Evolution of Internet

The Internet has its roots in a networking project started by the Pentagon's Advanced Research Projects Agency (ARPA), an agency of the U.S Department of Defense. ARPA's goal was to build a network that (1) allowed scientists at different physical locations to share information and work together on military and scientific projects and (2) could function even if part of the network were disabled or destroyed by a disaster such as a nuclear attack. That network, called ARPANET, became functional in September 1969, linking scientific and academic researchers across the United States.

 The original ARPANET consisted of four main computers, one each located at the University of California at Los Angeles, the University of California at Santa Barbara, the Stanford Research Institute, and the University of Utah. Each of these computers served as a host on the network. A host, more commonly known today as a server, is any computer that provides services and connections to other computers on the network. Hosts often use high-speed communications to transfer data and messages over a network.

 As researchers and others realized the great benefit of using ARPANET to share data and information, ARPANET underwent phenomenal growth. By 1984, ARPANET had more than 1,000 individual computers linked as hosts. Today, more than 550 million hosts connect to the Internet.

 Some organizations connected entire networks to ARPANET to take advantage of its high-speed communications. In 1986, the National Science Foundation (NSF) connected its huge network of five supercomputer centers, called NSFnet, to ARPANET. This configuration of complex networks and hosts became known as the Internet.

 Until 1995, NSFnet handled the bulk of the communications activity, or traffic, on the Internet. In  1995, NFSnet terminated its network on the Internet and resumed its status as a research network.

 Today, the Internet consists of many local, regional, national, and international networks. Numerous corporations, commercial firms, and other companies such as IBM provide networks to handle Internet traffic. Both public and private organizations own networks on the Internet. These networks, along with telephone companies such as Verizon and AT&T, cable and satellite companies, and the government, all contribute toward the internal structure of the Internet.

 Each organization on the Internet is responsible only for maintaining its own network. No single person, company, institution, or government agency controls or owns the Internet. The World Wide Web Consortium (W3C), however, oversees research and sets standards and guidelines for many areas of the Internet. The mission of the W3C is to contribute to the growth of the Web. More than 350 organizations from around the world are members of the W3C, advising, defining standards, and addressing other issues.

Internet2

 Internet2 is a not-for-profit research and development project that connects more than 200 universities and 115 companies via a high-speed private network. Founded in 1996, the goal of Internet2 is to develop and test advanced network technologies that will benefit Internet users in the short-term future. These technologies require an extremely high-speed network that exceeds the capabilities of today's Internet and networks. Examples of previous Internet2 projects that are now mainstream include telemedicine, digital libraries (online books, magazines, music, movies, speeches, etc.), and faster Internet services. Current Internet2 projects include interactive high-definition video and enhanced detection and resolution of network problems.

Connecting to the Internet

 Many home and small business users connect to the Internet via high-speed broadband Internet service. With broadband Internet service, your computer or mobile device usually is connected to the Internet the entire time it is powered on. Examples of broadband Internet service include cable, DSL, fiber, radio signals, and satellite.

• Cable Internet service provides high-speed Internet access through the cable television network via a cable modem.
• DSL (digital subscriber line) provides high-speed Internet connections using regular copper telephone lines.
• Fiber to the Premises (FTTP) uses fiber-optic cable to provide high-(speed Internet access to home and business users.
• Fixed wireless provides high-speed Internet connections using a dish-shaped antenna on your house or business to communicate with a tower location via radio signals.
• A cellular radio network offers high-speed Internet connections to devices with built-in compatible technology or computers with wireless modems.
• A Wi-Fi (wireless fidelity) network uses radio signals to provide high-speed Internet connections to compatible or properly equipped wireless computers and devices.
• Satellite Internet service provides high-speed Internet connections via a satellite dish that communicates with a satellite modem.

 Employees and students typically connect their computers to the Internet through a business or school network. The business or school network connects to a high-speed broadband Internet service.

 Many home users set up a Wi-Fi network, which sends signals to a communications device that is connected to a high-speed Internet service such as cable or DSL. Instead of using broadband Internet service, however, some home users connect to the Internet via dial-up access, which is a slower-speed technology. Dial-up access takes place when the modem in your computer connects to the Internet via a standard telephone line that transmits data and information using an analog (continuous wave pattern) signal. Users may opt for dial-up access because of its lower price or because broadband access is not available in their area.

 Mobile users access the Internet using a variety of Internet services. Most hotels and airports provide wired or wireless Internet services, such as Wi-Fi networks, allow mobile users to connect easily to the Internet with notebook computers, smart phones, and other mobile devices while away from a telephone, cable, or other wired connection. Many public locations, such as airports, hotels, schools, shopping malls, and coffee shops, are hot spots that provide Wi-Fi Internet connections to users with mobile computers or devices. At public locations, you may be required to agree to terms of service, obtain a password (for example, from the hotel's front desk), or perform some other action in order to connect to the Internet. Some cities provide free Wi-Fi Internet connections to all residents.

