The Internet's Physical Layer

There are thousands of Internet Service Providers who provide access to individual users and companies. A long  list of providers is located at The List.  Out of these many thousands of ISP's, there are only a handful which operate extensive high-speed backbone networks. Most other ISP's derive their connectivity from the larger ISP's. Russ Haynal's ISP Page lists the major ISP's

Many ISP's interconnect with each other at Exchange Points (EPs) It is at the EP's that the end-user traffic from ISP#1 can transfer over to ISP#2 to reach a host computer/network which happens to be connected to ISP#2. EP.net  has a long  list of Exchange Points from around the world.   Examining the list of ISP's connected at each EP, will help indicate which ISP's are the major providers.

Most recently, the top ISP's (UUNET, SPRINT, Cable & Wireless, etc.) have begun to increase the amount of "private peering" they do between themselves and a few of the other ISP's. These providers have several connections dedicated to inter-connecting their backbones without going through the EP's.

If you are interested in even more details about how the Internet operates, explore:

• The Internet Society (ISOC) and it's technical groups such as The Internet Engineering Task Force (IETF)
• Requests for Comments (RFC's) - RFC's define the protocols that "run" the Internet. To truly understand how information moves across the Internet, you must learn about TCP-IP, Domain names, and the many protocols associated with each internet application.

Routing Details:

Finally, some interesting trivia for those of you who are wondering just how large the Internet can become. The next generation of IP address space (IPng) will be 128 bits long. This results in an address space size of: 340,282,366,920,938,463,463,374,607,431,768,211,456 . Depending on the overhead for this addressing architecture, IPng will provide anywhere from 1,564 to 3,911,873,538,269,506,102 addresses for every square meter of the Earth's surface area. What will we do with all these addresses? Explore this list of interesting devices connected to the Internet. Explore around to see Interactive Video Cameras, Live traffic Video in Montgomery County.

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