Internet Infrastructure

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Generally speaking, infrastructures are the frameworks or architectures that systems are made of. For example, a nation's transportation infrastructure consists of roadways, railroads, airports, ocean ports, and rivers. Although not as visible to the naked eye, the Internet also has an infrastructure consisting of many different elements, each of which plays a critical role in the delivery of information from one point to another.


Simply defined, the Internet is a very large network of many other computer networks. The United States Government played an important role in creating what eventually became the Internet during the 1960s. The Department of Defense Advanced Research Projects Agency (DARPA) funded early research into packet switching technology, which computer systems use to communicate. This approach differed from the way telephone systems transmitted data. Packet switching technology led to the development of ARPANET, the Internet's predecessor.

DARPA, the Defense Communications Agency, and Stanford University supported the development of important communication protocolscalled Transmission Control Protocol and Internet Protocol (TCP/IP)that define the way information is transmitted on the Internet. TCP/IP became the standard communication protocol used on ARPANET in January of 1983. Generally speaking, communication protocols like TCP/IP are the means by which devices understand and agree upon how and when they will share information with one another.

In 1990, ARPANET was succeeded by NSFNET, which the National Science Foundation created in 1987 to link university computer science departments across the United States. The NSF established regional networks that aggregated traffic from the universities and accordingly fed it into the "back-bone" of NSFNET. The universities that connected to the NFSNET backbone further connected other networks of colleges and individuals.

In 1995, the NSF did away with its backbone and turned what had been NSFNET over to the commercial sector. It created network access points (NAPs) that made it possible for telecommunication companies like MCI and Sprint to establish Internet backbones of their own, to which national or regional Internet Service Providers (ISPs) could connect. Organizations or individuals seeking Internet access then had to obtain it directly from a NAP, or subscribe to ISPs like America Online (AOL) with NAP access.


At the most rudimentary level of the Internet infrastructure are endless miles of telephone lines and fiber optic cable. These cables connect millions of individual users and businesses to other parties, transmitting data at varying speeds, depending on the types of cabling used. Another factor that affects the speed and quality of a user's connection is the means of connection, which include telephone modems; high-speed connection methods like cable modems, ISDN, DSL, and T1 lines; and company networks. According to the Strategis Group, high-speed residential Internet service was expected to surpass telephone dialup methods in the United States by 2005, at which time Strategis predicted there would be 36 million broadband subscribers.

It's easier to understanding how pieces of the Internet infrastructure work if one visualizes them transmitting data. The first step involved in sending or receiving data involves ISPs, which maintain racks upon racks of modems. Users connect to these modems in order to gain access to the ISP's network, which can vary in reach depending on the ISP's size. In the early 2000s, there were more than 7,000 ISPs throughout the world. The top 10 accounted for only 25 percent of total Internet access traffic. Once connected to an ISP, users then attempt to communicate by sending e-mail messages to other Internet users or by requesting Web pages or downloadable files from any number of servers located across the world. Servers are the computers used by individuals, companies, and other organizations to host Web sites, e-mail systems, or files that can be downloaded.

The process used to send and receive information across the world is more or less hidden to the user, and occurs in just seconds. In order for this to happen, a user on one ISP's network must be able to connect to users on another ISP's network, which may be located across the nation or across the globe. An exception to this would be if two users were located on the same ISP's network. ISPs connect to one another at NAPs, also called Internet exchanges (IX), which are major pieces of the Internet's backbone.

When the NSF opened the Internet to commercial enterprises in 1995, the first NAPs were located in Chicago; Pennsauken, New Jersey; Washington, D.C.; and San Francisco. These were operated by Ameritech, Sprint, Pac Bell, and MFS (a predecessor of MCI WorldCom). MFS later created two coastal access points called metropolitan area exchanges (MAE). By the early 2000s, there were more than 10 major access points throughout the United States. Sometimes ISPs make arrangements to establish direct connections between their networks. Known as private peering, this eliminates the need for relying on one of the major NAPs and helps to reduce congestion on the Internet.

Devices known as routers make sure that the packets of data sent from a computer on one ISP's network are sent to the intended machine on another local or wide-area network via the quickest, most efficient route, in accordance with communication protocols like TCP/IP. Just as the post office needs to know a street address before it can deliver a letter, routers need to know the address of the device to which information is being sent via the Internet. All devices communicating on the Internet, including servers used to host Web sites, have unique Internet Protocol (IP) addresses, which are four sets of numbers separated by decimals. Corresponding to numeric IP addresses are domain names, which are easier for humans to remember than long sequences of numbers. In the Web site address, .COM (like .ORG or .NET) is called the top-level domain and the word Yahoo is called the second-level domain. As the Internet evolved, a distributed database called the Domain Name System was created which contains all of the domain names and IP addresses associated with registered entities. Domain name servers located across the Internet are responsible for finding registered domain names and converting them to IP addresses so a connection can occur.


