The Internet has revolutionized many aspects of our daily lives. Daily many people send email, pay bills, read or watch news and gather any sort of information in seconds by using the Internet. It is also useful to students for research purpose, for chatting with friends and online shopping. The Internet has brought a wealth of information to our fingertips and organized it for our use.

A network is a group of connected, communicating devices such as computers and printers. An internet is two or more networks that can communicate with each other. The most notable internet is called the Internet, a collaboration of more than hundreds of thousands interconnected networks. Private individuals as well as well as various organizations such as government agencies, schools, research facilities, corporations, and libraries in more than 100 countries use the Internet. Even though currently millions of people are using it, this amazing communication system came into being only in 1969.

APRANET
In the mid 1960s, mainframe computers in research organizations were stand-alone devices. Computers from different manufacturers were unable to communicate with each other. The Advanced Research Project Agency (ARPA) in the Department of defense (DOD) was interested in finding a way to connect computers together so that the researchers they funded could share their findings, thereby reducing costs and eliminating duplication of effort.

In 1967, at an Association of Computing Machinery (ACM) meeting, ARPA presented its ideas for ARPANET, a small network of connected computers. The idea was that each host computer (not necessarily from same manufacturer) would be attached to a specialized computer, called an “interface message processor” (IMP). The IMPs, in turn, would be connected to each other. Each IMP had to be able to communicate with other IMPs as well as with its own attached host.

By 1969, ARPANET was a reality. Four nodes, at the University of California at Los Angeles (UCLA), the University of California at Santa Barbara (UCSB), Stanford Research Institute (SRI), and the University of Utah were connected via the IMPs to form a network. Software called the “Network Control Protocol” (NCP) provided communication between the hosts.

Birth of the Internet
In 1972, Vint Cerf and Bob Kahn, both of whom were part of the core APRANET group, collaborated on what they called the “Internetting Project”. They wanted to link different networks together so that a host on one network could communicate with a host on a second, different network. There were many problems to overcome: diverse packet sizes, diverse interfaces, and diverse transmission rates, as well as differing reliability requirements. Cerf and Kahn devised the idea of a device called a “gateway” to serve as the intermediary hardware to transfer packets from one network to another.

TCP/IP
Cerf and Kahn’s landmark 1973 paper outlined the protocols to achieve end-to-end delivery of packets. This was a new version of NCP. This paper on transmission control protocol (TCP) included concepts such as encapsulation, the datagram, and the functions of a gateway. A radical idea was the transfer of responsibility for error correction from the IMP to the host machine. This ARPA Internet now became the focus of the communication effort. Around this time responsibility for the ARPANET was handed over to the Defense Communication Agency (DCA).

In October 1977, an internet consisting of three different networks (ARPANET, packet radio, and packet satellite) was successfully demonstrated. Communication between networks was now possible.

Shortly thereafter, authorities made a decision to split TCP into two protocols: Transmission Control Protocol (TCP) and Internetworking Protocol (IP). IP would handle datagram routing while TCP would be responsible for higher level functions such as segmentation, reassembly, and error detection. The internetworking protocol became known as TCP/IP.

In 1981, under a DARPA contract, UC Berkeley modified the UNIX operating system to include TCP/IP. This inclusion of network software along with a popular operating system did much to further the popularity of networking. The open (non-manufacture-specific) implementation on Berkeley UNIX gave every manufacturer a working code base on which they could build their products.

In 1983, authorities abolished the original ARPANET protocols and TCP/IP became the official protocol for the ARPANET. Those who wanted to use the Internet to access a computer on a different network had to be running TCP/IP.

MILNET
In 1983, ARPANET split into two networks: MILNET for military users and ARPANET for nonmilitary users.

CSNET
Another milestone in Internet history was the creation of CSNET in 1981. CSNET was a network sponsored by the National Science Foundation (NSF). The network was conceived by universities that were ineligible to join ARPANET due to an absence of defense ties to DARPA. CSNET was a less expensive network; there were no redundant links and the transmission rate was slower. It featured connections to ARPANET and Telenet, the first commercial packet data service.

