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Cisco IOS Command-Line Interface

This section describes how to use the Cisco IOS command-line interface (CLI). This section is not intended to be a complete tutorial on IOS commands. Instead, it provides novice users with the fundamental skills to use the CLI.

It is assumed that you do not have experience on Cisco IOS products. However, it is highly recommended that you attend appropriate Cisco training courses before attempting to configure an RPM in a live network environment.

RPM CLI Access

The RPM CLI can be accessed using any of the following three methods:

  • Console port on the front of the RPM—The RPM has an RJ-45 connector on the front of the card module. A PC or dumb terminal can be directly attached to this port with an EIA/TIA-232 to RJ-45 cable for CLI access. The console port is the only way to access the RPM CLI when the card module is first installed into an MGX chassis.

  • cc from another MGX card—You can access the RPM CLI using the cc (change card) command from any of the other cards in the MGX switch. The ATM switch interface on the RPM must be enabled before you can use the cc command.

  • Telnet from a workstation, PC, or another router—The RPM CLI can be accessed from a PC or workstation on any of the LANs attached to the RPM. Also, after the RPM is installed and has PVCs to other RPMs or routers in the network, you can Telnet to the RPM CLI remotely from these other devices.

CLI Modes

The RPM, like all Cisco routers, has seven modes of operation:

  • User EXEC mode— Once you have logged into the router CLI, be aware that you will have limited read access to the status and configuration of the router in this mode.

  • Privileged EXEC mode—In privileged EXEC mode, you can access detailed status and configuration information and modify the router's configuration files. To enter privileged EXEC mode, use the enable command. An additional password might be required to access privileged EXEC mode.

  • ROM monitor mode—ROM monitor mode is used when a router is first initialized and does not have a configuration file. Interrupting the boot process with a keyboard break sequence also starts ROM monitor mode.

  • Setup mode—Setup mode is a prompted configuration sequence that is used when a router is first initialized.

  • RX boot mode—The boot helper software that is used if the router cannot access the Cisco IOS image.

  • Global configuration mode—A mode in which configuration changes can be made that affect the general router operation. For example, changing the router host name is a global configuration command.

  • Other configuration modes—Other configuration modes for modifying specific router elements are accessed from configuration mode. For example, to make configuration changes on an Ethernet interface, enter interface ethernet 9/1/1 while in configuration mode.

Entering Commands

When you are logged into the RPM, you enter commands at the command prompt. Most commands can be abbreviated using a few letters, provided that the abbreviation is unique. For example, you can enter sho int instead of show interface. Entering sho i is not enough, because several keywords start with the letter i, such as ip and ipx. In this book, all commands and keywords are spelled out in their entirety.

The Tab key completes an abbreviated word or provides you with choices based on the letters you have entered. For example, if you enter sho and then press Tab, the system spells out show on the command line.

The ? key provides the next keyword or parameter if you are unsure of your options. For example, if you enter show ?, the system displays a list of possible choices, such as interface, configuration, and memory.

Preceding a command with no negates most configuration commands. For example, to assign an IP address to an interface, use the ip address command. To remove an IP address from an interface, use the no ip address command.

Changing the RPM Configuration

Before making changes to a configuration file, you should view the file using one of the following commands:

  • show running-config
  • show startup-config

When you enter configure terminal, you execute the configuration commands from the terminal. In this case, you make changes to the running configuration.

If you want to make changes to a configuration file other than the current running configuration, you need to copy the file into the running configuration by entering one of the following commands:

  • copy startup-config running-config—Copies the startup configuration into the running configuration. When this command is complete, you can use the configure terminal command to enter configuration mode.

  • copy c:filename running-config—Copies the configuration file named filename that is stored on the PXM hard drive into the running configuration. When this command is complete, you can use the configure terminal command to enter configuration mode.


    The configuration file named filename is stored in the RPM directory of the PXM hard drive.

  • copy tftp running-config—Copies a configuration file from a Trivial File Transfer Protocol (TFTP) server into the running configuration. You are prompted for the server name or address and the filename. When this command is complete, you can use the configure terminal command to enter configuration mode.

If you want to go from a specific configuration mode (for example, interface configuration mode) to global configuration mode, use the exit command. From any configuration mode, press Ctrl-Z to exit. The changes you made are automatically stored in the running configuration file in RAM.

After you determine that the new configuration is correct, you must save your changes to the startup configuration file. Saving the changes ensures that the router uses the changes when you copy the startup configuration file into memory or perform a reload. Save the configuration using one of the following methods:

  • copy running-config startup-config—Saves the configuration variables to the startup configuration file in NVRAM.

  • copy running-config c:filename—Saves the configuration variables to a file named filename on the PXM hard drive.

  • copy running-config tftp—Saves the configuration variables to a remote server on the network. The variable tftp represents the target server type.

Example 22-15 shows an example of making a configuration change to the RPM.

Example 22-15 Making a Configuration Change to the RPM


RPM-PR_NY_9#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.

RPM-PR_NY_9(config)#interface switch 9/1

RPM-PR_NY_9(config-if)#ip address ?
 A.B.C.D IP subnet mask

RPM-PR_NY_9(config-if)#ip address ?
 secondary Make this IP address a secondary address

RPM-PR_NY_9(config-if)#ip address


RPM-PR_NY_9#copy running-config startup-config
Destination filename [startup-config]?
Building configuration...


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