The Internet
The Internet is by far the largest network in existence, with hundreds of millions of systems connected in an enormous multi-protocol, varied media, globe-spanning network. But the Internet didn't spring into being overnight. The parent network of the modern Internet was called ARPAnet and was created by the United States Defense Advanced Research Projects Agency in 1969. Originally created as a test bed for new networking technologies, the ARPAnet linked many different universities and research centers (the first two nodes making up the ARPAnet were UCLA and the Stanford Research Institute). As more and more nodes were added, the inherent value of connecting systems to facilitate the sharing of information became obvious. Eventually, additional research facilities and universities were added and over time the commercial sector began to connect systems as well. Though the exact birth date of the Internet is debatable, some scholars consider the decommissioning of the ARPAnet in 1990 as the official start of the modern Internet.
The Internet today is an amazing jumble of useful and useless information with an astounding number of opportunities and an overwhelming number of dead ends. You can buy, sell, or trade almost anything over the Internet. You can find the most obscure fact, listen to your favorite music, watch video clips, check the weather, read the news, and send and receive messages all over the Internet. In many ways, the Internet has revolutionized the way society operates and interacts. Yet, as mammoth and prolific as the Internet seems there is still a significant portion of the world's population that does not have access to and may never surf the Internet.
One of the biggest challenges facing the Internet today is the struggle to provide high-speed, reliable access direct to the individual home user. Although broadband technologies such as cable modems, Digital Subscriber Lines (DSL), satellite, and high-speed wireless provide better access and content delivery to homes in areas where such technologies are available, most Internet users connect via a plain old telephone line and an analog modem.
The average dial-up user is in good company. There are millions of other users using the same access method:
The user attempts to establish a dial-up connection with an Internet service provider. (Some users prefer small, local ISPs whereas others use nationwide ISPs such as America Online or EarthLink.)
When the modem connected to the user's computer connects with the modem at the service provider, they go through a negotiation process to establish the lower-level communications capability.
After negotiation, the user authenticates with a userid/password combination to identify her to the ISP as a legitimate user.
If successfully authenticated, the ISP then uses DHCP to configure the user's network settings. (The IP address, default gateway, and name server are all the necessary components to communicate with other networks.)
The user can then launch her favorite browser, mail reader, or network application and be on her way.
Within the ISP, Internet-bound traffic received from individual users is collected and funneled onto dedicated, always on, full-time connections that attach the ISP to a larger upstream provider. Depending on the size of the ISP and its immediate provider, this process may be repeated several times.
Eventually, the traffic will pass up enough levels in the hierarchical network structure of the Internet and it will reach the backbone or core of the Internet. The Internet backbone is an extremely high-speed network made up of numerous, redundant connections managed by companies such as MCI, Sprint, and Cable and Wireless. Through the use of routing protocols and name resolution services, the individual user traffic will eventually exit the backbone at the appropriate spot onto a smaller provider network. Once off the backbone, traffic will be passed from provider to smaller provider until it reaches the intended destination. Any response from the destination back to the originator will perform the same process in reverse.
Looking at the overall structure and function of the Internet, it's not hard to see why we experience delays in Internet traffic, especially when considering the amazing rate of Internet growth. That being said, the majority of user-experienced delay is due to destination problems such as overloaded servers and graphics-intensive Web sites, or the end user's connection itself. As consumers continue to demand more high-quality content, such as streaming video or audio, the demands on the network capacity of the Internet will continue to grow at an almost exponential rate. The real key to ensuring the continued proliferation and success of the Internet will be providing reliable, high-speed access to individual users anytime and anywhere: whether they're at home, in the car, or using a wireless device.