2. HISTORY OF THE INTERNET

The Internet is a very complex entity of more than 10 million hosts connecting over 95,000 networks. To fully describe what the Internet consists of today, it is necessary to look at how the Internet began and evolved to its current state. The roots of the technology employed by today's Internet are found by analyzing its evolution. This section provides a detailed description of the history of the Internet beginning with the initial work performed by the Defense Advanced Research Projects Agency (DARPA) in 1969 to the recent commercialization of the Internet and the dissolution of the National Science Foundation Network (NSFNET) backbone in 1995. Exhibit 2-1 shows a timeline of the history of the Internet that this section will discuss in detail.

Exhibit 2-1
Internet Timeline
[click here to view exhibit 2-1]

The inception of the Internet can be traced to 1969 when DARPA was commissioned by the United States Department of Defense (DoD) to develop a communications system that would be survivable in the face of enemy attacks including nuclear war. In addition, the network should allow military and academic researchers to collaborate on research projects and share computer processors across the country. In response to this direction, DARPA, later renamed ARPA, set up a network consisting of the following four nodes:
* University of California at Los Angeles
* Stanford Research Institute
* University of California at Santa Barbara
* University of Utah.

ARPA used this four-node network, referred to as ARPANET, to experiment with the linkage to be used between DoD and military research contractors.

In 1970, ARPA began researching packet switched technology. The goal of this technology was to decentralize the network by giving all nodes on the network equal authority to transmit and receive packets across the network. The route each packet took to its destination was unimportant as long as it reached its destination. Thus, packet switching technology was effective when network connections were unreliable. This packet switching technology, employed by ARPA during the seventies, was known as the Network Control Protocol (NCP). By the end of 1971, there were 15 nodes connecting 23 hosts to ARPANET.

In 1973, ARPA began the "Internetting" project. The goal of this project was to develop a protocol that could seamlessly pass information between different networks. This project culminated in 1977 in a demonstration of networking through various media including satellite, radio, telephone and Ethernet. The protocol developed in this project formed the basis for the Transmission Control Protocol and Internet Protocol (TCP/IP), where IP handles the addressing of the individual packets while TCP coordinates the proper transmission of information.

By the end of 1982, ARPA established TCP/IP as the protocol suite for the ARPANET, requiring that all nodes connecting to ARPANET use TCP/IP. Additionally, DoD declared that TCP/IP was to be its standard protocol. The official cutover from NCP to TCP/IP was executed on January 1, 1983. Aiding this transition was the incorporation of TCP/IP into Version 4.2 of Berkeley Standard Distribution of UNIX. This version of the UNIX operating system was free to anyone who wanted it, thus ensuring a wide deployment for TCP/IP. The marriage of TCP/IP and UNIX began a long-standing affiliation between the Internet and the UNIX operating system that continues today.

Another major event in 1983 was the division of ARPANET into two networks: ARPANET and MILNET. MILNET was to be used for military specific communications, whereas ARPANET was to continue its research and development in networking computers. MILNET was integrated with the Defense Data Network created in 1982. The funding for ARPANET was provided by Defense Advanced Research Projects Agency (DARPA). By 1984, the number of hosts connecting to the ARPANET was more than 1,000.

While the ARPANET was undergoing major changes, another significant event in the history of the Internet occurred. In 1979, representatives from DARPA and the NSF and computer scientists from several universities met to establish a Computer Science Department research computer network (CSNET). One of the driving forces for the establishment of CSNET was the concern that computing facilities located at universities not connected to ARPANET did not have the same advantages in research and staff and student recruitment as those who were connected. In 1981, CSNET was fully operational through money granted by NSF.

Although designed initially to be a standalone network, CSNET later incorporated a gateway connection to the ARPANET. In the summer of 1980, a DARPA scientist proposed the interconnection of the not yet established CSNET and ARPANET using protocols that would provide services and the seamless transmission of information between users regardless of the type of network. This set of protocols was TCP/IP. The gateway connection between the two networks was established in 1983.

