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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

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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