Ch11 1st Config Step

© 2007 Cisco Systems, Inc. All rights reserved. Cisco PublicITE PC v4.0Chapter 1 1

Configuring and Testing Your Network

Network Fundamentals – Chapter 11

ITE PC v4.0Chapter 1 2© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public

Objectives

1. Router Initialization.

2. Router Access

3. CLI First look

4. Basic configuration

5. Viewing, Saving and Erasing the Configurations

6. Discovering & testing the network

7. Remote access (TELNET)


Router Initialization


Router is typically like a computer which operates with

Two main components

–Hardware (Router physical components )

–Software (IOS)

• Internetworking operating system.

• configuration file

Router components


Router external connections


Management Ports

Console port - Most common of the management ports

Used to connect a terminal,

Or most likely a PC running terminal emulator software,

No need for network access to that router.

The console port must be used during initial configuration of the router.

Auxiliary (AUX) port

Not all routers have auxiliary ports.

At times, can be used similarly to a console port

Can also be used to attach a modem.

Note: Auxiliary ports will not be used in this curriculum.


Router Interfaces

Interface on Cisco routers refers to a physical connector on the router whose main purpose is to receive and forward packets.

Routers have multiple interfaces used to connect to multiple networks which may mean:

Various types of networks

Different types of media and connectors.

Different types of interfaces.

For example, Fast Ethernet interfaces for connections to different LANs and also have different types of WAN interfaces used to connect a variety of serial links, including T1, DSL, and ISDN.


LAN Interfaces

Ethernet and Fast Ethernet interfaces.

Used to connect the router to the LAN, similar to how a PC’s Ethernet NIC.

Layer 2 MAC address

Participates in the Ethernet LAN the same way as any other hosts on that LAN.

Example: Address Resolution Protocol (ARP):

Maintains ARP cache for that interface

Sends ARP requests when needed

Responds with ARP replies when required

Typically an RJ-45 jack (UTP).

Router to switch: straight-through cable.

Router to router via Ethernet interfaces, or PC’s NIC to router’s Ethernet interface: crossover cable.


WAN Interfaces

Example: serial, ISDN, and Frame Relay interfaces.

Used to connect routers to external networks, usually over a larger geographical distance.

The Layer 2 encapsulation can be different types including:

PPP

Frame Relay

HDLC (High-Level Data Link Control).

Similar to LAN interfaces, each WAN interface has its own IP address and subnet mask, making it a member of a specific network.

Note: MAC addresses are used only on Ethernet interfaces and are not on WAN interfaces.

However, WAN interfaces use their own Layer 2 addresses depending on the technology.

Layer 2 WAN encapsulation types and addresses are covered in a later course.


Serial Connectors

Cisco routers support the EIA/TIA-232, EIA/TIA-449, V.35, X.21, and EIA/TIA-530 standards for serial connections,

Memorizing these connection types is not important.

Just know that a router has a DB-60 port that can support five different cabling standards.


Serial Connectors

Router is typically a DTE device.

The DTE cable is connected to the serial interface on the router to a CSU/DSU device (DCE).

DTE Cable

DCE Cable


Physically Connecting a WAN Interface

Typically, the router is the DTE device and is connected to a CSU/DSU, which is the DCE device.

Serial interfaces require a clock signal to control the timing of the communications.

In most environments, the service provider (a DCE device such as a CSU/DSU) will provide the clock.

By default, Cisco routers are DTE devices


Serial Connectors

In our labs we will use serial DTE/DCE cables (no CSU/DSU) with a DTE cable connected to one router and a DCE cable connected to the other router.


Cisco Software components

• Cisco IOS (Internetwork Operating System) It is the operating system that manages the hardware platform it is working on.

• Configuration File It is a program file that contains commands that reflect how the router will react.


Router memory

Memory content

ROM storing startup diagnostic code

POST

(Bootstrap program).

RAM holds the running configuration and routing table information

NVRAM store the startup configuration file.

FLASH full Cisco IOS software images.


Step in Router Initialization


Bootup ProcessStep 1: POST (Power On Self Test)

Executes diagnostics from ROM on several hardware components, including the CPU,RAM, NVRAM

Step 2: Loading Bootstrap Program

Copied from ROM into RAM

Executed by CPU

Main task is to locate the Cisco IOS and load it into RAM

Step 3: Locating the IOS

Typically stored in flash memory, but it can be stored in other places such as a TFTP server.