In 1986, the NSF created the NSFNET. The purpose of this network was to provide high-speed communications links between five major supercomputer centers located across the United States. Although ARPANET was flourishing, its 56-Kbps backbone and network topology could not fulfill the demand for high-speed networking required by multiple research projects. The goal of the NSFNET was to provide a reliable environment for the U.S. research and education community and access to the major supercomputing centers. The NSFNET essentially duplicated the functionality of the ARPANET. NSF chose TCP/IP as the standard protocol for its new network. This new network ultimately led to the downfall of ARPANET. In 1990, ARPANET was formally retired.

The infrastructure of the NSFNET was a three-tier hierarchical structure:
* National backbone
* Regional networks
* Local area networks (LAN).

The original backbone of the NSFNET, depicted in Exhibit 2-2, consisted of a 56-Kbps network. This backbone network is considered the basis of what is now called the Internet. Regional networks hung off the backbone network and provided services to LANs at education and research facilities. Universities and research associations combined to form the regional networks, which in turn would aggregate their traffic and "hand it off" to the NSFNET backbone. Exhibit 2-3 depicts the three-tier structure implemented in the NSFNET throughout its existence.

Exhibit 2-2
Original NSFNET Backbone
[click here to view exhibit 2-2]

Source: NSF

Exhibit 2-3
NSFNET Three Tier Infrastructure (1986 - 1995)
[click here to view exhibit2-3]

Because NSFNET's primary focus was for nonprofit research and development by universities and research groups, NSF instituted an "acceptable use" policy that restricted the use of the NSFNET to noncommercial activities. Additionally, NSF offered financial help to those regional networks, composed of university and research facility LANs, who wished to connect to the NSFNET backbone.

By 1987, the NSFNET outgrew its existing capacity. NSF awarded a five-year contract to Merit, the Michigan state networking organization, with MCI and IBM. The purpose of this contract was to transition the NSFNET backbone to T1 links and provide several access points around the country. Merit's role was to manage the backbone including routing, whereas IBM provided the routing equipment and MCI provided the trunk lines. The transition to a T1 backbone was completed in 1988. By the end of the 1980s, more than 100,000 hosts from 17 countries worldwide were connecting to the NSFNET. Exhibit 2-4 depicts the T1 backbone of the NSFNET in 1988.

Exhibit 2-4
1988 T1 NSFNET Backbone
[click here to view exhibit 2-4]
Source: NSF

As the NSFNET grew, some organizations realized that providing services and functionality similar to that of the NSFNET without the access restrictions was a golden business opportunity. These organizations, experienced in providing regional network operations, seized the opportunity to set up their own nationwide backbone networks. Thus, the first commercial Internet service providers were created. These providers included Performance Systems (PSINet), and Alternet, which was generated from UUNet Technologies. The main focus of these networks was to provide the same functionality as the NSFNET, over their own networks, but without any access restrictions.

In 1991, the fourth year of the five-year contract, Merit, IBM and MCI formed a new nonprofit corporation, Advanced Networks and Services (ANS), which was given the operational responsibilities of the NSFNET. In June 1991, ANS announced it would provide commercial access to the Internet, thus nullifying the acceptable use policy. By broadening access to the Internet, ANS increased its efforts to expand connectivity and make the Internet a more powerful tool. The new evolving private commercial networks were hindering research, forcing researchers to spend time accessing several networks all in the name of science. With expanded commercial providers on the Internet, there was a single common network that increased a researcher's ability to find any information needed and focus on the research at hand. When NSF lifted its access restrictions in 1991, allowing commercial traffic on the NSFNET, ANS formed a for-profit subsidiary, ANS CO+RE (Commercial + Research & Education), to provide full commercial traffic across the backbone. Once the "acceptable use" policy had been abolished, PSINet, UUNet Technologies, and General Atomics (CERFnet) created the Commercial Internet Exchange (CIX). CIX was a traffic exchange point between the NSFNET and the commercial Internet service providers networks.