In addition to the technical pieces of the Internet infrastructure, there are several organizations that regulate different aspects of it, or that seek to improve its stability and functionality. The Internet Society is a professional society that "provides leadership in addressing issues that confront the future of the Internet, and is the organization home for the groups responsible for Internet infrastructure standards, including the Internet Engineering Task Force (IETF) and the Internet Architecture Board (IAB)." The society's mission is "to assure the open development, evolution, and use of the Internet for the benefit of all people throughout the world."

According to the IAB, that organization is a technical advisory group whose responsibilities include providing "oversight of the architecture for the protocols and procedures used by the Internet." It "acts as a source of advice and guidance to the Board of Trustees and Officers of the Internet Society concerning technical, architectural, procedural, and (where appropriate) policy matters pertaining to the Internet and its enabling technologies." The IETF is "a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet."

Several other organizations were involved in overseeing the Internet in the early 2000s. The American Registry for Internet Numbers (ARIN) was a nonprofit organization that administered and registered IP numbers for North America, South America, the Caribbean, and sub-Saharan Africa. Two other regional Internet registries, Reseaux IP Europeens Network Coordination Centre (RIPE NCC), and the Asia Pacific Network Information Centre (APNIC) were responsible for administration and registration for the rest of the world.

The Internet Corporation for Assigned Names and Numbers (ICANN) was a non-profit corporation "formed to assume responsibility for the IP address space allocation, protocol parameter assignment, domain name system management, and root server system management functions previously performed under U.S. Government contract by IANA and other entities." Domain names were assigned to people or organizations through a registration process performed by a number of different registrars accredited by ICANN. A company called Network Solutions was responsible for keeping track of registered domain names to avoid duplication.

Finally, the World Wide Web Consortium was an organization responsible for developing "interoperable technologies (specifications, guidelines, software, and tools) to lead the Web to its full potential as a forum for information, commerce, communication, and collective understanding," and the Cooperative Association for Internet Data Analysis (CAIDA) collected, monitored, and analyzed information about Internet traffic patterns and performance that was useful to researchers, educators, and policy makers in a variety of fields.


By the early 2000s, the size of and traffic on the Internet had grown significantly. Research from Telcordia revealed that the number of Internet hosts, which includes things like routers, mail servers, workstations, and Web servers, increased 45 percent during 2000, reaching 100 million. At that time, the global population of Internet users was estimated to be 350 million. Furthermore, the kinds of services, including e-commerce, being performed on the Internet were growing in sophistication and complexity. Corresponding to this were increasing demands in the areas of network quality and performance.

Concerns existed regarding the ability of the Internet, and the communication protocols it relied on, to support the world's users. This was complicated by the Internet's large size and the fact that no one entity controlled it. Therefore, the quality, integrity, and performance of different areas of the network varied, and control was distributed to many different entities throughout the world.

One infrastructure concern that existed in the early 2000s concerned the ability of routers to handle the skyrocketing number of entries to the Internet backbone's routing table, which stores information about all of the existing network destinations on the Internet. According to Network World, this was leading to instability in the Internet's backbone routing infrastructure. Part of the problem involved large companies that engaged in multi-homing, a practice of connecting to two ISPs at once in case service with one failed. Although this helped to ensure a more consistent Internet connection (which is critical for e-commerce companies), the practice required a separate listing in the routing table for each ISP used.

Another concern involved the burgeoning number of international users in developing nations without the sophisticated infrastructure found in Europe and the United States. In March of 2001, Information-Week reported that although 100 million computers were connected to the Internet, that figure represented less than two percent of the world's population. It also explained that 88 percent of Internet users lived in industrialized nations.

This placed increased demands on limited resources in developing nations. Telecordia's research found that while the ratio of Internet users to hosts was 2.4 to one in the United States, the number was as high as 100 to one in countries like India where, according to eMarketer, less than one percent of the adult population has Internet access. In India, 2.2 phone lines exist per 100 people, and many of those are substandard for connecting to the Internet at appropriate speeds. Inadequate infrastructures in areas like India and Latin America have strong implications for e-commerce. Forrester Research predicted that by 2004, 85 percent of online trade will occur in only 12 countries, led by the United States and Western Europe. Although wireless and satellite connections were one solution for nations where ground-based network infrastructures were virtually non-existent, the Internet's TCP/IP protocol didn't work consistently well via satellite, requiring special software to remedy the problem.


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SEE ALSO: ARPAnet; Connectivity, Internet; Digital Divide; History of the Internet and World Wide Web (WWW); ICANN (Internet Corp. for Assigned Names and Numbers); Internet Access, Tracking growth of; Internet Society (ISOC); Optical Switching; Photonics; World Wide Web Consortium (W3C)

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Internet Infrastructure

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