The Internet

Internet History

Throughout the 1970s, a United States government organization called the Advanced Research Projects Agency (ARPA) funded several projects to explore network technology. One result of these efforts was the ARPANET, a WAN that eventually became known as the Internet. The Internet is a network of networks. The term Internet comes from the WAN concept of internetworking—connecting many smaller networks together.

From the mid 1980s through the present day, the Internet has grown incredibly. In 1983, there were fewer than 600 computers connected to the Internet. By the year 2000, that number had reached over 10 million. As more and more computers connect to the Internet, the task of keeping up with the larger number of users and heavier traffic has been difficult. New technologies have replaced the ARPANET several times since the initial development, each time providing more capacity and faster processing.

Protocol

A protocol is a set of rules that governs how two things communicate. The software that controls the movement of messages across the Internet must conform to a set of protocols called TCP/IP (pronounced by spelling out the letters, T-C-P-I-P). 

TCP/IP

TCP stands for Transmission Control Protocol, and IP stands for Internet Protocol. The IP software defines how information is formatted and transferred from the source to the destination. The TCP software handles problems such as pieces of information arriving out of their original order or information getting lost, which can happen if too much information converges at one location at the same time.

IP Address

Every computer connected to the Internet has an IP address that uniquely identifies it among all other computers on the Internet. An example of an IP address is 204.192.116.2. Fortunately, the users of the Internet rarely have to deal with IP addresses. The Internet allows each computer to be given a name. Like IP addresses, the names must be unique. The Internet name of a computer is often referred to as its Internet address. Two examples of Internet addresses are

            spencer.villanova.edu

 and     kant.gestalt-llc.com.

The first part of an Internet address is the local name of a specific computer. The rest of the address is the domain name, which indicates the organization to which the computer belongs. For example, villanova.edu is the domain name for the network of computers at Villanova University, and spencer is the name of a particular computer on that campus. Because the domain names are unique, many organizations can have a computer

The Internet is a wide-area network (WAN) that spans the globe. 

 Individual departments might be assigned subdomains that are added to the basic domain name to uniquely distinguish their set of computers within the larger organization. For example, the csc.villanova.edu subdomain is devoted to the Department of Computing Sciences at Villanova University.

The last part of each domain name, called a top-level domain (TLD), usually indicates the type of organization to which the computer belongs. The TLD edu indicates an educational institution. The TLD com refers to a commercial business. For example, gestalt-llc.com refers to Gestalt, LLC, a company specializing in software technologies. Another common TLD is org, used by nonprofit organizations. Many computers, especially those outside of the United States, use a TLD that denotes the country of origin, such as uk for the United Kingdom. Recently, in response to a diminishing supply of domain names, some new toplevel domain names have been created, such as biz, info, and name.

DNS

When an Internet address is referenced, it gets translated to its corresponding IP address, which is used from that point on. The software that does this translation is called the Domain Name System (DNS). Each organization connected to the Internet operates a domain server that maintains a list of all computers at that organization and their IP addresses. It works somewhat like telephone directory assistance in that you provide the name, and the domain server gives back a number. If the local domain server does not have the IP address for the name, it contacts another domain server that does. The Internet has revolutionized computer processing. Initially, the primary use of interconnected computers was to send electronic mail, but Internet capabilities continue to improve. One of the most significant uses of the Internet is the World Wide Web.