If you have an Internet connection, you probably have a router somewhere that your computer sends data to. This is the first router your computer will connect to in order to get to the internet. It is also known as a default gateway (because it is your gateway to the internet). By convention the gateway has the lowest IP address (like a phone number for a computer) in the subnet (a group of addresses). Anytime you make a connection (such as a connection to www.wikipedia.org) your computer looks up the IP address using the look-up service called DNS (Domain Name Service). Once the destination address has been found your computer connects to your gateway router. The gateway then sends data to a router at your ISP (Internet Service Provider), that router can be said to be part of the internet and connects to other routers until the data reaches the destination.
In small networks such as homes, small businesses (including internet cafés) and small schools, the router also performs NAT (network address translation) which makes all outgoing connections look like they come from one address.

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