configuring network devices - aoi...

Version 4.1

Configuring Network Devices

Objectives

• Configure a router with an initial configuration.

• Use Cisco SDM to configure a Cisco ISR with LAN connectivity, Internet connectivity and NAT.

• Configure a Cisco router for LAN connectivity, Internet connectivity and NAT using the Cisco IOS CLI.

• Configure a WAN connection from customer premises to an ISP.

• Describe, setup and configure a standalone LAN switch.

Initial ISR Router Configuration• ISR (Integrated Services Router combines routing, LAN

switching, security, voice, & WAN connectivity features.

• Ideal for small to medium-sized businesses & ISP

managed customers.

Initial ISR Router Configuration• Cisco IOS – offered in modules called images

• IP Base image: entry-level Cisco IOS

• Images are specific to models of devices

Cisco 1841 Modular routerTable 1 Memory Requirements for Cisco 1841 Modular Router

Platform Feature Set

Flash RAM

Image Memory1 Memory

Cisco 1841 IP Base c1841-ipbase-mz 64 MB 128 MB

IP Voice c1841-ipvoice-mz 64 MB 192 MB

Enterprise Base c1841-entbase-mz 32 MB 128 MB

Advanced Security c1841-advsecurityk9-

mz

64 MB 192 MB

SP Services c1841-spservicesk9-mz 64 MB 192 MB

Enterprise Services c1841-entservicesk9-

mz

64 MB 192 MB

Advanced IP

Services

c1841-advipservicesk9-

mz

64 MB 192 MB

Advanced Enterprise

Services

c1841-adventerprisek9-

mz

64 MB 192 MB

CISCO IOS Image: Types of Images• Two main types of image your router may use:

1. System image - complete Cisco IOS software. This image is loaded when your router boots and is used most of the time.

– On most platforms, the image is located in Flash memory.

2. Boot image - A subset of the Cisco IOS software. This image is used to perform network booting or to load Cisco IOS images onto the router. This image is also used if the router cannot find a valid system image. Depending on your platform, this image may be called xboot image, rxbootimage, bootstrap image, or boot loader/helper image.

• On some platforms, the boot image is contained in ROM. In others, the boot image can be stored in Flash memory. On these platforms, you can specify which image should be used as the boot image using the boot bootldr global configuration command. Refer to your hardware documentation for information about the boot image used on your router.

Image Naming Convention

• You can identify the platform, features and

image location by the image name.

• Naming convention is: platform – features –

type

• Example: c2600-js-l_121-3.bin• c2600 - hardware platform

• js - features set (enterprise)

• l - file format (relocatable, not compressed)

• 121-3 - version & release # (version 12.1 release 3)

Image Naming Convention - continued

• Platform – variable platform that can use image

– For example c1700, c2600, c7000

• Features –feature sets supported by image.

• Type – can contain following characters

• f—The image runs from Flash memory.

• • m—The image runs from RAM.

• • r—The image runs from ROM.

• • l—The image is relocatable.

• • z—The image is zip compressed.

• • x—The image is mzip compressed.

Initial ISR Router Configuration• Tools and equipment required for setup:

Initial ISR Router ConfigurationThree-stage bootup process:

• Power-on self test (POST)

• Locate and load Cisco IOS

• Locate startup configuration file or enter setup mode

Bootup Process - contd

• POST (Power On Self Test) – test hardware

• After POST, the bootstrap program is loaded

• Bootstrap locates IOS and loads it into RAM

– IOS can be located – flash memory, TFTP server,

or another location

– By default, IOS loads from flash

• After IOS is loaded, bootstrap locates startup

configuration file in NVRAM (non-volatile random

access memory)

• Startup configuration – when loaded into RAM

(working memory), it become the “running”

configuration.

Loading Cisco IOS

Get default IOS from FLASH

Flash empty

Get IOS from TFTP Server

TFTP Server empty

Get limited Cisco IOS from ROM

Show version command output

• Router>show version

• IOS version

• Bootstrap program stored in ROM

• Complete filename of IOS

• Type of CPU; amount of RAM

• Number & type of interfaces

• Amount of NVRAM (used to store startup config)

• Amount of Flash (used to store IOS

• Configuration register in hex

Configuration register

• Default setting – 0x2102 (remember this?)

– Loads IOS from flash

– Loads startup-config from NVRAM

• Most common settings

• 0x2142 –ignores contents of NVRAM/configuration

• 0x2120 – The router into ROMmon mode

• http://www.cisco.com/en/US/products/hw/routers/ps13

3/products_tech_note09186a008022493f.shtml

– **Go to Configuration Register Values & Their

Meaning.

http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a008022493f.shtml

http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a008022493f.shtml

Initial ISR Router Configuration

Verifying and troubleshooting bootup process:

• View output from the show version command

• Use dir flash: and boot flash: in ROMmon mode

• View boot system commands [see miage below on next slide]

Initial ISR Router Configuration (continued)


• Out-of-band management for initial configuration

• In-band management over a network connection

In-Band Out-of-Band

HTTP or Telnet

Terminal emulation


• Command Line Interface (CLI): text-

based program

• Can be used in both in-band or out-of-

band

• Extensive help system [see image below

on next slide]

SDM

• Security Device Manager (SDM): web-based

GUI

• In-Band only

• SDM Express (Basic) or Full package

(Advanced configuration)

• Comes preinstalled in flash

CLI vs. SDM

CLI SDM

User Interface Term Emulation software Web-based browser

Telnet

Configuration Method Text-based Cisco commands GUI buttons & text boxes

Expertise in Cisco Device Config.

