Cisco IOS Software and the EXEC Facility Fundamentals

Cisco IOS Software Basic Skills

Getting Help

Accessing Different Command Modes

Undoing a Command or Feature

Saving Configuration Changes

Working with the EXEC Facility

Choosing a Method of Connecting to the Network

Connecting to the EXEC Facility

Where to Go Next

Cisco IOS Software and the EXEC Facility Fundamentals

If you are new to Cisco IOS software or need help understanding the EXEC facility and how it affects your network setup, you should read this chapter before starting configuration. Otherwise, proceed to Chapter 2, "Starting the AccessPath-VS3 System for the First Time."

Cisco IOS Software Basic Skills

This section describes what you need to know about the Cisco IOS software (the software that runs the Cisco AccessPath-VS3 Packet Telephony Concentrator) before you configure the AccessPath-VS3 system using the command-line interface (CLI). This section includes:

Understanding these concepts will expedite the configuration process. If you have never used the Cisco IOS software or need a refresher, take a few minutes to read this section before you proceed to the next section.

If you are already familiar with the Cisco IOS software, proceed to the section "Working with the EXEC Facility."

Getting Help

Use the question mark (?), Tab, and arrow keys to help you enter commands:

For a list of available commands, enter a question mark:

AS01> ?

To complete a command, enter a few known characters followed by a Tab:

AS01> ena<Tab>
enable

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

AS01> 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.
To display all the commands that start with a specific character or characters, enter the character(s) followed by a question mark (with no space):

AS01> e?

enable    end    endnode    exit

Note See the chapter "Configuring the User Interface" in the Configuration Fundamentals Configuration Guide for more information about any aspect of working with the user interface in the Cisco IOS software. The Configuration Fundamentals Configuration Guide is part of the Cisco IOS documentation for Cisco IOS Release 11.1 and later.

Accessing Different Command Modes

In addition to the EXEC facility, you can access several different command modes on AccessPath-VS3 system shelves. Each command mode permits you to configure different components. Table 1-1 lists the most common components and configuration modes.

You configure global parameters in global configuration mode, interface parameters in interface configuration mode, and line parameters in line configuration mode. For more information about using these configuration modes, see the Configuration Fundamentals Configuration Guide, which is part of the Cisco IOS documentation in Cisco IOS Release 11.1 and later.

Table 1-1: Common Command Modes
Command Mode Access Method Prompt Exit Method

User EXEC

Log in.

AS01>

Use the logout or exit command.

Privileged EXEC

From user EXEC mode, enter the enable EXEC command.

AS01#

To exit back to user EXEC mode, use the disable command.

Global configuration

From privileged EXEC mode, enter the configure terminal command.

AS01(config)#

To exit to privileged EXEC mode, use the exit or end command or press Ctrl-Z.

Interface configuration

Enter the interface type number command, such as interface ethernet 0.

AS01(config-if)#

To exit to global configuration mode, use the exit command.

To exit directly to privileged EXEC mode, use the end command or press Ctrl-Z.

Line configuration

Enter the line start-number end-number command, such as line 1 16.

AS01(config-line)#

To exit to global configuration mode, use the exit command.

To exit directly to privileged EXEC mode, use the end command or press Ctrl-Z.

System configurationdialog

From privileged EXEC mode, enter the setup command.

Continue with config dialog?

To exit to privileged EXEC mode, press Ctrl-C.

Table 1-1: **Common Command Modes**
Command Mode	Access Method	Prompt	Exit Method
User EXEC	Log in.	`AS01>`	Use the logout or exit command.
Privileged EXEC	From user EXEC mode, enter the enable EXEC command.	`AS01#`	To exit back to user EXEC mode, use the disable command.
Global configuration	From privileged EXEC mode, enter the configure terminal command.	`AS01(config)#`	To exit to privileged EXEC mode, use the exit or end command or press Ctrl-Z.
Interface configuration	Enter the interface type number command, such as interface ethernet 0.	`AS01(config-if)#`	To exit to global configuration mode, use the exit command. To exit directly to privileged EXEC mode, use the end command or press Ctrl-Z.
Line configuration	Enter the line start-number end-number command, such as line 1 16.	`AS01(config-line)#`	To exit to global configuration mode, use the exit command. To exit directly to privileged EXEC mode, use the end command or press Ctrl-Z.
System configurationdialog	From privileged EXEC mode, enter the setup command.	`Continue with config dialog?`	To exit to privileged EXEC mode, press Ctrl-C.

Note You can press Ctrl-Z in any mode to immediately return to enable mode (AS01#), instead of entering exit, which returns you to the previous mode.

Undoing a Command or Feature

If you want to undo a command you entered or disable a feature, enter the keyword no before most commands; for example, no ip routing.

Saving Configuration Changes

You need to enter the copy running-config startup-config command to save your configuration changes to nonvolatile random-access memory (NVRAM) so that they will not be lost if there is a system reload or power outage. For example:

AS01# copy running-config startup-config

Building configuration...

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

[OK]
AS01#

Proceed to the next section, "Working with the EXEC Facility," for additional information you will need before configuring the AccessPath-VS3 system.

Working with the EXEC Facility

This section introduces the EXEC facility, which you will use to configure your AccessPath-VS3 system.

Choosing a Method of Connecting to the Network

The prompt that appears when you first log in to any AccessPath-TS3 System Shelf is called the EXEC prompt. When you access the EXEC prompt, you are accessing the EXEC facility and starting an EXEC session. You can log in through the following ports on an VoIP Access Shelf:

Console port
LAN or WAN interface
Asynchronous interface

This section discusses how to configure the VoIP access shelves to permit remote clients to dial in and gain access to network resources (such as printers and file servers).

There are two ways you can enable remote clients to dial in and access network resources:

Have them access the EXEC facility and then access network resources via the EXEC session.
Have them connect directly to the network and bypass the EXEC facility.

In general, you should give system administrators access to the EXEC facility, but give dial-in clients access only to the network.

Connecting to the EXEC Facility

There are two primary levels to the EXEC facility:

User-level EXEC mode --- What you see when you first log in to a VoIP Access Shelf, from a remote client, or through a console port connection:

AS01>

Privileged-level EXEC mode --- Provides access to configuration mode. To enter the privileged-level EXEC mode, issue the enable command, enter the enable password, and press Return, as shown in the following example:

AS01> enable

Password: <password>
AS01#

AccessPath-VS3 system network administrators should protect the privileged-level EXEC mode with a password that only network administrators know. This gives users access only to the user-level EXEC mode so that they can issue commands to connect with other network devices (such as the ppp command) and prevents them from changing the configuration of the AccessPath-VS3 system.

For an overview of configuration mode, see the section, "Accessing Different Command Modes." For information about configuring security, see Chapter 5, "Configuring Security for the AccessPath-VS3 System."

Where to Go Next

Now that you have learned some Cisco IOS software and EXEC facility basics, you are ready to configure the AccessPath-VS3 system using the CLI.

Remember that:

You can use the question mark (?), Tab, and arrow keys to help you enter commands.
Each command mode restricts you to a specific set of commands. If you are having difficulty entering a command, check the prompt and then enter the question mark (?) for a list of available commands. You might be in the wrong command mode or using the wrong syntax.
If you want to undo a command or disable a feature, enter the keyword no before the command; for example, no ip routing.
You need to save your configuration changes to NVRAM so that they will not be lost if there is a system reload or power outage. There are three commands that will do this:
- write
- write memory
- write running-config startup-config

Table of Contents

Cisco IOS Software and the EXEC Facility Fundamentals