In 1988, DARPA decided that the experiment was over and started dismantling the ARPAnet. The National Science Foundation funded a network called the NSFNET and used it as the new backbone of the Internet.
In 1995, the NSFNET was replaced by multiple commercial backbones that were run by long-distance carriers like MCI and Sprint, and commercial internetworking companies like PSINet and UUNET.
Now, the Internet connects millions of hosts from all around the world. Tens of millions of people use the Internet for communication and collaboration every day through many methods such as email and instant messaging.
ARPA
In 1957, the US Department of Defense formed the Advanced Research Projects Agency (ARPA). Later on it would be known as DARPA. In the late 1960s, ARPA began funding an experimental wide area computer network called the ARPAnet. The ARPAnet connected research organizations across the US. Its original goal was to allow government contractors to share expensive and scarce computing resources. But ARPAnet users also used it for sharing files, exchanging e-mail, and other functions. In the early 1960's the TCP/IP protocol was developed and became the standard host-networking protocol of the ARPAnet. The network grew larger and larger, and the ARPAnet became the backbone of a group of networks, local and regional, based on TCP/IP. This large network was called the Internet.
Structure
The backbone of the Internet is a system of large interconnected networks known as Network Service Providers such as UUnet and PSInet. These networks are connected to Network Access Points (NAPs) and Metropolitan Area Exchanges (MAEs). Information can be passed through Network Access Points and Metropolitan Area Exchanges. The NAPs and MAEs are referred to as Internet Exchange points because it is where the information on the internet is exchanged.
Taken from www.duke.edu/
