How Web Servers Work

So what is "the Internet"? The Internet is a gigantic collection of millions of computers, all linked together on acomputer network. The network allows all of the computers to communicate with one another. A home computer may be linked to the Internet using aphone-line modem,DSLorcable modemthat talks to an Internet service provider (ISP). A computer in a business or university will usually have a network interface card (NIC) that directly connects it to alocal area network(LAN) inside the business. The business can then connect its LAN to an ISP using a high-speed phone line like aT1 line. AT1 linecan handle approximately 1.5 million bits per second, while a normal phone line using a modem can typically handle 30,000 to 50,000 bits per second.

ISPs then connect to larger ISPs, and the largest ISPs maintain光纤"backbones" for an entire nation or region. Backbones around the world are connected through fiber-optic lines, undersea cables orsatellitelinks (seeAn Atlas of Cyberspacesfor some interesting backbone maps). In this way, every computer on the Internet is connected to every other computer on the Internet.