ccna2 m4 learning about other devices

8/14/2019 CCNA2 M4 Learning About Other Devices

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CCNA Semester2

Module 4

Learning about other devices

Objectives

Cisco Discovery Protocol

Getting information about remote devices


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Discovering and Connecting to

Neighbors

Introduction to CDP

Cisco Discovery Protocol(CDP) is a Layer 2protocol that connectslower physical media andupper network layerprotocols

CDP is used to obtaininformation aboutneighboring devices


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Introduction to CDP

CDP is media and protocol independent, and

runs on all Cisco equipment over the

Subnetwork Access Protocol (SNAP). When a Cisco device boots up, CDP starts up

automatically and allows the device to detect

neighboring devices that are also running CDP.

Information obtained with CDP

CDP provides information about each CDP

neighbor device by transmitting type length

values (TLVs), which are blocks of information

embedded in CDP advertisements.


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Information obtained with CDP

Device TLVs displayed by the show cdp neighborscommand include the following: Device ID

Local Interface Holdtime

Capability

Platform

Port ID

VTP Management Domain Name (CDPv2 only)

Native VLAN (CDPv2 only)

Full/Half-Duplex (CDPv2 only)

CDP Example

Cisco

RouterD


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CDP Commands

Show cdp neighbor detail-------------------------

Device ID: SCA0425051J

Entry address(es):

IP address: 192.168.4.254

Platform: WS-C6509, Capabilities: Trans-Bridge Switch

Interface: FastEthernet0/24, Port ID (outgoing port): 3/20

Holdtime : 138 sec

Version :

WS-C6509 Software, Version McpSW: 5.4(2) NmpSW: 5.4(2)

Copyright (c) 1995-2000 by Cisco Systems

advertisement version: 2

VTP Management Domain: 'SSP'Native VLAN: 20

Duplex: full

-------------------------

Device ID: Switch

Entry address(es):

Platform: cisco WS-C2924-XL, Capabilities: Trans-Bridge Switch

Interface: FastEthernet0/23, Port ID (outgoing port): FastEthernet0/24

Holdtime : 127 sec


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Creating a network map of the environment

CDP was designed and implemented as a simple, low-

overhead protocol.

Though a CDP frame can be small, it can retrieve a great

deal of useful information about connected neighboring

Cisco devices.

Troubleshooting CDP


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Getting Information about

Remote Devices

Telnet

Telnet is a virtual terminal protocol that is partof the TCP/IP protocol suite.

It allows connections to be made to remotehosts. Telnet provides a network terminal orremote login capability.

Telnet is an IOS EXEC command used to verifythe application layersoftware between sourceand destination.

This is the most complete test mechanismavailable.


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Telnet

Telnet functions at theapplication layerof the OSImodel and depends on TCP toguarantee the correct and

orderly delivery of databetween the client and server.

A router can have multiplesimultaneous incoming Telnetsessions. The range 0 through4 is used to specify 5 VTY orTelnet lines for standard IOS.

Establishing a Telnet connection

To initiate a Telnet session any of the following

alternatives can be used:

Denver>connect paris (if DNS available)

Denver#paris

Denver>131.108.100.152

Denver>telnet paris


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Disconnecting Telnet sessions

To terminate a Telnet session any of the

following alternatives can be used:

Denver>disconnect parisDenver>exit

To suspend a Telnet session:

Press Ctrl-Shift-6, then x

To set ideal timeout (default is 10 mins):

(config-line)#exec-timeout minute [second]

Telnet process

LAB_A

LAB_B

Telnet LAB_B

Connect LAB_B

Ctrl-Shift-6 x

Enter

Resume 1

Exit

Disconnect

- Enter key will resume the most recent connection

-The resume is used with connection ID


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Ping

The ping command first sends an echo request packet to an

address, then waits for a reply. The ping is successful only if:

the echo request gets to the destination, and

the destination is able to get an echo reply back to the

source.

Ping Result

A successful echo-reply is expressed with a ! symbol

Echo-reply timeout in 2 seconds (default) is expressed with .Symbol

Change default ping settings with extended ping command

(Router)#ping [Enter]

Use Ctrl-Shift-6 escape sequence stop ping process


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Traceroute

The traceroute command isthe ideal tool for findingwhere data is being sent ina network.

The traceroute command issimilar to the pingcommand, except thatinstead of testing end-to-end connectivity, traceroutetests each step along theway.

asterisk indication meansone router is unreachable

Use Ctrl-Shift-6 escape

sequence stop tracerouteprocess

Trace Process


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Summary

Cisco Discovery Protocol-CDP

Telnet command

Ping command

Traceroute command

Lab Topology

Given access to a running network topology,

find out the following:

How devices are interconnected (physical topology)

Device name, platform

Interface name and address


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CCNA2 Module4

ccna2 m4 learning about other devices

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