If a full IOS image cannot be located, a scaled-down version of the IOS is copied from ROM

This version of IOS is used to help diagnose any problems and to try to load a complete version of the IOS into RAM.


Boot up Process

Step 4: Loading the IOS Some of the older Cisco routers ran the IOS directly from flash Current models copy the IOS into RAM for execution Might see a string of pound signs (#) while the image

decompresses.

Step 5: Locating the Config File Bootstrap program searches for the startup configuration file

(startup-config), in NVRAM. This file has the previously saved configuration commands and

parameters,

Step 6: Loading the Config File If a startup configuration file is found in NVRAM, the IOS loads it

into RAM as the running-config file and executes the commands. If the startup configuration file cannot be located, prompt the user

to enter setup mode


SECTION SUMMARY

1. Router hardware components

2. Cisco Software components

3. Router memory

4. Router Initialization Steps.


Router Access


ROUTER ACCESS METHODS

Directly using the console portNo configuration needed on the router

Telnet – over the networkNetwork connection

Network configuration on both ends (IP address, subnet mask, etc.)

Telnet password configured on router

Modem (AUX.PORT on the router)

Web access


Console The console port is a management port that provides out-of-band access to a

router.

Examples of console use are:

–The initial configuration of the network device

–Disaster recovery procedures and troubleshooting where remote access is not possible

–Password recovery procedures


AUXILIARY


Using HyperTerminal

Match serial port on PC

Settings


Telnet and SSH

Unlike the console connection, Telnet sessions require active networking services on the device.

A host with a Telnet client can access the z sessions running on the Cisco device.

The Secure Shell (SSH) protocol is a more secure method for remote device access.

SSH client software is not provided by default on all computer operating systems.


Setup mode -Permit the administrator to install a minimal configuration for a router

( appeared if no saved configuration , Ctrl-C to skip )


Setup Mode

The router will enter setup mode when:

The contents of NVRAM have been erased with the “erase start” command

When the router is “out of the box” and has not been initially configured

After deleting the backup configuration and reloading the router

You can make the router enter setup mode by entering:

Router#setup


1. ROUTER ACCESS METHODS

Console , AUXILIARY , TELNET , WEB ACCESS

2. Using HyperTerminal

3. Telnet and SSH

4. Setup mode

SECTION SUMMARY


CLI First look


exit

end

ROUTER Modes


User EXEC Mode

The user EXEC mode allows only a limited number of basic monitoring commands.

This is often referred to as a view only mode.

The user EXEC level does not allow any commands that might change the configuration of the router.

The user EXEC mode can be identified by the > prompt.


Privileged EXEC Mode

The privileged EXEC mode provides access to all router commands.

This mode can be configured to require a password.

Configuration and management commands require that the network administrator be at the privileged EXEC level.

Global configuration mode and all other more specific configuration modes can only be reached from the privileged EXEC mode.

The privileged EXEC mode can be identified by the # prompt.


Moving between the User EXEC and Privileged EXEC Modes


11.1.5 Using CLI help Identify the types of help and feedback available while

using IOS and use these features to get help, take shortcuts and ascertain success


11.1.5 Using CLI help


Abbreviated commands (Router and Switch)

Router# sh inter

Same as

Router# show interfaces


11.1.6 IOS "examination" commands Identify the purpose of the show command and several

of its variations


This command will show all of the Cisco IOS image files – not just the one that the router booted from.

Might compare to a directory listing


IOS software and features The naming convention for the different Cisco IOS releases

contains three parts:

–The platform on which the image runs

–The special features supported in the image

–Where the image runs and whether it has been zipped or compressed


show version Command

IOS version

Number & type of interfaces on the routerNVRAM SPACE

FLASH SPACEConfiguration register setting

Router up time

Last restart method

System image file & location


show version Command


Verify the router boot-up process


Editing Commands

<Ctrl><A> Move to beginning of line

<Ctrl><E> Move to the end of the line

<Esc><B> Move back one word

<Ctrl><F> Move forward one character

<Ctrl><B> Move back on character

<Esc><F> Move forward one word

$ Sign means that the line has scrolled to the left

To disable enhanced editing mode, type terminal no editing at the privileged EXEC mode prompt.


