reset the router

Why restart the router can fix many problems?
when there is no internet, you know what to do: unplug the router or modem and then wait ten seconds and plug it back in. once rebooted, you can connect to the internet again. but why restarting this router is really effective? and what happened miraculously in these ten seconds?
How to find the default IP address of a Belkin router
the router manufacturer sets the default private ip address used for the local network and the home network administrator controls it. the default ip address of all belkin routers is 192.168.2.1.