Chapter 12

Business Data Communications, Fourth Edition Chapter 12: The Internet

Learning Objectives • Explain the history of the Internet • Describe early commands used on the Internet • List and describe the advisory organizations concerned with the Internet • Explain Internet addressing schemes

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Learning Objectives • Describe how the Internet works • Discuss the languages used to create Web pages • Describe Internet services such as search programs, newsgroups, and mailing lists

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Introduction to Chapter • The Internet is widely used by researchers and consumers • “Internet” is a named network, “internet” is the interconnection of networks • The Internet is one of the oldest WANs • The Internet connects homes, schools, businesses worldwide • The history and foundation are important aspects to understanding the makeup of the Internet Chapter 12: The Internet

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History of the Internet • Advanced Research Projects Agency (ARPA) wanted to link remote research sites • Created ARPANET in 1969 • Originally had 4 nodes, used Network Control Protocol (NCP) • Converted to Transmission Control Protocol/Internet Protocol (TCP/IP) in 1983 to allows different OS to communicate • Computer Science Network (CSNet) – Provided connections between universities and industry Chapter 12: The Internet

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History of the Internet • Because It’s Time Network (BITNET) – connected university networks • National Science Foundation Network (NSFnet) – – – –

Funded in 1987 Used to connect supercomputers Backbone network Regional networks took over in 1995

• Commercial Internet eXchange (CIX) – allowed Internet access for commercial users • Internet service providers (ISP) – provide access to the Internet for commercial and private users Chapter 12: The Internet

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History of the Internet • Internet2 (I2) – High-speed network designed to replace the Internet – Useful for hospitals, research, financial institutions – Universities and other research institutions working on it – Abilene is the backbone network for I2

• Next Generation Internet (NGI) – Funded by the US Department of Energy – Closely tied to the development of Internet2

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Early Internet Commands • Telnet – Used to access a remote computer – telnet computer-name – User ID and password required – Can perform any command usually permitted on that computer – Anonymous Telnet • No ID and password required

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Early Internet Commands • File Transfer Protocol (ftp) – Used to transfer a file to a client computer – FTP Client is the program used • Examples: WS_FTP, CuteFTP

– ftp host-computer-name – List of command-line commands used – Anonymous FTP • No ID and password required • Usually need to give your e-mail address

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Early Internet Commands • Gopher – Program that provides a menu for services on an Internet site – Widely used prior to WWW – Gopher server and clients – Can access Gopher sites using a browser

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Early Internet Commands • Archie – Searches indexes of files on public information servers – System of databases

• Veronica – Searches Gopher menus for topics – More sophisticated than Archie – Shows the actual Gopher menu, not just returning the location as is done with Archie Chapter 12: The Internet

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Internet Addressing • IP Addresses – Unique address on the Internet – Also known as a “dotted-quad” • 140.222.32.3

– Internet Information Center (InterNIC) registers the addresses – Classes • • • • •

Class A – Networks with more than 65,536 nodes Class B – Networks with 256 to 65,536 nodes Class C – Networks with fewer than 256 nodes Class D – Broadcast messages Class E – Experimental use

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Internet Addressing • IP Addresses – Classless Internet Domain Routing (CIDR) • Used to extend the number of IP addresses • 186.100.0.0/20 – This one IP address can now cover 4096 additional addresses

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Internet Addessing • Domain Name System (DNS) – Database of Internet names and addresses – Domain names – microsoft.com – Companies buy the names from the InterNIC and then sell them to others – Domain – group of computers with a common set of rules and procedures • Top level domain – .com Chapter 12: The Internet

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Internet Addressing • Domain Name System (DNS) – Internet Ad Hoc Committee (IAHC) has added new top level names • Subdomains – Businesscenter.ibm.com – Nxt2.cso.uiuc.edu

– Domain Name Server – translates name to the IP address

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Internet Addressing • Electronic Mail Addresses – Individual address + domain name address – Mail server – Software is required

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How the Internet Works • Connections to the Internet – ISP connection using a modem – DSL (7Mpbs upload, 640 Kbps download) – Network interface card (NIC) – used when connecting through a corporate or university network – WebTV – Cable Modems – 500 Kbps to 30 Mbps depending on the number of people logged in simultaneously Chapter 12: The Internet

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How the Internet Works • Internet Backbones – Network Service Providers (NSPs) • Operate and maintain backbone networks • Run local and national networks • ISPs connect to the NSPs for their Internet connections

– Network Access Point (NAP) • Interconnection point for NSP backbone networks

– Regional Exchange Points – Metropolitan Area Exchanges (MAEs) • Interconnection point for NSP backbone networks Chapter 12: The Internet

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How the Internet Works • Routers – Provide Internet traffic control – Identify where packets should be sent

• Servers – Computers connected directly to the Internet – Dedicated to serving data on the Internet

• Protocols – TCP/IP used so many different types of computers can communicate – IPv6 will allow more addresses (128-bit addresses) Chapter 12: The Internet

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How the Internet Works • Protocols – Internet Application Protocols • Hypertext Transfer Protocol (HTTP) • Network News Transfer Protocol (NNTP) • Simple Mail Transfer Protocol (SMTP)

– Internet Engineering Task Force (IETF) • Sets new protocols for the Internet

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World Wide Web (WWW) • Graphical user interface to the Internet – Created by Tim Berners-Lee at CERN – Geneva Switzerland, 1991

• Web pages – Hyperlinks – Web site

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World Wide Web (WWW) • Web Programming – Hypertext Markup Language (HTML) – Tags (markups) are special instructions – Can now create them using MS Word and other software packages – Enhanced Hypertext Markup Language (eHTML) – Java – object-oriented programming language – Virtual Reality Modeling Language (VRML) • Duplicate real-life environments Chapter 12: The Internet

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World Wide Web (WWW) • Web Browsers – First browser was Mosaic – Netscape Navigator and Communicator – Microsoft Internet Explorer – Plug-ins • Extends a browser’s capability

– Home pages – Uniform Resource Locator (URL) Chapter 12: The Internet

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World Wide Web (WWW) • Browsers – Hypertext transport protocol (HTTP) – http://www.pnc.edu – Streaming audio and video – RealPlayer – MP3 player

• The Future of the Web – Internet telephony – Faster access through ISDN, DSL, cable modems Chapter 12: The Internet

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Other Internet Services • Search Programs – Search engine is a program to search the web – Some are specialized, some are general

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Other Internet Services • Newsgroups and Mailing Lists (LISTSERVs) – Newsgroups • Articles published by individuals on the Internet • Provides a discussion group service

– Mailing Lists (LISTSERVs) • Must subscribe and unsubscribe • Messages are delivered to you that are sent by other LISTSERV members • Moderated versus unmoderated lists • LISTSERV moderator Chapter 12: The Internet

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Summary • Millions of users access the Internet • History of Internet includes many other networks • Internet Information Center controls Internet addresses • Electronic mail is widely used on the Internet

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Summary • World Wide Web is accessed using one of many browsers • Telnet, FTP, Gopher, Archie and Veronica are text-based programs for accessing Internet • Newsgroups and LISTSERVs are available for exchanging information on the Internet Chapter 12: The Internet

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Chapter 12 Complete