What is the Internet? The Internet is a loose association of thousands of networks and millions of computers across the world that all work together to share information. Like many complex systems, the Internet is easiest to explain through the use of metaphors, and the Net has inspired its fair share. The one that has stuck is the "information superhighway," and while it has become a cliché, the transportation analogy really does hold up pretty well. Think of the Internet as a mondo version of a mass transit system like Boston's T, with a few main subway lines that intersect at certain points. Connecting to the subway lines are commuter rails, bus lines, and ferry boats that spread out and crisscross the metropolitan area. On the Net, the main lines carry the bulk of the traffic and are collectively known as the Internet backbone. The backbone is formed by the biggest networks in the system, owned by major Internet service providers (ISPs) such as GTE, MCI, Sprint, UUNet, and America Online's ANS. By connecting to each other, these networks create a superfast pipeline that crisscrosses the United States and extends to Europe, Japan, mainland Asia, and the rest of the world. But that doesn't mean that the network is equally well developed at every point along the route. The U.S. backbone has so many intersecting points that if one part fails or slows down, data can be quickly rerouted over another part, a feature called redundancy. Overseas, the network may have less redundancy and so be more vulnerable to slowdowns or breakdowns. In the United States, there are five points--located in San Francisco, San Jose (California), Chicago, New York (actually, Pennsauken, New Jersey), and Washington, D.C.--where the main lines intersect, kind of like how the major U.S. airlines have hub cities. Confusingly enough, three of these are called network access points (NAPs), while the other two are called metropolitan area exchanges (MAEs), but they basically do the same thing: use high-speed networking equipment to connect the backbone to other networks (see Figure 1). These networks are owned by smaller regional and local ISPs, which in turn lease access to companies and individuals in the areas they serve.   Government agencies and universities are also actively involved in running the parts of the Internet that link supercomputer centers devoted to the research and education communities. While this used to be the main purpose of the Net, the explosion of private and corporate use has caused a huge traffic jam on the backbone. Academics now complain that they can't get their work done because the network is too packed with everybody else. With help from these communities, as well as financial support from the private sector, Congress has been actively planning the Next Generation Internet. It aims to deliver on President Clinton's pledge to build and promote a new and faster network that will form a second backbone over the next five years. This Internet II, as it's sometimes called, will not replace the existing Net, but will provide alternate routes for academics and government agencies to share information without getting caught in commercial traffic.

 

 

Who controls the Net? No one person, company, institution, or government organization owns the Internet. No one source foots the bill for it. No one entity governs it, or even has a controlling interest. The Internet is truly a collaborative, collective enterprise. Many institutions and companies donate their computer resources in the form of servers and computer technicians to hold up some part of the Internet--for example, critical links between different regions. Governments around the world are also starting to exert their influence through legislation. And every computer on the Net has to understand a basic set of technologies, which several organizations are involved in maintaining, updating, and disseminating. There are a handful of organizations that are truly influential and that taken together form a sort of checks-and-balances system:   The World Wide Web Consortium (W3C) sets the standards for HTML and other specifics of the Web. The Internet Engineering Task Force (IETF) focuses on the evolution of the Internet with a specific eye toward keeping the Internet running smoothly as a whole. The Internet Engineering Steering Group (IESG) is a related organization responsible for managing IETF activities and the Internet standards process. The Internet Architecture Board (IAB) is responsible for defining the overall architecture of the Internet (the backbone and all the networks attached to it), providing guidance and broad direction to the IETF.   The Internet Society (ISOC) is a supervisory organization made up of individuals, corporations, nonprofit organizations, and government agencies from the Internet community. The group comments on Internet policies and practices and oversees a number of other boards and task forces--including the IAB and IESG--dealing with Internet policy issues. The Internet Assigned Numbers Authority (IANA) and the Internet Network Information Center (InterNIC) lead the organizations responsible for assigning IP addresses and domain names, respectively.   Regional and long-distance phone companies, backbone ISPs, cable and satellite companies, and the U.S. government all contribute in significant ways to the telecommunications infrastructure that supports the Internet. Some of these companies, such as UUNet, BBN, Sprint, and MCI, have found ways to make lots of money by leasing access to the Internet to other companies. As the commercial potential of the Net matures even more, these companies might begin to throw their weight around. Several major ISPs have already banded together to hash out industry-wide technical issues. But no one can wrest away total control of the Net, which is why it's not just a communications medium, but a metaphor for the new global economy.

How does the Net work? The secret of the Net is a network protocol called TCP/IP--that is, a kind of coding system that lets computers electronically describe data, like the contents of this story, to each other over the network. The term actually refers to two separate parts: the transmission control protocol (TCP) and the Internet protocol (IP). Together they form the Esperanto of the Internet. Every computer that hooks to the Internet understands these two protocols and uses them to send and receive data from the next computer along the network. TCP/IP creates what is called a packet-switched network, a kind of network intended to minimize the chance of losing any data that is sent over the wires. First, TCP breaks down every piece of data--such as an email message or instructions from a Java applet--into small chunks called packets, each of which is wrapped in an electronic envelope with Web addresses for both the sender and the recipient. The IP protocol then figures out how the data is supposed to get from point A to point B by passing through a series of routers--sort of like regular mail passes through several post offices on its way to a remote location. Each router examines the destination addresses of the packets it receives and then passes the packets on to another router as they make their way to their final destination. If your email was broken into ten packets, then each of those may have traveled a completely separate route. But you'll never know it, because as the packets arrive, TCP takes over again, identifying each packet and checking to see if it's intact. Once it has received all the packets, TCP reassembles them into the original. (See Figure 2.)   TCP/IP is the most important of a long list of Internet protocols. It is sometimes used as a global term to describe additional protocols, including simple mail transfer protocol (SMTP), file transfer protocol (FTP), and Telnet protocol.

	http://www.belnet.be/main_nl.html  en zet  u in tools en kies dan de menu-item tracerouter.Geef dan een IP adres op bv www.pandora.be . De verschillende plaatsen waardoor de oproep is gepasseerd  verschijnen nu en de tijd die verstreken is .Hier kunt u zien waar de bottlenecks zich bevinden.
	In windows ( infeite in msdos mode ) is er ook een tracer . Zet  u in msdos-mode via 'programs' in uw startmenu.Typ dan tracert www.pandora.be .Na enige tijd verschijnen de verschillende routers waarlangs de oproep is gepasseerd.