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Introduction to routers


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Introduction to routers

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