By the middle 1980s, most U.S. universities with computer science departments were part of CSNET. Other institutions and companies were also forming their own networks and using TCP/IP to interconnect. The term “Internet”, originally associated with government funded connected networks, now referred to the connected networks using TCP/IP protocols.

NSFNET
With the success of CSNET, the NSF, in 1986, sponsored NSFNET, a backbone that connected five supercomputer centers located throughout the United States. Community networks were allowed access to this backbone, a T1 line with a 1.544 Mbps data rate, thus providing connectivity throughout the United States.

In 1990, ARPANET was officially retired and replaced by NSFNET. In 1995, NSFNET reverted back to its original concept of a research network.

ANSNET
In 1991, the U.S. government decided that NSFNET was not capable of supporting the rapidly increasing Internet traffic. Three companies, IBM, Merit and MCI, filled the void by forming a nonprofit organization called Advanced Network and Services (ANS) to build a new, high-speed Internet backbone called ANSNET.

The Internet Today
The Internet today is not a simple hierarchical structure. It is made up of many wide and local area networks joined by connecting devices and switching stations. It is difficult to give an accurate representation of the Internet because it is continuously changing – new networks are being added, existing networks need more addresses, and networks of defunct companies need to be removed. Today most end users who want Internet connection use the services of Internet service providers (ISPs). There are international service providers, national service providers, regional service providers, and local service providers. The Internet today is run by private companies, not the government.

International Service Providers
At the top of the hierarchy are the international service providers that connect nations together.

National Service Providers (NSPs)
National Service Providers (NSPs) are backbone networks created and maintained by specialized companies. There are many NSPs operating in North America; some of the most well-known are SprintLink, PSINet, UUNet Technology, AGIS, and internet MCI. To provide connectivity between the end users, these backbone networks are connected by complex switching stations (normally run by a third party) called network access points (NSPs). Some NSP networks are also connected to each other by private switching stations called peering points. NSPs normally operate at a high data rate (up to 600 Mbps).

Regional Internet Service Providers
Regional internet service providers or regional ISPs are small ISPs that are connected to one or more NSPs. They are at the third level of hierarchy with a lesser data rate.

Local Internet Service Providers
Local internet service providers provide direct service to the end users. The local ISPs can be connected to regional ISPs or directly to NSPs. Most end users are connected to the local ISPs. Note that in this sense, a local ISP can be a company that just provides Internet service, a corporation with a network to supply services to its own employees, or a nonprofit organization, such as a college or a university that runs its own network. Each of these can be connected to a regional or national service provider.

Time Line
The following is a list of important Internet events in chronological order:
• 1969: Four-node ARPANET
• 1970: ARPA hosts implement NCP
• 1973: Development of TCP/IP suite begins
• 1977: An internet tested using TCP/IP.
• 1978: UNIX distributed to academic/research sites.
• 1981: CSNET established.
• 1983: TCP/IP becomes the official protocol for ARPANET.
• 1983: MILNET was born.
• 1986: NSFNET established.
• 1990: ARPANET decommissioned and replaced by NSFNET.
• 1995: NSFNET goes back to being a research network.
• 1995: Companies known as Internet Service Providers (ISPs) started.

Growth of the Internet
The internet has grown tremendously. In just a few decades, the number of network has increased from tens to hundreds of thousands. Concurrently, the number of computers connected to the networks has grown from hundred to hundreds of millions. The Internet is still growing. Factors that have an impact on this growth include the following:

• New Protocols: New protocols need to be added and obsolete ones need to be removed. For example, a protocol superior in many respects to IPv4 has been approved as a standard but not yet fully implemented.
• New Technology: New technologies are under development that will increase the capacity of networks and provide more bandwidth to the Internet’s users.
• Increasing Use of Multimedia: It is predicted that the Internet, once just a vehicle to share data, will be used more and more for multimedia (audio and video).

PROTOCOLS AND STANDARDS
Protocols
In computer networks, communication occurs between entities in different systems. An entity is anything capable of sending or receiving information. However, two entities cannot simply send bit streams to each other and expect to be understood. For communication to occur, the entities must agree on a protocol. A protocol is a set of rules that governs data communication. A protocol defines what is communicated, how it is communicated, and when it is communicated. The key elements of a protocol are syntax, semantics, and timing.

