The Internet, that has been around since the early seventies when TCP/IP emerged and grew strong up to the nineties is actually just a global connection of a lot of local area networks. At the beginning only traffic between different University sites traversed the net. After a while also the business community started to show interest in the net and a global structure emerged. The growth was very strong as the academic world supported common use of the net.

The connection of local networks is accomplished with so called routers. A router has two or more connected, today mostly ethernet but also ADSL and other common protocols used by telecom operators. The routers communicate with each other with a so called routing protocol. Some common used routing protocol is RIP, OSPF or BGP. The task of the routing protocol is to announce what network is connected or known by other routers. This way all routers can know all networks connected and reachable and distribute the traffic to the shortest path or path preferred by other means. The Swedish part of the Internet is today managed by Netnode.

To globally identify single computers on the net today is an addressing method with more than 4 billion addresses used. More about this is described under the IP chapter.

In your applications on the computer IP-addresses is not used to identify the receiver but words that we human beings have easier to remember. A global system to translate words to numbers is also developed for the Internet, it is called the DNS (Domain name system), more about this system in the DNS chapter.

A system with so called GIX (Global Internet exchange) is built all over the world. A GIX is only a IP switch which distribute traffic between different connected network providers. There is no rules how to distribute traffic between different providers but it is a matter between themselves.

So when you send an e-mail to your aunt in Los Angeles first the IP-address to her mail server is looked up with DNS, then the mail is forwarded through several telecom operators between the GIX:e's to the destination at your aunts mail operator.