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Sistemas de Informação para Indústria© António Grilo 2013Departamento de Engenharia Mecânica e Industrial

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Class 4

The InternetAno 2013

Sistemas de Informaçãopara a Indústria

António GriloProf. Auxiliar FCT-UNL


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The Internet

The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite (often called TCP/IP, although not all protocols use TCP) to serve billions of users worldwide. It is a network of networks that consists of millions of private, public, academic, business, and government networks, of local to global scope, that are linked by a broad array of electronic, wireless and optical networking technologies.

The origins of the Internet reach back to research of the 1960s, commissioned by the United States government in collaboration with private commercial interests to build robust, fault-tolerant, and distributed computer networks. The funding of a new U.S. backbone by the National Science Foundation in the 1980s, as well as private funding for other commercial backbones, led to worldwide participation in the development of new networking technologies, and the merger of many networks. The commercialization of what was by the 1990s an international network resulted in its popularization and incorporation into virtually every aspect of modern human life. As of 2011, more than 2.2 billion people — nearly a third of Earth's population — use the services of the Internet.


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The Internet

Since the mid-1990s the Internet has had a tremendous impact on culture and commerce, including the rise of near instant communication by email, instant messaging, Voice over Internet Protocol (VoIP) "phone calls", two-way interactive video calls, and the World Wide Web with its discussion forums, blogs, social networking, and online shopping sites. Increasing amounts of data are transmitted at higher and higher speeds over fiber optic networks operating at 1-Gbit/s, 10-Gbit/s, or more.

During the late 1990s, it was estimated that traffic on the public Internet grew by 100 % per year, while the mean annual growth in the number of Internet users was thought to be between 20% and 50%. This growth is often attributed to the lack of central administration, which allows organic growth of the network, as well as the non-proprietary open nature of the Internet protocols, which encourages vendor interoperability and prevents any one company from exerting too much control over the network. It is estimated that in 1993 the Internet carried only 1% of the information flowing through two-way telecommunication, by 2000 this figure had grown to 51%, and by 2007 more than 97% of all telecommunicated information was carried over the Internet.


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Internet Services

The Internet has several services available which can be used commerce, entertainment, professional collaboration, professional or personal communication, etc:

· E-mail

· Chatting and instant messaging

· Newsgroups

· Telnet

· File Transfer Protocol (FTP)

· World Wide Web

· Voice over IP (VoIP)

· Unified communications

· Virtual private networks (VPNs)


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Internet Governance

There is no formal management of the Internet Services, nor there is much control over the activities developed over the Internet.

Policies are established by professional, government organizations like IAB, ICANN, W3C. The Internet governance organizations influence government agencies, network owners, ISPs and software developers with the goal of keeping the Internet operating as efficiently as possible. The Internet must also conform to the laws of the nations in which it operates, as well as the technical infrastructures that exist within the nations.

IP addresses currently in use, such as 208.55.112.34 are part of a specification called IP v 5. However, given the growth rate of the Internet, there aren’t enough IP addresses in this scheme to last beyond 2013. IP v 6 is a revised addressing convention that will provide over a quadrillion addresses.


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Internet Client Server Architecture


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The World Wide Web (WWW)

One of the most popular services on the Internet, is the Web and their main protocols enabling the Web. The Web is an interlinked connection of Web sites, which are collections of Web pages linked to a home page. These pages are programmed using HTML, and transmitted to user’s Web browsers by HTTP. Web page addresses (URLs) are composed of the domain name of the web site and the file location of the individual web page

HTML (Hypertext Markup Language) formats documents for display on Web. Hypertext Transfer Protocol (HTTP) is a communications standard used for transferring Web pages. Uniform resource locators (URLs) are addresses of Web pages, e.g., http://www.unidemi.com/sii

Web servers are software for locating and managing Web pages.

The Domain Name System (DNS) is a hierarchical system with a root domain, top-level domains, second-level domains, and host computers at the third level.


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Domain Name System (DNS)


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Voice over Internet Protocol (VoIP)


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Virtual Private Networks (VPN) using the Internet


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Web 2.0


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Future Internet Challenges

- Cloud Computing

- Big Data

- Internet of Things

- Semantic Web / Web 3.0

- Mobile Computing

- Gamification

- …

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