1. The Internet Trisha Cummings ITE115

2. What is the Internet? The Internet is a world-wide network of computer networks that use a common communications protocol, In the late sixties, the Advanced Research Projects Administration (ARPA), a division of the U.S. Defense Department, developed the ARPAnet to link together universities and high-tech defense contractors.

3. Packet Switching Packet switching is a technique that divides a message into smaller units, sends those packets to their destination by the best route available, and reassembles the packets at the receiving end. This technology made the Internet possible.

4. The Internet technology is connectionless. This means that there is no end-to-end setup for a session; each packet is independently routed to its destination. When a packet is ready, the host computer sends it on to another computer, known as a router. The router examines the destination address in the header and passes the packet along to another router, chosen by a route-finding algorithm. A packet may go through 30 or more routers in its travels from one host computer to another. Because routes are dynamically updated, it is possible for different packets from a single session to take different routes to the destination. Along the way packets may be broken up into smaller packets, or reassembled into bigger ones. When the packets reach their final destination, they are reassembled at the host computer.

5. TCP/IP Transmission Control Protocol/Internet Protocol the set of communications protocols used to connect hosts on the Internet. TCP/IP uses several protocols, the two main ones being TCP and IP.

6. Introduction to TCP/IP TCP and IP were developed by a Department of Defense (DOD) research project to connect a number different networks designed by different vendors into a network of networks (the "Internet"). It was initially successful because it delivered a few basic services that everyone needs (file transfer, electronic mail, remote logon) across a very large number of client and server systems. Several computers in a small department can use TCP/IP (along with other protocols) on a single LAN. The IP component provides routing from the department to the enterprise network, then to regional networks, and finally to the global Internet.

7. On the battlefield a communications network will sustain damage, so the DOD designed TCP/IP to be robust and automatically recover from any node or phone line failure. This design allows the construction of very large networks with less central management. However, because of the automatic recovery, network problems can go undiagnosed and uncorrected for long periods of time.