Ever busy with a scheduled change, and the configuration all of a sudden differs from what you configured five minutes ago?
Normal IOS (not XR) behaviour allows multiple users to make instant changes to the running configuration. Occasionally two users make changes to the same config portion at the same time. One overwriting the others. ONLY the last commands entered will take effect.
The Configuration Lock feature allows a one to have exclusive change access to the Cisco IOS running configuration, preventing multiple users from making concurrent configuration changes.
There are two modes: