© wiley inc. 2006. all rights reserved. chapter 4: introduction to the cisco ios ccna: cisco...

© Wiley Inc. 2006. All Rights Reserved.

CHAPTER 4: Introduction to the

Cisco IOS

CCNA: Cisco Certified Network Associate Study

Guide


The CCNA exam topics covered in this chapter include the following:

Implementation & Operation•Configure IP addresses, subnet masks, and gateway addresses on routers and hosts• Configure a router for additional administrative functionality•Implement a LAN •Perform an initial configuration on a router• Perform an initial configuration on a switch


Cisco Router IOS

• Carries network protocols and functions

• Connects high-speed traffic between devices

• Adds security to control access• Provides scalability for growth• Supplies reliability


Connecting To A Cisco Router


Bringing up a Router

• Boot-up process:1: POST2: Looks for the Cisco IOS from Flash

memory3: IOS loads & looks for a valid configuration;

• startup-configstartup-config• stored in nonvolatile RAM (NVRAM)

4: If a valid config is not found in NVRAM:• setup modesetup mode


Setup Mode

• Basic Management Setup

• Extended Setup

• Command-Line Interface


Command-Line Interface (CLI)

• More flexible than setup mode.• To use the CLI, just say No to

entering the initial configuration dialog.


Logging into the Router

• User mode: – Router>– Used mostly to view statistics

• Privileged mode:– Router#– Used to view & change router configuration


Overview of Router Modes

• Global changes:– config terminal or config t– Changes made to running-config running-config (DRAM)– To change the startup-configstartup-config (NVRAM)

• config memory or config memNote: Any configuration changes need to be placed into RAM. Typing config mem or config net (from a TFTP host) will replace the current running-configrunning-config


Configuration

• CLI Prompts• Interfaces• Sub-interfaces• Line Commands• Routing Protocol

Configurations


Editing & Help Features


Editing & Help Features

• Commands starting with a certain letter

Router#c?clear clock configure connect copy

• Enhanced Editing Commands• Router-Command History• Gathering Basic Routing

Information– show versionshow version


Enhanced Editing Commands


Enhanced Editing Commands (cont.)


Router Command History


Gathering Basic Routing Information


Administrative Functions

The administrative functions that you can configure on a router and switch are

• Hostnames• Banners• Password• Interface descriptions


Hostnames & Descriptions

• HostnamesRouter(config)#hostname toddtodd(config)#

• DescriptionsAtlanta(config)#int e0Atlanta(config-if)#description Sales Lan


Banners

• Purpose• Types

– exec– incoming– login– motd

• Delimiting character


Setting the Passwords

• 5 passwords:– 1st two used to set your enable password

• Used to secure privileged mode; Router>enable

– Other three are used to configure a password in useruser mode via:

• console port• auxiliary port• Telnet


Passwords

• Enable passwordsRouter(config)#enable password ciscoRouter(config)#enable secret cisco

• Auxiliary Password• Console Password• Telnet Password• Encrypting Your Password

Router(config)#service password-encryption


Interface DescriptionsSetting descriptions on an interface is helpful to the administrator and, like the hostname, only locally significant. The description command is a helpful one because you can, for instance, use it to keep track of circuit numbers.

Here’s an example:Atlanta(config)#int e0Atlanta(config-if)#description Sales LanAtlanta(config-if)#int s0Atlanta(config-if)#desc Wan to Miami circuit:6fdda4321

You can view the description of an interface either with the show running-config command or the show interface command.


Router Interfaces• Purpose• Bringing up an Interface

no shutdownshutdownshow interface

• Configuring an IP Address on an Interface

Router(config)#int e0Router(config-if)#ip address

172.16.10.2 255.255.255.0Router(config-if)#no shut

• Serial Interface Commandsclock rate & bandwidth (entered

in kilobits)


Viewing, & Saving Configurations

• Viewing & Saving Configurations– running-configrunning-config saved in DRAM– startup-configstartup-config saved in NVRAM

copy run startsh runsh starterase startup-config


Verifying Your Configuration

Tools:– show running-config– show startup-config– ping– show cdp nei detail– trace– telnet


Other Verification Methods

• Verifying with the show interface command– Router#show interface ?

• Verifying with the show ip interface command– Router#show ip interface– Router#show ip interface brief– Router#show controllers

© wiley inc. 2006. all rights reserved. chapter 4: introduction to the cisco ios ccna: cisco...

Documents