• Syntax: Syntax refers to the structure or format of the data, meaning the order in which they are presented. For example, a simple protocol might expect the first 8 bits of data to be the address of the sender, the second 8 bits to be the address of the receiver, and the rest of the stream to be the message itself.

• Semantics: Semantics refers to the meaning of each section of bits. How is a particular pattern to be interpreted, and what action is to be taken based on that interpretation? For example, does an address identify the route to be taken or the final destination of the message?

• Timing: timing refers to two characteristics: when data should be sent and how fast it can be sent. For example, if a sender produces data at 100 Megabits per second (Mbps) but the receiver can process data at only 1 Mbps, the transmission will overload the receiver and data will be largely lost.

Standards
Standards are essential in creating and maintaining an open and competitive market for equipment manufacturers and also in guaranteeing national and international inter-operability of data and telecommunication technology and processes. They provide guidelines to manufacturers, vendors, government agencies, and other service providers to ensure the kind of interconnectivity necessary in today’s marketplace and in international communication.

Data communication standards fall into two categories: “de facto” (meaning “by fact” or “by convention”) and “de jure” (meaning “by law” or “by regulation”).
• De facto: Standards that have not been approved by an organized body but have been adopted as standards through widespread use are de facto standards. De facto standards are often established originally by manufacturers that seek to define the functionality of a new product or technology.
• De jure: De jure standards are those that have been legislated by an officially recognized body.

STANDARDS ORGANIZATIONS
Standards are developed through cooperation of standards creation committees, forums, and government regulatory agencies.

Standards Creation Committees
While many organizations are dedicated to the establishment of standards, data telecommunications in North America rely primarily on those published by the following:

• International Standards Organization (ISO): The International Standards Organization (ISO; also referred to as the International Organization for Standardization) is a multinational body whose membership is drawn mainly from the standards creation committees of various governments throughout the world. Created in 1947, the ISO is an entirely voluntary organization dedicated to worldwide agreement on international standards. With a membership that currently includes representative bodies from 82 industrialized nations, it aims to facilitate the international exchange of goods and services by providing models for compatibility, improved quality, increased productivity, and decreases prices. The ISO is active in developing cooperation in the realms of scientific, technological, and economic activity. The United States is represented in the ISO by ANSI.

• International Telecommunication Union-Telecommunication Standards Sector (ITU-T): By the early 1970s. A number of countries were defining national standards for telecommunications but there were still little international compatibility. The United Nations responded by forming, as part of its International Telecommunication union (ITU), a committee, the Consultative Committee for International Telegraphy and Telephony (CCITT). This committee was devoted to the research and establishment of standards for telecommunication in general and phone and data system in particular. On March 1, 1993, the name of this committee was changed to the International Telecommunications Union-Telecommunications Standard Sector (ITU-T).

• American National Standards Institute (ANSI): Despite its name, the American National Institute (ANSI) is a completely private, nonprofit corporation not affiliated with the U.S federal government. However, all ANSI activities are undertaken with the welfare of the United States and its citizens occupying primary importance. ANSI’s expresses aims include serving as the national coordinating institution for voluntary standardization in the United States, furthering the adoption of standards as a way of advancing the U.S. economy, and ensuring the participation and protection of the public interests. ANSI members include professional societies, industry associations, governmental and regulatory bodies, and consumer groups.

• Institute of Electrical and Electronics Engineers (IEEE): The institute of Electrical and Electronics Engineers (IEEE) is the largest professional engineering society of the world. International in scope, it aims to advance theory, creativity, and product quality in the fields of electrical engineering, electronics, and radio as well as in all related branches of engineering. As one of its goals, the IEEE oversees the development and adoptions of international standards for computing and communication.

• Electronic Industries Association (EIA): aligned with ANSI, the electronic Industries Association (EIA) is a nonprofit organization devoted to the promotion of electronics manufacturing concerns. Its activities include public awareness education and lobbying efforts in addition to standards development. In the field of information technology, the EIA has made significant contributions by defining physical connection interfaces and electronic signaling specifications for data communication.

