1. CCNA2 Chapter 2 Cisco IOS Software

2. Cisco’s operating system is called Cisco Internetwork Operating System (IOS) IOS provides the following network services: basic routing and switching functions reliable and secure access to networked resources network scalability Cisco IOS Software

3. Cisco IOS software uses a command-line interface (CLI) as the console environment. This environment is accessible via: console session Uses a low speed serial connection directly from PC to router AUX port Dialup with a modem through AUX port. Don’t need the router to be connected to network services Telnet Must have at least one interface configured with IP address, and virtual terminal sessions must be configured for login & password. Access to Routers

4. The Cisco CLI uses a hierarchical structure, called modes. The IOS provides a command interpreter service known as the command executive (EXEC). For security reasons, Cisco routers have two access levels: user EXEC mode Has limited number of basic monitoring commands. This mode is identified by > (Example: Router> ) privileged EXEC Requires password May require an user ID Users can accesses all router commands This mode is identified by # (Example: Router# ) Cisco IOS Software

5. Cisco IOS releases naming convention contain 3 parts: platform on which the image runs special features supported in the image where the image runs and whether it has been zipped or compressed It is of the form: xxxx-yyyy-ww xxxx = Platform yyyy = Features ww = Format – where it executes Cisco IOS Software

6. Before installing a new Cisco IOS software image on the router, check to see if the router meets the memory requirements. Use the command: show version Cisco IOS Software

7. To find out amount of flash memory, use the command: show flash Cisco IOS Software

8. show version command displays: IOS version and descriptive information bootstrap ROM version boot ROM version router up time last restart method system image file and location router platform configuration register setting (how IOS is booted) Router Commands

9. IOS version Boot ROM version Router up time Last restart method System image file & location Configuration register setting Number & type of interfaces on the router Platform Feature set Location to be used for loading the IOS

10. This command will show all of the Cisco IOS image files – not just the one that the router booted from. Might compare to a directory listing

11. Cisco IOS has 3 distinct operating environments or modes: ROM monitor Performs the bootstrap process Provides low-level functionality and diagnostics. Used for password recovery. Can NOT be accessed through any interface. Boot ROM Only a limited subset of Cisco IOS features are available. One is allowed to write to flash memory & is used primarily to replace the Cisco IOS image stored in flash Cisco IOS Needs the full IOS image as stored in flash Cisco IOS Software

12. The major steps in initialization of a router are: Power up self test (POST) Bootstrap loader in ROM executes Locate and load the operating system Locate and load the configuration files Initial Startup

13. Bootstrap loader Simple set of instructions that tests hardware and initializes the IOS Locate and load IOS (determined where by the configuration register stored in NVRAM (if indicates Flash, then looks for boot system comands; if none, the default is:) Flash TFTP server ROM locate and load configuration files NVRAM TFTP server Console If no TFTP server is found, then the setup dialog is initiated. Initial Startup

14. Setup mode is not intended to be used to enter complex protocol features in a router. The purpose of the setup mode is to permit administrators to install a basic configuration for routers when a configuration cannot be obtained from another source. In the setup mode, default answers appear in square brackets [ ] following the question. Pressing the Enter key accepts these defaults. During the setup process, Ctrl-C can be pressed at any time to terminate the process. Setup Mode

15. The router will enter setup mode when: – The contents of NVRAM have been erased with the “erase start” command – The router is “out of the box” and has not been initially configured – After deleting the backup configuration and reloading the router You can make the router enter setup mode by entering: – Router#setup Setup Mode

16. After the system initializes correctly, the LED to the right of the AUX port will become green. (2600 light is in the front) Initial Startup

17. The default parameters for the console port are: console port: 9600 baud data bits: 8 no parity 1 stop bit no flow control HyperTerminal

18. User (User EXEC) mode Router> Privilege mode Router# Global configuration mode Router# config t Only accessible from the privilege mode. From this mode one can access: interfaces sub interfaces line router router-map Router Modes

20. ? Ctrl-A – moves to the beginning of the command line Esc-B – move back one word Ctrl-B – move back one character (left arrow) Ctrl-E – move to the end of the command line Ctrl-F – move forward one character (right arrow) Esc-F – move forward one word Ctrl-P – recalls last or previous command (up arrow) Ctrl-N – recalls most recent command (down arrow) - complete the entry Router HELP commands

21. Using the Help System

22. Router HELP commands

23. Maximum number of commands in the history buffer is 256 Router Command History