Cisco IOS Management

This chapter introduces the command-line interface (CLI) and presents you with enough information to configure those switch features that require you to use the CLI.

This chapter is an introduction to Cisco IOS. The Catalyst 2900 Series XL Command Reference is a complete description of commands that have been created or changed for the Catalyst 2900 series switches. The documentation set for Cisco IOS Release 11.2(8) describes all commands supported by the switches.

This chapter presents the following topics:

• Using the Catalyst 2900 series XL commands

• Working with files in Flash memory

• Understanding the CLI and its different command modes

Using Catalyst 2900 Series XL Commands

This section describes how to perform the following tasks:

• Assign IP information to the switch

• Enable broadcast storm control for the switch

Assigning IP Information to the Switch

When you first power up the switch, you are prompted for IP information. To redisplay this series of prompts, enter the setup command in normal EXEC mode:

switch> setup

You can also enter IP information by following these steps:

Enabling Broadcast-Storm Control on a Port

Broadcast-storm control blocks the forwarding of packets created by broadcast storms, the bursts of broadcast traffic that ports can sometimes generate. When you enable broadcast-storm control on a port, two parameters define the beginning and end of a broadcast storm. The threshold rising parameter determines when the forwarding of broadcast packets from the port is blocked. The threshold falling parameter determines when normal forwarding resumes. You can set the port to generate a trap when these thresholds are crossed, and you can disable the port during a broadcast storm.

Switch ports are referred to with the constant fastethernet and a module and port number. Fixed ports are module 0, and 1 and 2 refer to the Catalyst 2916M expansion slot ports. The following examples are valid ports:

fastethernet0/8
fa2/2
fa2/1

Follow these steps to enable broadcast storm control:

Working with Files in Flash Memory

You can use the file system in Flash memory to copy files and troubleshoot configuration problems. Use the dir flash: command to display the contents of Flash memory:

Switch# dir flash:
Directory of flash:
  2  -rwx      843947   Mar 01 1993 00:02:18  C2900XL-h-mz-112.8-SA
  4  drwx        3776   Mar 01 1993 01:23:24  html
 66  -rwx         130   Jan 01 1970 00:01:19  env_vars
 68  -rwx        1296   Mar 01 1993 06:55:51  config.text
1728000 bytes total (456704 bytes free)

The file system uses a URL-based file specification. The following example uses the TFTP protocol to copy the file conffile.txt from the host arno to Catalyst 2900 Flash memory with the name bootfile:

switch# copy tftp://arno/2900/conffile.txt flash:bootfile

You can enter the following protocols as part of a file name:

• TFTP

• Flash

• RCP

• XMODEM

Enter the write memory command to save your configuration changes to NVRAM so that they are not lost if there is a system reload or power outage. This example shows how to use this command to save your changes:

switch# write mem
Building configuration...

It might take a minute or two to save the configuration to NVRAM of Flash. After the configuration has been saved, the following appears:

[OK]
switch#

Understanding the CLI

This section describes the Cisco IOS command-mode structure. Each command mode supports specific Cisco IOS commands. For example, the interface type_number command is used only when in global configuration mode.

The Catalyst 2900 series switches support the following command modes:

• User EXEC

• Privileged EXEC

• Global configuration

• Interface configuration

• Line configuration

Table 5-1 describes how to access each mode, the prompt you see in that mode, and how to exit the mode. The examples in the table use the host name switch.

Getting Help

You can use the question mark (?) and arrow keys to help you enter commands.

For a list of available commands in a command mode, enter a question mark:

switch> ?

To complete a command, enter a few known characters followed by a tab (with no space):

switch> s

For a list of command variables, enter the command followed by a space and a question mark:

switch> show ?

To redisplay a command you previously entered, press the up-arrow key. You can continue to press the up arrow key for more commands.

Setting Passwords

Because many privileged EXEC commands are used to set operating parameters, you should password-protect these commands to prevent unauthorized use.

You use two commands to do this:

• enable secret password password (a very secure, encrypted password)

• enable password password (a less secure, unencrypted password)

You must enter an enable password to gain access to privileged EXEC mode.

For maximum security, the passwords should be different. If you enter the same password for both during the setup process, your switch prompts you to make them different.

An enable secret password can contain from 1 to 25 uppercase and lowercase alphanumeric characters. An enable password can contain any number of uppercase and lowercase alphanumeric characters. In both cases, a number cannot be the first character. Spaces are also valid password characters; for example, "two words" is a valid password. Leading spaces are ignored; trailing spaces are recognized.

If you lose or forget your enable password, refer to the "Troubleshooting" chapter for a recovery procedure.

Abbreviating Commands

You only have to enter enough characters for the switch to recognize the command as unique. This example show how to enter the show configuration command:

switch# show conf

No Commands

The word no is a parameter that can be used as follows with most commands:

• Resets a command to its default values

• Reverses the action of a command. For example, the command no shutdown reverses the shutdown of an interface.

Command Line Error Messages

Table 5-2 lists some error messages that you might encounter while using the CLI to configure your switch.