Forums
Telecommunications technology development is moving faster than the ability of standards committees to ratify standards. Standards committees are procedural and by nature slow moving. To accommodate the need for working models and agreements and to facilitate the standardization process, many special-interest groups have developed forums made up of representatives from interested corporations. The forums work with universities and users to test, evaluate, and standardize new technologies. By concentrating their efforts on a particular technology, the forums are able to speed acceptance and use of those technologies in the telecommunication community. The forums present their conclusion to the standards bodies. Some important forums for the telecommunication industry are Frame Relay Forum and ATM Forum.

Regulatory Agencies
All communications technology is subject to regulation by government agencies such as the Federal Communications Commission in the United States. The purpose of these agencies is to protect the public interest by regulating radio, television, and wire communications.
• Federal Communications Commission (FCC): The Federal Communications Commission (FCC) has authority over interstate and international commerce as it relates to communication.

INTERNET STANDARDS
An Internet standard is a thoroughly tested specification that is useful to and adhered to by those who work with the Internet. It is a formalized regulation that must be followed. There is a strict procedure by which a specification attains Internet standard status. A specification begins as an Internet draft. An Internet draft is a working document (a work in progress) with no official status and a six-month lifetime. Upon recommendation from the Internet authorities, a draft may be published as a Request for Comment (RFC). Each RFC is edited, assigned a number, and made available to all interested parties.

RFCs go through maturity levels and are categorized according to their requirement level. An RFC, during its lifetime, falls into one of six maturity levels: proposed standard, draft standard, Internet standard, historic, experimental, and informational.

INTERNET ADMINISTRATION
The Internet with its root primarily in the research domain has evolved and gained a broader user base with significant commercial activity. Various groups that coordinate Internet issues have guided this growth and development.

Internet Society (ISOC)
The Internet Society (ISOC) is an international, nonprofit organization formed in 1992 to provide support for the Internet process. ISOC accomplishes this through maintaining and supporting other Internet administrative bodies such as IAB, IETF, IRTF, and IANA. ISOC also promotes research and other scholarly activities relating to the Internet.

Internet Architecture Board (IAB)
The Internet Architecture Board (IAB) is the technical advisor to the ISOC. The main purposes of the IAB are to oversee the continuing development of the TCP/IP Protocol Suite and to serve in a technical advisory capacity to research members of the Internet community. IAB accomplishes this through its two primary components, the Internet Engineering Task Force (IETF) and the Internet Research Task Force (IRTF). Another responsibility of the IAB is the editorial management of the RFCs. IAB is also the external liaison between the Internet and other standards organization and forums.

Internet Engineering Task Force (IETF)
The Internet Engineering Task Force (IETF) is a forum of working groups managed by the Internet Engineering Steering Group (IESG). IETF is responsible for identifying operational problems and proposing solutions to these problems. IETF also develops and reviews specifications intended as Internet standards. The working groups are collected into areas, and each area concentrates on a specific topic. Currently nine areas have been defined, although this is by no means a hard and fast number. The areas are:
1. Application
2. Internet protocols
3. Routing
4. Operations
5. User services
6. Network management
7. Transport
8. Internet protocol next generation (Ipng)
9. security

Internet Research Task Force (IRTF)
The Internet Research Task Force (IRTF) is a forum of working groups managed by the Internet Research Steering Group (IRSG). IRTF focuses on long-term research topics related to Internet protocols, applications, architecture, and technology.

Internet Assigned Numbers Authority (IANA) and Internet Corporation for Assigned Names and Numbers (ICANN)

The Internet Assigned Numbers Authority (IANA), supported by the U.S. government, was responsible for the management of Internet domain names and addresses until October 1998. At that time the Internet Corporation for Assigned Names and Numbers (ICANN), a private nonprofit corporation managed by an international board, assumed IANA operations.

Network information Center (NIC)
The Network information Center (NIC) is responsible for collecting and distributing information about TCP/IP protocols.