Routers are the traffic cops of the network. They tell network traffic how to move from one IP subnet to the next IP subnet. There work is platform independent, so it doesn’t any anything to do with what kind of computers are on each end of the connection.
Let’s use a basic example. Say you are in India and your computer has been assigned an IP address of 220.127.116.11 and you want to talk to the ITKE web site which is hosted on the IP 18.104.22.168. Because of the way that TCP/IP works (TCP/IP is the language which the Internet uses so that computers can talk to each other) your computer can not talk to the ITKE computer directly. Computers can only talk to other computers or devices on the same subnet as them. Typically a subnet will be a group of 256 IP address which share the same first three parts (in this case 42.52.41.x and 75.126.27.x). In order for you to talk to a computer or device on another subnet you need to use a router. Routers are special devices which basically have two network cables on them. With each network cable configured for a different network.
In order to go from your computer to the ITKE computer you will need to go through many routers to get to the web site as there are many networks which you must travel to get to the web server here. First your ISP will probably have a few routers that you have to go through, then the company which sells them bandwidth will have a couple, then the back bone provider (ATT, Global Crossing, Sprint, etc) then the ITKE’s ISP will have a couple of routers, then the TechTarget (who owns the ITKE) will have a couple of routers before you get to the actual web server.