Internet keeps getting disconnected

Hello all,

There is a strange thing happening. My internet keeps disconnecting. Its happens a lot. Apart from WiFi even the desktop computer that's directly connected to the router through a cable gets disconnected. It then reconnects again by itself after sometime.

And all the lights on the modem remain as it is i.e steady.

What might be the problem.

Broadband provided by Reliance

Thanks
Praveer