++
++
The Internet is a global collection of interconnected computer networks, both big and small. Since its initial development in 1969, when it consisted of four host computer systems, to the present, the Internet has grown dramatically by almost any measure, although there are wildly conflicting claims as to the rate of growth. Some have stated that the Internet’s size doubles every 3 months, while others suggest that it doubles only every year. The Internet was funded by the National Science Foundation (NSF) until the end of 1994 and since then its explosive growth has been a function of its inherent success.
++
The Internet is directly and appropriately analogous to our system of roads (or for that matter, phones, electricity, piped gas, piped water, or sewers), with small roads leading onto ever larger highways. A personal computer, for example, may link to the Internet through a cable modem, which links to a regional carrier’s (such as ATT or Comcast) “point of presence” (POP). The carrier, in all likelihood, has POPs dispersed across the geographic area it serves, and each POP connects to a “network access point,” or NAP. With each connection, the available bandwidth increases, much as dirt roads connect to multilane highways; and the final common pathway is the Internet backbone. The terminal or endpoint computers can make their initial connection to the Internet in a variety of ways, include a wireless connection at, for example, a wireless access point in a Starbucks, through a modem from a hotel room or from a networked computer on a LAN. Communications from all of these computers will ultimately traverse the Internet over the backbone (assuming the communications are intended for a destination that is not part of the originating network) (Fig. 5-1).
++
++
Key Points
The organization of the core of the Internet parallels that of the telephone networks.
Network service providers (NSPs) service the backbone of the Internet (like telephone long distance carriers).
Internet service providers (ISP’s) service the consumer and buy access to the core from NSPs (like local phone companies).
NAPs are physical locations where backbone Internet cables and computers meet and interact.
POPs are physical locations where the equipment of ISPs, such as the mail and web servers, are located.
POPs need to connect to NAPs to provide their customers with access to the Internet.
++
The Internet can probably best be understood using a brief history of the telephone network as a background. The original telephone network was AT&T, and it existed as a monopoly, providing both local phone access and long distance connections, until its breakup in ...