Depends on the config task Do not need knowledge of CLI commands

Help Features Command-prompt based GUI based online help & tutorials

Flash Requirements Covered by IOS requirements 6MB of free memory

Availability ALL Cisco devices Cisco 830 series thru Cisco 7301

What It’s Used When device does not support SDM

Initial config of SDM equipped device

Using Cisco SDM Express and

SDM• Follow best practices for installing a new

device to ensure correct functions


SDMEight SDM Express configuration screens:

• Overview

• Basic configuration

• LAN IP address

• DHCP

• Internet (WAN)

• Firewall

• Security settings

• Summary


SDM• Use Basic NAT Wizard to configure dynamic

NAT with PAT

Configuring a Router Using IOS

CLI• CLI command modes: two levels of access


CLI• Configuration modes can alter the operation of

the device


CLI

Help features:

• Command completion

• Error indicators

• Command history

– Enabled by default

– Records 10 command

– Max 256 commands

– history size command

• Arrow and function keys


CLI

• Show commands

display

configuration and

operation

information• R#show run

• R#show

interfaces

• R#show ip route

• R#show protocols


CLI• Use Cisco IOS CLI to perform an initial router

configuration


CLI• Configure serial and Ethernet interfaces on a

router

(DTE) Data Terminal Equipment endpoint of user’s device on the WAN link; Cisco routers

(DCE) Data Communications Equipment; provides clock rate; modem; converts data from router to acceptable format to cross the WAN

If back-to-back router scenario, one of the routers will be DCE and one DTE.


CLI• Configure a default route for the Cisco

router

• Default route used when router does not

know where to send a packet.IP address of

next-hop router

Or

port number


CLI• Configure a Cisco router to function as a

DHCP server


CLI• Configure static NAT on a Cisco router to

enable Internet access for an internal server


CLI• Back up and restore configuration files using a

TFTP server


CLI• Capture and save configuration file output from

a terminal session

Connecting the CPE to the ISP

• Customer Premise Equipment (CPE) – network devices installed

at customer location.

• Configuration checklists ensure that all configuration

requirements are met


• Use inventory and configuration checklists and

an installation plan to ensure successful

installation


• Documentation includes diagrams, checklists,

and activity logs


Types of customer connections over a WAN:

• Point-to-point: often called leased lines;

typically most expensive; price based on

bandwidth & distance between 2 points

• Circuit-switched – similar to a phone call made

over a phone network; example is ISDN or

dialup connection; physical circuit reserved

from source to destination

• Packet-switched – each customer has a virtual

circuit; example is Frame Relay

Customer Connections over

WAN• Bandwidth and cost influence WAN choices


• Clock rate and serial encapsulation are needed when configuring serial

WAN connections

– Clock rate is set by DCE

– DTE accepts clock rate

• Leased WAN connections use serial connection & require Channel

Service Unit/Data Service Unit (CSU/DSU

DCE

DTE

Initial Cisco 2960 Switch

Configuration • Fixed-configuration, standalone devices – does not use modules or flash

card slots. Physical configuration can’t be changed.

• Layer 2 device that directs stream of message coming in from one port,

our of another based on destination MAC address.

• Configured using GUI or CLI

Cisco 2960 switch

• Comes preconfigured

• Needs to be assigned basic security info

• Basic commands (ex: hostname,

passwords) sames as ISR switch.

• Configure management IP address

• One virtual local area network, VLAN 1 is

preconfigured to provide access to

management functions.


Configuration• Switch settings can be configured using the

Cisco IOS CLI

• Assign an IP address to the default

management virtual local area network,

VLAN1


Configuration• Check switch components

• Connect cables to the switch

• Power up the switch and observe POST


Configuration• Connect the stand-alone LAN switch to the

router and verify connectivity

• Configure port security to prevent

unauthorized use

• Shut down unused ports

Switch port security

• Port security limits the # of MAC addresses allowed per port.• Set port to access mode using switchport mode access

command• 3 ways to configure port security:• Static – MAC addresses are manually assigned using

switchport port-security mac-address [mac-address] interface config command.

– S1# configure terminal– S1(config-if)#interface fastethernet 0/20– S1(config-if)#switchport mode access– S1(config-if)#switchport port-security mac-address 1000.2000.3000– S1(config-if)#end–

•

Switch port - contd

• Dynamic MAC addresses are dynamically learned & stored in address table

• # of addresses stored can be controlled; default is one address.

• If port is shut down or switch is restarted, address learned are cleared from the table

S1# configure terminal– S1(config-if)#interface fastethernet 0/20– S1(config-if)#switchport mode access– S1(config-if)#switchport port-security– S1(config-if)#end

Switch port - contd

• Sticky – similar to dynamic

• Addresses learned are saved to the

running-config– S1# configure terminal– S1(config-if)#interface fastethernet 0/20– S1(config-if)#switchport mode access– S1(config-if)#switchport port-security– S1(config-if)#switchport port-security maximum 50– S1(config-if)#switchport port-security mac-address sticky– S1(config-if)#end


Configuration• Cisco Discovery Protocol (CDP) gathers

information about directly-connected Cisco

network devices

• Two Cisco devices directly connected on the

same local network are called neighbors

Summary

• The Integrated Services Router (ISR) is a good choice for small to medium businesses and ISP-managed customers.

• ISRs can be initially configured using SDM or the router IOS CLI.

• When using the CLI, ―show‖ commands verify configuration elements.

• An installation plan can minimize disruption to a network when new devices are being added.

• Documentation is necessary, both when

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