All command-line interface (CLI) configuration changes to a Cisco router are made from the global configuration mode. Other more specific modes are entered depending upon the configuration change that is required, but these specific modes are all subsets of the global configuration mode.

Global configuration mode commands are used in a router to apply configuration statements that affect the system as a whole. The following command moves the router into global configuration mode and allows entry of commands from the terminal:

Note: The prompt changes to indicate that the router is now in global configuration mode.

Router#configure terminal
Router(config)#

Global configuration mode, often shortened to global config, is the primary configuration mode. These are just a few of the modes that can be entered from global configuration mode:

• Interface mode
• Line mode
• Router mode
• Subinterface mode
• Controller mode

When these specific modes are entered, the router prompt changes to indicate the current configuration mode. Any configuration changes that are made will apply only to the interfaces or processes covered by the particular mode.

Typing exit from one of these specific configuration modes will return the router to global configuration mode. Pressing Ctrl-Z leaves the configuration modes completely and returns the router to privileged EXEC mode.

Web Links Cisco IOS Interface Command Reference, Release 12.1 http://www.cisco.com/en/US/ products/sw/ iosswrel/ ps1831/ products_command_reference_ book09186a00800880d1.html