The other major event that occurred in 1991 was the transition of the NSFNET backbone from T1 links to T3. This transition, like the initial transition from 56-Kbps to T1 links in 1988, was because of the capacity of the backbone network could not meet the traffic loads. Although this transition required new routing equipment and interfaces and, at times, proved to be technically challenging, it was accomplished with relative ease. This was due to the fact that the same organizations who were managing the old T1 backbone were responsible for implementing and overseeing the new T3 backbone network. Additionally, the T1 backbone still existed as a backup if the new network failed. Exhibit 2-5 depicts the T3 NSFNET backbone as of 1992.

In 1992, Vice President Al Gore drafted legislation that proposed a National Research and Education Network (NREN). This new network would consist of T3 links (separate from those making up the NSFNET backbone) and would connect all schools, libraries, etc., for a cost of over $2 billion. Even though the legislation was passed, no new network ever came into existence. The NREN effort did, however, succeed in sparking a greater interest in the Internet.

Exhibit 2-5
1992 T3 NSFNET Backbone

[click here to view exhibit2-5]
Source: NSF

The new public Internet coincided with the release of the first Microsoft Windows version of Mosaic in 1993. Mosaic, developed by the University of Illinois at Urbana-Champaign, was an X-Windows interface to the World Wide Web (WWW). The concept of the WWW was started in 1989 in Switzerland as a means to easily share information among researchers in high-energy particle physics. In 1991, the first WWW server came into existence, but without any client software. The introduction of the first interface to WWW included the capability to navigate through the Web via the mouse. Today's Web browsers, such as Netscape, include File Transfer Protocol (FTP), E-mail, Telnet, and many more capabilities. The use of a graphical interface to access the Internet has played a significant role in the popularity growth of the network because it allowed access to the Internet without having knowledge or possession of the UNIX operating system.

While the look and feel of the Internet was undergoing changes, NSF, in 1992, began to question its role in the network. NSF observed that its backbone network was operating in conjunction with several commercial nationwide backbone networks. Essentially, NSF was paying for users to access its network, and thus the Internet, whereas the other commercial service providers were being paid for access to theirs. Although in 1991 the NSF had notified the regional networks that they would have to become self-sustaining, it was 1992 before the NSF took action. The NSF began considering ways in which it could successfully pull out of the Internet arena with little disruption to the Internet while continuing its commitment to the education and research community.

With the five-year contract between the NSF and Merit drawing to a close, Merit was granted an 18-month extension (beyond the original October 1992 expiration date) to allow the NSF time to work out how to transition its backbone network into a new structure. This work culminated in a solicitation for proposals (Solicitation 93-52) in the following four areas that compose the new national Internet structure:
* Network Access Points (NAP)
* Routing Arbiter
* Regional network provider awards
* A very high-speed Backbone Network Service (vBNS).

The NAPs act as interconnection points where commercial Internet service providers can meet and exchange traffic. The NSF believed that without such interconnect points, backbone providers would likely establish their own independent bilateral connect points that would stifle the NSF's plan for full connectivity for the research and education community. The NAP manager contracts were awarded to the following:
* Sprint, for a New York NAP
* Metropolitan Fiber Systems (MFS) Datanet for a Washington DC NAP
* Bellcore and Ameritech for a Chicago NAP
* Bellcore and Pacific Bell for a California NAP.

The Routing Arbiter is an independent group that operates route servers at each NAP. The transfer of traffic among the backbone providers that meet at the NAPs is facilitated by route databases contained in the route servers. These databases contain routing information and policy requirements for each backbone provider and therefore indicate to which provider the incoming information should be sent. This contract was awarded to Merit and the Information Sciences Institute (ISI) at the University of Southern California, which together make up the Routing Arbiter group.

With the dissolution of the NSFNET, and the introduction of NAPs and commercial traffic, access to the Internet by the NSF subsidized regional networks was no longer free. The commercial backbone providers were now paying a fee to interconnect with the NAPs and passing these charges to their users - the regional network providers. Therefore, the NSF decided to create the regional network provider contracts to alleviate the regional networks' initial shock of having to pay for Internet access. The awards provided the regional networks with annual NSF funding, with the funding declining to zero over a four-year period. The regional network providers would use the subsidy to pay the commercial Internet providers who were in turn required to connect to the NAPs. There were 17 contracts awarded to regional network providers for interregional connectivity.

