1. Institute of Technology Sligo - Dept of Computing Router Components Semester 2 Chapter 4 Paul Flynn

2. Institute of Technology Sligo - Dept of Computing Table of Contents More on Components The Show Command Network Neighbor Routers Basic Network Testing

3. Institute of Technology Sligo - Dept of Computing More on Components  Configuration  Details on RAM  Router Modes Table of Contents

4. Institute of Technology Sligo - Dept of Computing External Configuration  A router can be configured from four separate sources:  Console port (used to initially configure the router)  WAN/LAN links (attach through hub or switch using a patch cable)  Auxiliary port (needs a modem)  TFTP server installed on the network  The easiest place to configure from is the console port.  Attach a rollover cable from the router to your computer COM1 or COM2 port  Open HyperTerminal to log in

5. Institute of Technology Sligo - Dept of Computing Internal Configuration  Review “Router Basics” section in Ch.2/3 Powerpoint. RAMNVRAMFlashROM Interfaces Console Auxiliary

6. Institute of Technology Sligo - Dept of Computing RAMNVRAMFlashROM Interfaces Console Auxiliary As the router is booted, the following is loaded into RAM’s Working Storage. RAM Specifics RAM Command Executive Internetwork Operating System (IOS) Programs Active Config File TablesBuffers

7. Institute of Technology Sligo - Dept of Computing Programs include the bootstrap program that tests the equipment (POST) and locates the IOS. RAM Specifics RAM Programs

8. Institute of Technology Sligo - Dept of Computing RAM Specifics RAM Internetwork Operating System (IOS) Programs Once the IOS is located by the bootstrap program, it is loaded in to RAM.

9. Institute of Technology Sligo - Dept of Computing RAM Specifics RAM Command Executive Internetwork Operating System (IOS) Programs Part of the IOS is the Command EXEC. This is the program that translates the commands you type into a language that the IOS can understand.

10. Institute of Technology Sligo - Dept of Computing RAM Specifics RAM Command Executive Internetwork Operating System (IOS) Programs Active Config File Once the IOS is initialized, it looks for an active configurations file (usually in NVRAM) and loads it. This file tells the router specifically what to do.

11. Institute of Technology Sligo - Dept of Computing RAM Specifics RAM Command Executive Internetwork Operating System (IOS) Programs Active Config File Tables The tables are loaded from the configuration file including... ARP Tables Routing Tables

12. Institute of Technology Sligo - Dept of Computing RAM Specifics RAM Command Executive Internetwork Operating System (IOS) Programs Active Config File TablesBuffers Finally, all leftover memory in RAM is used as the buffer for processing incoming and outgoing packets.

13. Institute of Technology Sligo - Dept of Computing Router Modes Good graphic. Learn it.

14. Institute of Technology Sligo - Dept of Computing The Show Command

15. Institute of Technology Sligo - Dept of Computing Router Status Commands  On the next slide, you will see a graphic displaying the most common show commands.  Be sure to copy this graphic in your notes.  You need to know which component of the router the show command accesses and what each show command displays.

16. Institute of Technology Sligo - Dept of Computing FlashNVRAMRAM Internetwork Operating System Programs Active Configuration File Tables and Buffers Backup Configuration File Operating Systems Interfaces Router#show versionRouter#show flashRouter#show interfaces Router#show processes CPU Router#show protocols Router#show running-config Router#write term Router#show mem Router#show stacks Router#show buffers Router#show startup-config Router#show config

17. Institute of Technology Sligo - Dept of Computing Show Commands Defined  show version -- displays the configuration of the system hardware, the software version, the names and sources of configuration files, and the boot image  show startup-config (show config on Cisco IOS 10.3 or earlier) -- displays the backup configuration file  show flash -- shows information about the Flash memory device  show interfaces -- displays statistics for all interfaces configured on the router  show processes -- displays information about the active processes  show protocols -- displays the configured protocols; shows the status of all configured Layer 3 protocols

18. Institute of Technology Sligo - Dept of Computing Show Commands Defined  show running-config (write term on Cisco IOS 10.3 or earlier) -- displays the active configuration file  show memory -- shows statistics about the router's memory, including memory free pool statistics  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

19. Institute of Technology Sligo - Dept of ComputingLab  Before moving on, make sure you have completed…  Lab 4.2.4-Router show commands

20. Institute of Technology Sligo - Dept of Computing Network Neighbor Routers Table of Contents

21. Institute of Technology Sligo - Dept of ComputingCDP  In order to fully understand how Cisco Discovery Protocol operates, do the lab.  4.3.5-CDP Neighbors

22. Institute of Technology Sligo - Dept of Computing Basic Network Testing Table of Contents

23. Institute of Technology Sligo - Dept of Computing Multiple Testing Methods  For a basic introduction to router troubleshooting, do the labs.  4.4.2-Remote telnet access  4.4.3-ICMP Ping  4.4.4-Traceroute command  4.4.7-Show interfaces & clear counters  4.5.1-Troubleshooting tools challenge  Active mental participation in answering lab questions is crucial to do well on the test.  You will also retain the knowledge longer if you think about what you are doing and why!