EPROM).
3. ____ is a special type of RAM that is not cleared when the router is rebooted.
4. You can view all of the configured interfaces for your router with the ____ command.
Class Discussion Topics
1. What are the tasks performed by the Cisco IOS?
2. What are the differences between ROM, Flash memory, NVRAM, and RAM?
Additional Projects
1. IOS Software Modularity is an extension to the Cisco IOS operating system that allows
2. Ask your students to read the following article about how to reset the administrator
password on a Cisco router with SNMP at
Additional Resources
1. Cisco IOS Software
3. Password Recovery Procedures
4. Non-volatile random access memory
5. Dynamic random access memory
6. Flash memory
Key Terms
➢ AUX line password A password used to access the router through the AUX port.
➢ AUX port See auxiliary port (AUX).
rollover cable to attach to a PC for router configuration (also known as a console port).
➢ console password The password that is used to access the router through the console
port.
➢ console port See console.
➢ context-sensitive Help Help with the syntax of commands for the router that is based
secret password has been removed.
➢ enable secret password An MD5-encrypted password that is not visible when viewing
the system configuration; it supersedes the enable password.
➢ EXEC See command executive.
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mode is router(config-line)#.
➢ MD5 algorithm An algorithm used to encrypt an enable secret password.
➢ nonvolatile random access memory (NVRAM) A special type of RAM that is not
cleared when the router is rebooted. The startup configuration file for the router is
stored in NVRAM.
➢ RJ-45 to RJ-45 rollover cable A cable that connects the console port on the back of
the router to an RJ-45 to DB-9 connector on the back of a PC. This cable ships with the
router.
➢ ROM monitor mode A router mode that allows you to configure your router in the
event that no valid IOS file is in your flash memory.
➢ user EXEC mode A router mode that allows a network operator to check router status,
see if the interfaces are operational, and review several of the router settings.
➢ user mode See user EXEC mode.
➢ virtual terminal password A password that is used to access the router over a telnet
connection.
