1 / 44

Routers - PowerPoint PPT Presentation

  • Uploaded on

Routers. A router is a computer Computers have four basic components: a CPU, memory, interfaces, and a bus The router is a computer that selects the best paths, and manages the switching of packets between two different networks. Cisco Routers. Router - internal components. RAM/DRAM

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about ' Routers' - berny

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  • A router is a computer

  • Computers have four basic components:

    • a CPU,

    • memory,

    • interfaces, and

    • a bus

  • The router is a computer that selects the best paths, and manages the switching of packets between two different networks

Router internal components
Router - internal components


    • Stores routing tables, ARP cache, fast-switching cache, packet buffering (shared RAM), and packet hold queues.

    • also provides temporary and/or running memory for the router’s configuration file while the router is powered on.

    • RAM content is lost when you power down or restart.

Router internal components1
Router - internal components


    • non-volatile RAM

    • stores a router’s backup/start-up configuration file;

    • content remains when you power down or restart

Router internal components2
Router - internal components

  • Flash

    • erasable, reprogrammable ROM

    • holds the operating system image and microcode

    • allows you to update software without removing and replacing chips on the processor

    • content remains when you power down or restart

    • multiple versions of IOS software can be stored in Flash memory

Router internal components3
Router - internal components

  • ROM

    • contains power-on diagnostics,

    • a bootstrap program, and

    • operating system software

    • software upgrades in ROM require replacing pluggable chips on the CPU

Router internal components4
Router - internal components

  • Interface

    • network connection through which packets enter and exit a router

    • it can be on the motherboard or on a separate interface module

Router configuration
Router Configuration

  • A router is made up of configurable components.

  • A router has modes

    • examining,

    • maintaining, and

    • changing the components.

Router configuration1
Router Configuration

  • show commands are used for examination.

  • You use cdp to show entries about neighbours.

  • You access other routers by using telnet.

  • You test network connectivity layer by layer.

  • Testing commands include ping, trace, telnet, and debug

Router configuration2
Router Configuration

  • A router can be configured from many locations:

    • Upon initial installation, it is configured from the console terminal. The console terminal is a computer connected to the router through the console port.

    • It can be connected via modem by using the auxiliary port.

    • After it is installed on the network, it can be configured from Virtual Terminals 0 through 4.

  • Files can also be downloaded from a TFTP server on the network

Router modes
Router Modes

  • Whether accessed from the console or by a Telnet session through a TTY port, the router can be placed in several modes.

  • Each mode provides different functions:

    • User EXEC mode

    • Privileged EXEC mode

    • Set-up mode

    • Global configuration mode

    • Other configuration modes

  • RXBOOT mode

Router modes1
Router Modes

  • User EXEC mode

    • A “look-only” mode in which the user can view some information about the router, but cannot change anything.

  • Privileged EXEC mode

    • Supports the debugging and testing commands, detailed examination of the router, manipulation of configuration files, and access to configuration modes.

Router modes2
Router Modes

  • Set-up mode

    • Presents an interactive prompted dialog at the console that helps the new user create a first-time basic configuration.

  • Global configuration mode

    • Implements powerful one-line commands that perform simple configuration tasks.

Router modes3
Router Modes

  • Other configuration modes

    • Provide more detailed multiple-line configurations.

  • RXBOOT mode

    • A maintenance mode that can be used, among other things, to recover lost passwords.

Router status commands
Router Status Commands

  • show version

    • Displays the configuration of the system hardware,

    • the software version,

    • the names and sources of configuration files, and

    • the boot image.

  • show processes

    • Displays information about the active processes.

Router status commands1
Router Status Commands

  • show protocols

    • Displays the configured protocols.

    • This command shows the status of all configured Layer 3 protocols.

  • show mem

    • Shows statistics about the router’s memory, including memory free pool statistics.

Router status commands2
Router Status Commands

  • show stacks

    • Monitors the stack use of processes and interrupt routines and displays the reason for the last system reboot.

  • show buffers

    • Provides statistics for the buffer pools on the router.

  • show flash

    • Shows information about the Flash memory device.

Router status commands3
Router Status Commands

  • show running-config

    • Displays the active configuration file.

  • show startup-config

    • Displays the backup configuration file.

  • show interfaces

    • Displays statistics for all interfaces configured on the router.

Cisco discovery protocol cdp
Cisco Discovery Protocol (CDP)

  • CDP provides a single proprietary command that enables network administrators to access a summary of what the configurations look like on other directly connected routers.

  • CDP runs over a data link layer connecting lower physical media and upper-network-layer protocols.


  • Because CDP operates at this level, CDP devices that support different network-layer protocols can learn about each other.

  • CDP starts up automatically at boot up. CDP can then automatically discover neighbouring Cisco devices running CDP.


