Introduction to routers
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Introduction to routers






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Introduction to routers Introduction to routers Presentation Transcript

  • Introduction to Routers Chapter 2
  • Introduction to Routers
    • Objectives:
      • Describe the purpose of the IOS
      • Describe the basic operation of the IOS
      • Identify Features of IOS
      • Identify Methods of Establishing the CLI session with the router
      • Move between the user command executive (EXEC) and Privileged EXEC modes
      • Establish a HyperTerminal Session
      • Log into the Router
      • Use the Help feature in the CLI
      • Troubleshoot Command Errors
  • Operating Cisco IOS Software
    • A router or switch can not function without an operating system.
    • Cisco nternetwork Operating System ( IOS) is the software that controls the Routing and Switching Functions of internetworking devices.
    • It is installed in all Cisco routers and Catalyst switches.
  • The Purpose of the IOS
    • Basic Routing and Switching Functions
    • Reliable and Secure access to Networks Resources.
    • Network Scalability
  • Cisco IOS software features
    • Cisco IOS devices have three operating environments:
      • ROM Monitor
        • To recover from system failures and recover a lost password
      • Boot ROM
        • To modify the Cisco IOS image in Flash
      • Cisco IOS
        • Normal startup
  • Router User Interface
    • Cisco IOS software uses a Command Line Interface (CLI)
    • The CLI environment is accessible
      • Through a console session (No network configuration is required)
      • Dial-up connection
      • Telnet connection as a virtual terminal.
  • Starting a Router
    • Initial startup of Cisco Routers
      • POST
      • Bootstrap is loaded from ROM
      • IOS is loaded from flash, TFTP, RMON
      • Config is loaded from NVRAM or TFTP into setup mode
  • Establish a Console Session
    • To establish a Hyper Terminal Session
      • Connect the terminal with an RJ-45-to-RJ45 Rollover cable or
      • RJ45-to-DB-9 or
      • RJ45-to-DB-25 Adapter
  • Router User Interface
    • The Cisco CLI uses a hierarchical structure.
    • Cisco IOS Software provides a command interpreter service known as EXEC
    • EXEC Access Levels:
      • User EXEC Mode
      • Privileged EXEC mode
  • Router Login
    • User EXEC mode
    • Privileged EXEC mode
  • History Size
    • To change the number of command lines the system records during a terminal session, use the terminal history size or the history size command.
      • The maximum number of commands is 256.
  • Router Interfaces
    • LAN Interfaces – Ethernet, FastEhternet, Token- Ring
    • Router(config)#interface ethernet 0
    • Router(config)#interface fa 0/0
    • Router(config)#interface to 0
    • Router(config-if)#
    • Wide-area Interfaces - Serial, AUX, ISDN BRI
    • Router(config)#interface serial 0
    • Router(config-if)#
    • Logical Interfaces
    • Router(config)#interface serial 0.1
    • Router(config-if)#
  • LAN Interfaces
    • Ethernet
      • Many routers – 15-pin AUI Ethernet interfaces – require an external transceiver
      • The AUI interface is a standard for Cisco 2500 series routers. Some of them have both types – AUI and 10BaseT Ethernet
    • Fast-Ethernet
      • Common interfaces on Cisco routers are RJ45 and the 40-pin DB-40 Media-Independent Interface (MII)
      • 100 Mbps speed, half- and full-duplex
    • Token-Ring
      • Set the ring speed of the interface
      • Connect the token-ring interface to a MAU
  • WAN Interfaces
    • Synchronous Serial Interface
      • Cable types – V.35 or RS-232
      • Configure the proper encapsulation type
      • Use “show controllers” command to check if the interface acts as a DTE or DCE
      • If the interface is acting as a DCE – supply a clock rate
        • Router(config-if)#clock rate 56000
  • Other WAN Interfaces
    • ATM Interfaces
      • Operate at OC-3 speeds and higher
      • Configuring PVCs
    • ISDN Interfaces
      • Two different type of interfaces - the ISDN BRI and ISDN PRI
      • Both interfaces must establish communications with the ISDN switch before passing data
    • Asynchronous Interfaces
      • The AUX (Auxiliary) port on a Cisco router can be configured as an asynchronous port
      • Support dial-in modems
  • Router Interfaces States
    • Interface X is down, line protocol is down
    • Interface X is up, line protocol is down
    • Interface X is up, line protocol is up
    • Interface X is administratively down, line protocol is down
    • The first listing refers to the physical layer status of the interface. To troubleshoot the physical layer issue – show controllers
    • The second listing reflects the data-link status. UP – UP state reflects a successful sending and received keepalives.
  • DTE and DCE interfaces
    • DTE and DCE status is determined by the configuration of the cables attached to the interface.
    • Router#show controllers serial 0
    • …………… V.35 DTE Cable
    • Router#show controllers serial 1
    • …………… .V.35 DCE Cable, clockrate 56000
    • Router#show controllers serial 2
    • …………… , No cable
  • Cable connection
    • Router Ethernet 10BaseT interface to a 10BaseT hub or LAN switch – straight through cable
    • One router Ethernet interface to another router Ethernet interface – crossover cable
    • Direct connection between PC with Ethernet interface to a router Ethernet interface – crossover cable