Voice interface must be shutdown before updating configuration
If the power is lost, the NVRAM will preserve this configuration.In other words, if you edit the router's configuration, don't use this command and reboot the router—those changes will be lost.The Thing Handler implementation must be prepared to handle different command types depending on the item types, that are defined by the channels.
Cisco routers have different modes where only certain things can be shown or certain things can be changed.
As the IOS is a command-line operating system with thousands of possible commands and parameters, using the command shows the router, switch, or firewall's current configuration.
The running-configuration is the config that is in the router's memory.
When you're having trouble with an interface, you may want to try a command is used to show the router's routing table.
This is the list of all networks that the router can reach, their metric (the router's preference for them), and how to get there.
You change this config when you make changes to the router.