  • Discovered devices extend beyond those having TCP/IP.

  • CDP discovers directly connected Cisco devices regardless of which Layer 3 and 4 protocol suite they run.


  • CDP provides information about each CDP neighbour device. Values include the following:

    • Device identifiers—For example, the router’s configured host name and domain name (if any)

    • Address list—At least one address for SNMP, up to one address for each protocol supported

    • Port identifier—Such as Ethernet 0, Ethernet 1, and Serial 0

    • Capabilities list—If, for example, the device acts as a source route bridge as well as a router

    • Version—Information such as that provided by the local command show version

    • Platform—The device’s hardware platform; for example, Cisco 7000

Cisco router configuration
Cisco Router Configuration

  • We have seen

    • show and

    • cdp commands

  • show startup-config - display the backup configuration file

  • show running-config—display active configuration file.

Cisco router configuration1
Cisco Router Configuration

  • erase startup-config - deletes the backup configuration file in NVRAM.

  • reload - reloads the router, causing it to run through the entire configuration process.

  • Setup - to enter setup mode from the privileged EXEC prompt.

Cisco router configuration2
Cisco Router Configuration

  • configure terminal—Configures manually from the console terminal.

  • copy tftp running-config—Loads configuration information from a network TFTP server.

  • copy running-config startup-config— Stores the current configuration from RAM into NVRAM.

Cisco router configuration3
Cisco Router Configuration

  • copy running-config tftp — Stores the current configuration from RAM on a network TFTP server.

Cisco router configuration4
Cisco Router Configuration

Router> enable


Router# configure terminal

Router(config)# [configure mode command]

  • e.g. interface, subinterface, controller, line, router etc.

Cisco router configuration5
Cisco Router Configuration

  • Specific configuration modes:

    • interface mode - for configuring interfaces

    • subinterface mode - for configuring multiple virtual interfaces on a single physical interface

    • line mode - for configuring the operation of a terminal line

    • router mode - for configuring an IP routing protocol

    • etc.

Cisco router configuration6
Cisco Router Configuration

  • Configuring router identification

    Router# config term

    Router(config)# hostname LABA


    ctrl-z : back to privileged exec mode

    exit : back out one level

Cisco router configuration7
Cisco Router Configuration

  • Message of the day banner

    LABA(config)#banner motd # message #

  • Interface description

    LABA(config)#interface ethernet 0

    LABA(config-if)#description my LAN, BG

Password configuration
Password configuration

  • Console password

  • Virtual terminal password

  • Privileged exec password

Console password
Console password

LABA(config)#line console 0


LABA(config-line)#password cisco

Virtual terminal password
Virtual Terminal password

LABA(config)#line vty 0 4


LABA(config-line)#password cisco

  • Enable Password

    LABA(config)#enable password class

    or prefer

    LABA(config)#enable secret class

Configuring interfaces
Configuring interfaces

LABA(config)#int s 0

LABA(config-if)#clock rate 56000

  • clk rate is set for DCEs

    LABA(config-if)#bandwidth 56

  • no clock rate removes clock rate

  • shut down/no shut down

Configuring routing protocols
Configuring routing protocols

LABA(config)#router rip


LABA(config-router)# network



LABA#show ip protocol

LABA#show ip route [routing table]

Configuring routing protocols1
Configuring routing protocols

LABA>show ip interfaces

LABA#debug ip rip

Exercise configuring laba
Exercise - Configuring LABA

  • Hostname:



    Router#config term

    Router(config)#hostname lab-a

Exercise configuring laba1
Exercise - Configuring LABA

  • Enable secret password - class

    lab-a(config)#enable secret class

Exercise configuring laba2
Exercise - Configuring LABA

  • All appropriate interfaces with IP addresses and subnet masks

    lab-a(config)#int s 0

    lab-a(config-if)#ip address

    lab-a(config-if)#clockrate 56000

    lab-a(config-if)#bandwidth 56

Exercise configuring laba3
Exercise - Configuring LABA

lab-a(config)#int e 0

lab-a(config-if)#ip address

lab-a(config-if)#bandwidth 56

lab-a(config)#int e 1

lab-a(config-if)#ip address

lab-a(config-if)#bandwidth 56

Exercise configuring laba4
Exercise - Configuring LABA

  • Configure rip

    lab-a(config)#router rip


    lab-a(config)# network

    lab-a(config)# network

Exercise configuring laba5
Exercise - Configuring LABA

  • Console login password - cisco

    lab-a(config)#line console 0


    lab-a(config-line)#password cisco

Exercise configuring laba6
Exercise - Configuring LABA

  • Vty login password - cisco

    lab-a(config)#line vty 0 4


    lab-a(config-line)#password cisco