1. Router modes

2. Moving between Modes

3. Basic IOS command structure & CLI help

4. IOS "examination" commands

show version Command, show flash

5. IOS loading control

6. Editing Commands

7. Router Command History

SECTION SUMMARY


Basic configuration


CLI Configuration

Basic Router Configuration:Naming the router

Setting passwords

Configuring interfaces

Configuring a banner

Saving changes on a router

Verifying basic configuration and router operations


Configuring Router Identification


Configuring a Router Password


11.2.4 Configuring Interfaces Identify the role of a router in a network.


Configuring Interfaces

Router#config tRouterA(config)# interface serial 0/0RouterA(config-if)# ip address 192.168.1.1 255.255.255.0RouterA(config-if)# no shutdownRouterA(config-if)# clock rate 56000 (required for serial DCE only)RouterA(config-if)# bandwidth 64 (a value in kbps)RouterA(config-if)# exit

RouterB(config)# int serial 0/1 RouterB(config-if)# ip address 192.168.1.2 255.255.255.252RouterB(config-if)# no shutdownRouterB(config-if)# exitRouterB(config)# exitRouter#To know which interface is the DCE :RouterA# show controller s0/0

S0/0S0/1

192.168.1.1/30192.168.1.2/30


How can you tell which end is the DTE and which end is the DCE? Look at the label on the cable. Look at the connecter between the two cables - The DTE cable will

always be male and the DCE cable will always be female.

DTE Cable DCE Cable

Configuring a serial interface


• Shows the cable type of serial cables

Serial Interface show controller Command


Interfaces

Router#show ip interface briefInterface IP-Address OK? Method Status Protocol

FastEthernet0/0 unassigned YES unset administratively down down

Serial0/0 unassigned YES unset administratively down down

BRI0/0 unassigned YES unset administratively down down

BRI0/0:1 unassigned YES unset administratively down down

BRI0/0:2 unassigned YES unset administratively down down

Serial0/1 unassigned YES unset administratively down down

Router#


Interpreting the Interface Status

Layer 1 status Layer 2 status

- Serial0/1 is administratively down , line protocol is down

interface is shut down

-Serial0/1 is down , line protocol is down

interface or cable H/W failure ( no keep-alives )

-Serial0/1 is up , line protocol is down

different encapsulation type ( PPP , HDLC , FR ) or no clock rate on the DCE device.

Interface is working properly

Other interface status:

S0/1 S0/0


Basic Switch configuration


Managing Console Input

Router(config)#line console 0

Router(config-line)#logging synchronous

Router(config-line)#exec-timeout 0 0

Router(config-line)#exit

Router(config)#no ip domain-lookup


1. Configuring Router Identification

2. Configuring a Router Password

3. Configuring Interfaces

4. Basic Switch configuration

SECTION SUMMARY


Viewing, Saving and Erasing the

Configurations


running-configRouter#show running-config

Current configuration : 542 bytes

!

version 12.2

!

interface FastEthernet0/0

no ip address

shutdown

duplex auto

speed auto

!

interface Serial0/0

no ip address

shutdown

!

line con 0

line aux 0

line vty 0 4

!

end

Router#

The running-config file is the configuration in RAM memory.

All changes are made to the running-config file.

This is the configuration that the router is currently using.

The running-config is lost when the router loses power or reloads.

Privilege mode command.


startup-configRouter#show startup-config

startup-config is not present

Router#

The startup-config file is the saved configuration in NVRAM.

If there is a startup-config file in NVRAM when the router boots up, this file will be copied into running-config.

The running-config is what the router will use.



Copy running-config to startup-config

Router#copy running-config startup-configDestination filename [startup-config]? <Press Enter>

Building configuration...

[OK]

Router#show startup-config

Current configuration : 542 bytes

!

version 12.2

!

interface FastEthernet0/0

<text omitted>


Erase startup-config

Router#erase startup-config

Erasing the nvram filesystem will remove all files! Continue? [confirm] <Press Enter>

[OK]

Erase of nvram: complete

Router#

When you are done with the routers in the lab, please be sure to erase the startup-config.