Access Providers

 An access provider is a business that provides individuals and organizations access to the Internet free or for a fee. For example, some Wi-Fi network provide free access while others charge a per use fee. Other access providers often charge a fixed amount for an Internet connection, offering faster speeds or more services for higher rates. Many Internet access providers offer services such as news, weather, financial data, games, travel guides, e-mail, photo communities, and online storage to hold digital photos and other files.

 Access providers are categorized as regional or national ISPs, online service providers, and wireless Internet service providers.

 An ISP (Internet service provider) is a regional or national access provider. A regional ISP usually provides Internet access to a specific geographic area. A national ISP is a business that provides Internet access in cities and towns nationwide. For dial-up access, some national ISPs provide both local and tool-free telephone numbers. Due to their larger size, national ISPs usually offer more services and have a larger technical support staff than regional ISPs. Examples of national ISPs are AT&T and EarthLink.

In addition to providing Internet access, an online service provider (OSP) also has many members-only features such as instant messaging or their own customized version of a Web browser. The more popular OSPs are AOL (America Online) and MSN (Microsoft Network). AOL  differs from many OSPs in that it provides gateway functionality to the Internet services to which members have access. AOL also provides free access to its services to any user with a broadband Internet connection.

 When selecting an ISP or OSP for dial-up access, ensure it provides at least one local telephone number. Otherwise, long-distance telephone charges will apply for the time you connect to the Internet.

 A wireless Internet service provider, sometimes called a wireless data provider, is a company that provides wireless Internet access to desktop and notebook computers and mobile devices, such as smart phones and portable media players, with built-in wireless capability (such as Wi-Fi) or to computers using wireless modems or wireless access devices. Wireless modem, which usually are in the form of a USB flash drive or a card that inserts in a slot in a computer or mobile device, generally dial a telephone number to establish a connection with the wireless Internet service provider. An antenna on or built into the computer or device, wireless modem, or wireless access device typically sends signals through the airwaves to communicate with a wireless Internet service provider. Some examples of wireless Internet service providers include AT&T, Boingo Wireless, Sprint Broadband Direct, T-Mobile, and Verizon Wireless.

How Data and Information Travel the Internet

 Computers connected to the Internet work together to transfer data and information around the world using servers and clients and various wired and wireless transmission media. On the Internet, your computer is a client that can access data, information, and services on a variety of servers.

 The inner structure of the Internet works much like a transportation system. Just as interstate highways connect major cities and carry the bulk of the automotive traffic across the country, several main transmission media carry the heaviest amount of traffic on the Internet. These major carriers of network traffic are known collectively as the Internet backbone.

 In the United States, the transmission media that make up the Internet backbone exchange data and information at several different major cities across the country. That is, they transfer data and data and information from one network to another until reaching the final destination.

Internet Address

 The Internet relies on an addressing system much like the postal service o send data and information to a computer at a specific destination. An IP Address, short for Internet Protocol address, is number that uniquely identifies each computer or device connected to the Internet.
 The IP address usually consists of four groups of numbers, each separated by a period. The number in each group is between 0 and 255. For example, the numbers 72.14.207.99 are an IP address. In general, the first portion of each IP address identifies the network and the last portion identifies the specific computer.

 These all-numeric IP addresses are difficult to remember and use. Thus, the Internet supports the use of a text name that represents one or more IP addresses. A domain name is the text version of an IP address. As with an IP address, the components of a domain name are separated by periods.

 The text in the domain name up to the first period identifies the type of Internet server.

 Every domain name contains a top-level domain (TLD), which is the last section of the domain name. A generic TLD (gTLD), such as the com, identifies the type of organization associated with the domain. The Internet server and gTLD portions of a domain name often are not required.

 The organization that assigns and controls top-level domains is the Internet Corporation for Assigned Names and Numbers (ICANN). For TLDs such as biz, com, info, name, net, and org, you register for a domain name from a registrar, which is an organization that sells and manages domain names.

For international Web sites outside the United States, the domain name also includes a country cod TLD (ccTLD), which is a two-letter country code, such as au for Australia. For example, www.philips.com.au is the domain name for Philips Autralia. Some smaller countries have granted use of their ccTLDs for commercial purposes such as tv (Tuvalu) for the television/entertainment industry.

 The domain name system (DNS) is the method that the Internet uses to store domain names and their corresponding IP addresses. When you specify a domain name, a DNS server translates the domain name to its associated IP address so that data and information can be routed to the correct computer. A DNS server is an Internet server that usually is associated with an Internet access provider.

 The growth of the Internet has led to a shortage of IP addresses. Thus, a new IP addressing scheme, called IPv6, may increase the number of available IP addresses.