Chapter 09 - Managing Cisco IOS

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Chapter 9Managing a Cisco Internetwork


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Objectives

On completion of this chapter, you will be able toperform the following tasks:

The Router Boot Sequence

Managing Configuration Registers

Backing Up and Restoring the Cisco IOS

Backing Up and Restoring the Cisco

ConfigurationUsing Cisco Discovery Protocol (CDP)


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ROUTER BOOT SEQUENCEAND VERIFICATION


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Router Startup Sequence


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How A Cisco Device Locates AndLoads IOS

Configuration register valueThis value is saved in NVRAM and allow modification ofwhere to boot Cisco IOS image

Configure terminalBoot system flash c2600-i-mz

Boot system tftp c2600-jk8o3-mz

boot system commands not found in NVRAM

Get default Cisco IOS software from flash

If flash is empty, get default Cisco IOS from TFTP server


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Using The Boot System Command

Router(config)#boot system flash gsnew-image

Router(config)#boot system tftp gsn-image 1.1.1.1Router(config)# boot system rom

Remember

copy running-config startup-config

The router will execute the boot system commands in the order in which theywere originally entered into configuration mode.


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Configuration Register

Configuration Register Value Description

0xnnn0 Use Rom monitor mode

0xnnn1 Automatically boot from ROM

0xnnn2 0xnnnFExamine NVRAM for boot systemcommands

Router# Show versionRouter(config)#configure-register register-valueEX : boot from flash ,load startup-config

Router(config)#configure-register 0x2102EX : boot from flash and ignore startup-config

Router(config)#configure-register 0x2142


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Troubleshooting IOS Boot Failure

Configuration file has missing or incorrect boot system statementIncorrect configuration register value

Corrupted flash image

Hardware failure


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MANAGING THE CISCO FILE SYSTEM


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wg_ro_a#show flash

System flash directory:

File Length Name/status1 10084696 c2500-js-l_120-3.bin

[10084760 bytes used, 6692456 available, 16777216 total]16384K bytes of processor board System flash (Read ONLY)

Verify that flash memory has room for theCisco IOS image.

Verifying Memory and DecipheringImage Filenames


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Back up current files prior to updating flash memory.

Creating a Software Image Backup


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Upgrading Or Recovering the Imagefrom the Network


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Cisco IOS copy Command

NVRAM

Terminal

TFTP server

Erase start


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DISCOVERING CONNECTEDNEIGHBORS


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Cisco Discovery Protocol

CDP is a proprietary utility that gives you asummary of directly connected switches, routers,

and other Cisco devices. CDP discovers neighboring devices regardless of

which protocol suite they are running.


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Discovering Neighbors with CDP

CDP runs on routers with Cisco IOSsoftware Release 10.3 or later and on Cisco switches and hubs.

Summary information

includes:

Device identifiers

Address list

Port identifier

Capabilities list

Platform


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Using CDP


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Using the show cdpneighbors Command


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Using the show cdp entry Command


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Alternative connectivity tests


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Ping


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SAIGONLAB 69-3 Nguyen Thi Nho, P9, Q.TBinh, Tp. HCM, Tel 08-8655584Website www.sai onlab.com email : info sai onlab.com CCNA A801

Ping command output

Sends ICMP echo packets.

These are the results that may be returned by the ping test:

! successful receipt of an echo reply . timed out waiting for datagram reply

U destination unreachable error

C congestion-experienced packet

I ping interrupted (e.g. Ctrl-Shift-6 X)

? packet type unknown

& packet TTL exceeded


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Trace

Documents

Chapter 09 - Managing Cisco IOS