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Router ComponentsRouter Components

Semester 2Semester 2

Chapter 4Chapter 4Paul Flynn

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Table of ContentsTable of Contents

More on ComponentsMore on Components

The Show CommandThe Show Command

Network Neighbor RoutersNetwork Neighbor Routers

Basic Network TestingBasic Network Testing

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More on ComponentsMore on Components

ConfigurationConfiguration Details on RAMDetails on RAM Router ModesRouter Modes

Table of Contents

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External ConfigurationExternal Configuration A router can be configured from four separate sources:A router can be configured from four separate sources:

Console port (used to Console port (used to initiallyinitially configure the router) configure the router) WAN/LAN links (attach through hub or switch using a patch WAN/LAN links (attach through hub or switch using a patch

cable)cable) Auxiliary port (needs a Auxiliary port (needs a modemmodem)) TFTP server installed on the networkTFTP server installed on the network

The easiest place to configure from is the console port.The easiest place to configure from is the console port. Attach a rollover cable from the router to your computer Attach a rollover cable from the router to your computer

COM1 or COM2 portCOM1 or COM2 port Open HyperTerminal to log inOpen HyperTerminal to log in

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Internal ConfigurationInternal Configuration Review “Router Basics” section in Ch.2/3 Review “Router Basics” section in Ch.2/3

Powerpoint.Powerpoint.

RAM NVRAM Flash ROM

InterfacesConsoleAuxiliary

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RAM NVRAM Flash ROM

InterfacesConsoleAuxiliary

As the router is booted, the following is loaded into RAM’s Working Storage.

RAM SpecificsRAM Specifics

RAMCommandExecutive

InternetworkOperating

System(IOS)

ProgramsActiveConfig

FileTables Buffers

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Programs include the bootstrap program that • tests the equipment (POST) • and locates the IOS.

RAM SpecificsRAM Specifics

RAMPrograms

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RAM SpecificsRAM Specifics

RAMInternetwork

OperatingSystem(IOS)

Programs

Once the IOS is located by the bootstrap program, it is loaded in to RAM.

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RAM SpecificsRAM Specifics

RAMCommandExecutive

InternetworkOperating

System(IOS)

Programs

Part of the IOS is the Command EXEC. This is the program that translates the commands you type into a language that the IOS can understand.

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RAM SpecificsRAM Specifics

RAMCommandExecutive

InternetworkOperating

System(IOS)

ProgramsActiveConfig

File

Once the IOS is initialized, it looks for an active configurations file (usually in NVRAM) and loads it. This file tells the router specifically what to do.

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RAM SpecificsRAM Specifics

RAMCommandExecutive

InternetworkOperating

System(IOS)

ProgramsActiveConfig

FileTables

The tables are loaded from the configuration file including...• ARP Tables• Routing Tables

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RAM SpecificsRAM Specifics

RAMCommandExecutive

InternetworkOperating

System(IOS)

ProgramsActiveConfig

FileTables Buffers

Finally, all leftover memory in RAM is used as the buffer for processing incoming and outgoing packets.

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Router ModesRouter ModesGood graphic. Learn it.

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The Show CommandThe Show Command

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Router Status CommandsRouter Status Commands

On the next slide, you will see a graphic On the next slide, you will see a graphic displaying the most common show displaying the most common show commands.commands.

Be sure to copy this graphic in your notes.Be sure to copy this graphic in your notes. You need to know which component of the You need to know which component of the

router the show command accesses and router the show command accesses and what each show command displays.what each show command displays.

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FlashNVRAMRAM

Internetwork Operating System

ProgramsActive

ConfigurationFile

Tablesand

Buffers

BackupConfiguration

File

OperatingSystems

Inte

rface

sRouter#show version Router#show flash

Router#show interfaces

Router#show processes CPURouter#show protocols

Router#show running-configRouter#write term

Router#show memRouter#show stacksRouter#show buffers

Router#show startup-configRouter#show config

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Show Commands DefinedShow Commands Defined show versionshow version -- displays the configuration of the system -- displays the configuration of the system hardware, the software version, the names and sources of hardware, the software version, the names and sources of configuration files, and the boot image configuration files, and the boot image

show startup-configshow startup-config ( (show configshow config on Cisco IOS 10.3 or on Cisco IOS 10.3 or earlier) -- displays the backup configuration fileearlier) -- displays the backup configuration file

show flashshow flash -- shows information about the Flash memory -- shows information about the Flash memory device device

show interfacesshow interfaces -- displays statistics for all interfaces -- displays statistics for all interfaces configured on the router configured on the router

show processesshow processes -- displays information about the active -- displays information about the active processes processes

show protocolsshow protocols -- displays the configured protocols; -- displays the configured protocols; shows the status of all configured Layer 3 protocols shows the status of all configured Layer 3 protocols

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Show Commands DefinedShow Commands Defined show running-configshow running-config ( (write termwrite term on Cisco IOS 10.3 or on Cisco IOS 10.3 or

earlier) -- displays the active configuration file earlier) -- displays the active configuration file

show memoryshow memory -- shows statistics about the router's -- shows statistics about the router's memory, including memory free pool statistics memory, including memory free pool statistics

show stacksshow stacks -- monitors the stack use of processes -- monitors the stack use of processes and interrupt routines and displays the reason for the last and interrupt routines and displays the reason for the last system reboot system reboot

show buffersshow buffers -- provides statistics for the buffer pools -- provides statistics for the buffer pools on the router on the router

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LabLab

Before moving on, make sure you have Before moving on, make sure you have completed…completed… Lab 4.2.4-Router show commandsLab 4.2.4-Router show commands

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Network Neighbor RoutersNetwork Neighbor Routers

Table of Contents

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CDPCDP

In order to fully understand how Cisco In order to fully understand how Cisco Discovery Protocol operates, do the lab.Discovery Protocol operates, do the lab. 4.3.5-CDP Neighbors4.3.5-CDP Neighbors

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Basic Network TestingBasic Network Testing

Table of Contents

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Multiple Testing MethodsMultiple Testing Methods For a basic introduction to router troubleshooting, do For a basic introduction to router troubleshooting, do

the labs.the labs. 4.4.2-Remote telnet access4.4.2-Remote telnet access 4.4.3-ICMP Ping4.4.3-ICMP Ping 4.4.4-Traceroute command4.4.4-Traceroute command 4.4.7-Show interfaces & clear counters4.4.7-Show interfaces & clear counters 4.5.1-Troubleshooting tools challenge4.5.1-Troubleshooting tools challenge

Active mental participation in answering lab Active mental participation in answering lab questions is crucial to do well on the test. questions is crucial to do well on the test.

You will also retain the knowledge longer if you think You will also retain the knowledge longer if you think about what you are doing and why!about what you are doing and why!