If a computer has an connection to the Internet, It is connected to a router that the computer sends data to. This is the first router the computer will connect to in order to get to the internet. It is known as a default gateway because it is the 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 a computer makes a connection (such as a connection to www.wikipedia.org), the IP address of the destination server is found using a service called DNS (Domain Name System). Once the destination address has been found, the computer connects to the gateway router. The gateway then sends data to a router at the ISP (Internet Service Provider). That router is a part of the internet and connects to other routers until the data reaches the destination.