If you are starting a lab, and you do not get the message:

Would you like to enter the initial configuration dialog? [yes/no]:

You will need to erase the startup-config and reboot.



Cisco IOS copy Command

#

#

#

#

#

#

To save IOS image or configuration file


11.2.3 Managing configuration files Use a text file to backup and restore config settings


Return the Device to Its Original Configuration

Router#reload

System configuration has been modified. Save? [yes/no]: n

Proceed with reload? [confirm]

To erase the startup configuration file use erase NVRAM:startup-config or erase startup-config at the privileged EXEC mode prompt:

Router#erase startup-config


Discovering & testing the network


Cisco Discovery Protocol (CDP)

Cisco Discovery Protocol (CDP) is a powerful network-monitoring and –troubleshooting tool.

CDP is an information-gathering tool used by network administrators to get information about directly connected Cisco devices.

CDP is a proprietary tool that enables you to access a summary of protocol and address information about Cisco devices that are directly connected.


By default, each Cisco device sends periodic messages to directly connected Cisco devices.

These messages are known as CDP advertisements.

A Cisco device frequently has other Cisco devices as neighbors on the network.

Information gathered from other devices can assist you:

in making network design decisions

in troubleshooting

in making changes to equipment.

CDP can be used as a network discovery tool

CDP Advertisements


Layer 2 Neighbors

CDP operates at Layer 2 only.

Therefore, CDP neighbors are Cisco devices that are directly connected physically and share the same data link.

R1 ,S1, R2 are CDP neighbors

R2 , R1 , S2, R3 are CDP neighbors

R3 ,R2 S3 are CDP neighbors


Discovering Neighbors with CDP CDP runs on routers with Cisco IOS

to get information about the direct connected Cisco devices.

Summary information includes:

Device identifiers

Address list

Port identifier

Capabilities list

Platform


Using the show cdp neighbors Command

RouterA# show cdp neighbors detail

provide also the neighbors ip addresses.


SH CDP Neighbor detail Cairo# sh cdp entry -------- Device ID: tanta Entry address(es): IP address : 192.168.2.1 Platform: cisco C2800, Capabilities: Router Interface: FastEthernet0/0, Port ID (outgoing port): FastEthernet0/1 Hold time: 155

Version : Cisco IOS Software, 2800 Software (C2800NM-IPBASE-M), Version

12.3(14)T7, RELEASE SOFTWARE (fc2)

advertisement version: 2 Duplex: full ---------------------------


Enabling CDP on a RouterTo enable CDP, use the cdp run global configuration command. CDP is on by default. Use the no form of this command to disable CDP.

Router(config)#cdp run

To enable Cisco Discovery Protocol (CDP) on an interface, use the cdp enable interface configuration command. Use the no form of this command to disable CDP on an interface. CDP is enabled by default on all supported interfaces.

Router(config)#interface serial 0/0 Router(config-if)#cdp enable


Using the ping and trace Commands

Ping commands tests the connectivity and path to a remote device

( test layer 3 in TCP/IP )


IOS Ping Indicators

A ping from the IOS will yield to one of several indications for each ICMP echo that was sent. The most common indicators are:

–! - indicates receipt of an ICMP echo reply

–. - indicates a timed out while waiting for a reply

–U - an ICMP unreachable message was received

the ping command moves from Layer 3 of the OSI model to Layer 2 and then Layer 1. Ping uses the ICMP protocol to check for connectivity.


11.3.3 Testing the Local Network

Router#ping

Protocol [ip]:

Target IP address:10.0.0.1

Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]:5

Extended commands [n]: n


TELNET


To initiate a Telnet session any of the following alternatives can be used:

Denver>connect paris

Denver>paris

Denver>131.108.100.152

Denver>telnet 131.108.100.152

Denver>telnet paris


Using Telnet to Connect to Remote Devices

Telnet is used to check all the TCP/IP stack


Viewing Telnet Connections


Suspending and Resuminga Telnet Session


Closing a Telnet Session


Summary

1. Router Initialization.

2. Router Access

3. CLI First look

4. Basic configuration

5. Viewing, Saving and Erasing the Configurations

6. Discovering & testing the network

7. TELNET

Ch11 1st Config Step

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