Table Of Contents

Using the Command-Line Interface

Type of Memory

Platforms

CLI Command Modes

User EXEC Mode

Privileged EXEC Mode

VLAN Configuration Mode

Global Configuration Mode

Interface Configuration Mode

Line Configuration Mode

Using the Command-Line Interface

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The Catalyst 3550 multilayer switches are supported by Cisco IOS software. These switches support Cisco IOS Release 12.1(4)EA1. This chapter describes how to use the switch command-line interface (CLI) to configure software features.

For a complete description of the commands that support these features, see "Cisco IOS Commands." For information on the boot loader commands, see "Boot Loader Commands." For more information on Cisco IOS Release 12.1, refer to the Cisco IOS Release 12.1 Command Summary.

For task-oriented configuration steps, refer to the Catalyst 3550 Multilayer Switch Software Configuration Guide for this release.

Type of Memory

The switch Flash memory stores the Cisco IOS software image, the startup configuration file, and helper files.

Platforms

This IOS release runs on a variety of switches and modules. For a complete list, refer to the Release Notes for the Catalyst 3550 Multilayer Switch.

CLI Command Modes

This section describes the CLI command mode structure. Command modes support specific Cisco IOS commands. For example, the interface interface-id command only works when entered in global configuration mode. These are the main Cisco IOS command modes:

•User EXEC mode

•Privileged EXEC mode

•VLAN configuration mode

•Global configuration mode

•Interface configuration mode

•Line configuration mode

Table 1-1 lists the main command modes, how to access each mode, the prompt you will see in that mode, and how to exit that mode. The prompts listed use the default name Switch.

Table 1-1 Command Modes Summary 

Command Mode	Access Method	Prompt	Exit or Access Next Mode
User EXEC	This is the first level of access. (For the switch) Change terminal settings, perform basic tasks, and list system information.	Switch>	Enter the logout command. To enter privileged EXEC mode, enter the enable command.
Privileged EXEC	From user EXEC mode, enter the enable command.	Switch#	To exit to user EXEC mode, enter the disable command. To enter global configuration mode, enter the configure command.
VLAN configuration	From privileged EXEC mode, enter the vlan database command.	Switch(vlan)#	To exit to privileged EXEC mode, enter the exit command.
Global configuration	From privileged EXEC mode, enter the configure command.	Switch(config)#	To exit to privileged EXEC mode, enter the exit or end command, or press Ctrl-Z. To enter interface configuration mode, enter the interface configuration command.
Interface configuration	From global configuration mode, specify an interface by entering the interface command.	Switch(config-if)#	To exit to privileged EXEC mode, enter the end command, or press Ctrl-Z. To exit to global configuration mode, enter the exit command.
Line configuration	From global configuration mode, specify a line by entering the line command.	Switch(config-line)#	To exit to global configuration mode, enter the exit command. To return to privileged EXEC mode, enter the end command, or press Ctrl-Z.

User EXEC Mode

After you access the device, you are automatically in user EXEC command mode. The EXEC commands available at the user level are a subset of those available at the privileged level. In general, the user EXEC commands allow you to temporarily change terminal settings, perform basic tests, and list system information.

The supported commands can vary depending on the version of IOS software in use. To view a comprehensive list of commands, enter a question mark (?) at the prompt.

Switch> ? 

Privileged EXEC Mode

Because many of the privileged commands configure operating parameters, privileged access should be password-protected to prevent unauthorized use. The privileged command set includes those commands contained in user EXEC mode, as well as the configure privileged EXEC command through which you access the remaining command modes.

If your system administrator has set a password, you are prompted to enter it before being granted access to privileged EXEC mode. The password is not displayed on the screen and is case sensitive.

The privileged EXEC mode prompt consists of the device name followed by the pound sign (#).

Switch#  

Enter the enable command to access privileged EXEC mode:

Switch> enable 

Switch# 

The supported commands can vary depending on the version of IOS software in use. To view a comprehensive list of commands, enter a question mark (?) at the prompt.

Switch# ? 

To return to user EXEC mode, enter the disable privileged EXEC command.

VLAN Configuration Mode

You can use the VLAN configuration commands to modify VLAN parameters. Enter the vlan database privileged EXEC command to access VLAN configuration mode:

Switch> vlan database

Switch(vlan)# 

The supported commands can vary depending on the version of IOS software in use. To view a comprehensive list of commands, enter a question mark (?) at the prompt.

Switch(vlan)# ? 

To return to privileged EXEC mode, enter the abort VLAN configuration command to abandon the proposed database. Otherwise, enter exit to implement the proposed new VLAN database and to return to privileged EXEC mode.

Global Configuration Mode

Global configuration commands apply to features that affect the device as a whole. Use the configure privileged EXEC command to enter global configuration mode. The default is to enter commands from the management console.

When you enter the configure command, the console prompts you for the source of the configuration commands:

Switch# configure 

Configuring from terminal, memory, or network [terminal]?

You can specify either the terminal or nonvolatile RAM (NVRAM) as the source of configuration commands.

The following example shows you how to access global configuration mode:

Switch# configure terminal 

Enter configuration commands, one per line.  End with CNTL/Z. 

The supported commands can vary depending on the version of IOS software in use. To view a comprehensive list of commands, enter a question mark (?) at the prompt.

Switch(config)# ? 

To exit global configuration command mode and return to privileged EXEC mode, enter the end or exit command, or press Ctrl-Z.

Interface Configuration Mode

Interface configuration commands modify the operation of the interface. Interface configuration commands always follow a global configuration command, which defines the interface type.

Use the interface interface-id command to access interface configuration mode. The new prompt means interface configuration mode.

Switch(config-if)#

The supported commands can vary depending on the version of IOS software in use. To view a comprehensive list of commands, enter a question mark (?) at the prompt.

Switch(config-if)# ?

To exit interface configuration mode and return to global configuration mode, enter the exit command. To exit interface configuration mode and return to privileged EXEC mode, enter the end command, or press Ctrl-Z.

Line Configuration Mode

Line configuration commands modify the operation of a terminal line. Line configuration commands always follow a line command, which defines a line number. These commands are used to change terminal parameter settings line-by-line or for a range of lines.

Use the line vty line_number [ending_line_number] command to enter line configuration mode. The new prompt means line configuration mode. The following example shows how to enter line configuration mode for virtual terminal line 7:

Switch(config)# line vty 0 7 

The supported commands can vary depending on the version of IOS software in use. To view a comprehensive list of commands, enter a question mark (?) at the prompt.

Switch(config-line)# ? 

To exit line configuration mode and return to global configuration mode, use the exit command. To exit line configuration mode and return to privileged EXEC mode, enter the end command, or press Ctrl-Z.