How to Powercycle Router

Power-cycle

•  First turn off all the computers or other devices which are connected to router like printer,   i-phone or any other (as they are the end elements or users of the system)
•  Now turn off the router by unpluging the power cable from it. (This is intermediate element between modem and router)
•  Finally turn off the modem might be a cable or dsl modem. If the modem have battery backup do take out the batteries. (This is the primary equipment)

Now just wait for 1 minute. Hold your breath because modem releases IP after 30 to 45 seconds........

•  Now turn on modem first and wait till you have all lights lit on it... like on dsl modem...power,dsl,internet,ethernet  &  on cable modem .... power,internet,downstream,upstream,ethernet.
•  Afterward turn on router & just wait till power light is steady.
•  Finally turn on all the computers and other devices. And you are good to go....... 

Now at last few reasons why you need to power cycle your system:-

1. You was online and somehow you lost the connection.
2. Speed is slow you can try this a first step. Can you believe this that it might resolve the issue.
3. After you are done setting up the router.