The NSF also proposed to sponsor a new backbone, the vBNS, operating at a minimum speed of OC-3 (155 Mbps), to link the following five NSF supercomputer centers:
* Cornell Theory Center
* National Center for Atmospheric Research
* National Center for Supercomputing Applications
* Pittsburgh Supercomputing Center
* San Diego Supercomputing Center.

Unlike the general purpose NSFNET infrastructure, the vBNS functions as an advanced research laboratory, allowing research, development, and integration of new networking requirements, using technology beyond just IP routing. There is a strict acceptable use policy: the vBNS may only be used for meritorious high-bandwidth research activities and it may not be used for general Internet traffic. NSF entered into a five-year agreement with MCI to provide the vBNS.

During this five-year agreement, MCI is expected to participate in the development and use of advanced Internet routing technologies. At the end of the agreement, it is anticipated that technology will exist that will increase the transmission speeds beyond 2.2 Gbps. Additionally, the vBNS will act as an experimental platform for the development and testing of broadband Internet services and equipment. Exhibit 2-6 depicts the NSF's vBNS network.

Exhibit 2-6
The National Science Foundation vBNS Network
[click here to view exhibit 2-6]
Source: MCI

The result of NSF's solicitation for proposals was a new Internet structure. In April 1995, the NSFNET backbone was formally retired. At that time, 93 countries and more than 50,000 networks were connected by the NSFNET backbone. Exhibit 2-7 details the number of networks, by country, connected to the NSFNET backbone by the end of the project.

NSF's original task was to improve the previous NSFNET backbone, push the technology to new heights, and implement it on a national level. It was hoped that this would place a powerful tool in the hands of the research and education community, and create innovative use and applications. Its goals were accomplished: the NSFNET backbone connected most of the higher research and education community to a robust and reliable high-speed network and it served as the sole player in making the Internet industry.

The NSF's task will continue to evolve in two directions: 1) providing support for the research and education community by guaranteeing the availability of services, resources, and tools to keep the Internet connected, and 2) by continuing to push networking technology using the vBNS.

Exhibit 2-7
Countries and Networks Connected to NSFNET as of April 1995

Country Total Networks Country Total Networks Country Total Networks
Algeria 3 Greece 105 Norway 214
Argentina 27 Guam 5 Panama 1
Armenia 3 Hong Kong 95 Peru 44
Australia 1875 Hungary 164 Philippines 46
Austria 408 Iceland 31 Poland 131
Belarus 1 India 13 Portugal 92
Belgium 138 Indonesia 46 Puerto Rico 9
Bermuda 20 Ireland 168 Romania 26
Brazil 165 Israel 217 Russia 405
Bulgaria 9 Italy 506 Senegal 11
Burkina Faso 2 Jamaica 16 Singapore 107
Cameroon 1 Japan 1847 Slovakia 69
Canada 4795 Kazakhstan 2 Slovenia 46
Chile 102 Kenya 1 South Africa 419
China 8 Korea, South 476 Spain 257
Colombia 5 Kuwait 8 Swaziland 1
Costa Rica 6 Latvia 22 Sweden 415
Croatia 31 Lebanon 1 Switzerland 324
Cyprus 25 Liechtenstein 3 Taiwan 575
Czech Rep. 459 Lithuania 1 Thailand 107
Denmark 48 Luxembourg 59 Tunisia 19
Dominican Rep. 1 Macau 1 Turkey 97
Ecuador 85 Malaysia 6 Ukraine 60
Egypt 7 Mexico 126 Unit Arab Emirates 3
Estonia 49 Morocco 1 U. K. 1436
Fiji 1 Mozambique 6 United States 28470
Finland 643 Netherlands 406 Uruguay 1
France 2003 New Caledonia 1 Usbekistan 1
French Polynesia 1 New Zealand 356 Venezuela 11
Germany 1750 Nicaragua 1 Vietnam 1
Ghana 1 Niger 1 Virgin Islands 4
Source: Merit Network, Inc.

Return to the Table of Contents