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Chapter 7 The Internet, Intranets, and Extranets ITEC 1010 Information and Organizations The Internet The internet A network of networks The internet transmits data from one computer (called a host) to another Internet networks Linked networks that work much the same way -- they pass data around in packets, each of which carries the addresses of its sender and receiver Schematic ITEC 1010 Information and Organizations ITEC 1010 Information and Organizations Internet ‘Discussion’ (1) A global network connecting millions of computers. As of 1999, the Internet has more than 200 million users worldwide, and that number is growing rapidly. More than 100 countries are linked into exchanges of data, news and opinions. Unlike online services, which are centrally controlled, the Internet is decentralized by design. Each Internet computer, called a host, is independent. Its operators can choose which Internet services to use and which local services to make available to the global Internet community. Remarkably, this anarchy by design works exceedingly ITEC 1010 Information and Organizations Internet ‘Discussion’ (2) well. There are a variety of ways to access the Internet. Most online services, such as America Online, offer access to some Internet services. It is also possible to gain access through a commercial Internet Service Provider (ISP). Note: York University’s CCS (Computer and Communications Services) is an ISP. ITEC 1010 Information and Organizations How the Internet Works Transport control protocol (TCP) A protocol that operates at the transport layer and is used in combination with IP by most Internet applications Backbone An Internet high-speed, long distance communications links (like a bus; wire that connects nodes) Uniform resource locator (URL) An assigned address on the Internet for each computer E.g., http://www.yorku.ca/ ITEC 1010 Information and Organizations Domain Affiliations Domain arts com edu firm gov info mil nom net org rec store web net ITEC 1010 Affiliations cultural and entertainment activities business organizations educational sites businesses and firms government sites information service providers military sites individuals networking organizations organizations recreational activities businesses offering goods for purchase entities related to World Wide Web activities networking organizations Information and Organizations Access to the Internet LAN servers • Local servers can provide access to the Internet through normal connections (e.g., Ethernet) Serial line internet protocol (SLIP) and Point-to-point protocol (PPP) • Communications protocol software that transmits packets over telephone lines, allowing dial-up access to the Internet Connection via an on-line service • Examples are America Online and Microsoft Network. These services usually require sign-up procedures ITEC 1010 Information and Organizations Three Ways to Access the Internet Schematic ITEC 1010 Information and Organizations ITEC 1010 Information and Organizations Internet Service Providers Internet service provider (ISP) Any company that provides individuals or companies with access to the Internet Thousands of providers including large communications companies Need an account with the ISP and software that links with TCP/IP ITEC 1010 Information and Organizations ISP Examples Internet Service Provider Web Address AT&T WorldNet Service www.att.com Digex, Inc. www.digex.net GTE Internetworking www.gte.net IBM Internet Connection www.ibm.net MCI Internet www.mci2000.com NetCom On-Line Communication www.netcom.com Services www.psinet.com PSINet, Inc. Sprint Internet Services www.sprint.net Uunet Technologies, Inc. www.us.uu.net ITEC 1010 Information and Organizations Internet Services E-mail Telnet FTP Usenet and newsgroups Chat rooms Internet phone Internet videoconferencing Content streaming ITEC 1010 Information and Organizations Selected Usenet Groups alt.fan.addams.family alt.pets alt.autos.camaro alt.cloning alt.fan.u2 alt.sports.baseball.cinci-red alt.politics.socialism alt.sports.soccer.european.uk ITEC 1010 alt.life.itself alt.fan.bevis-n-butthead alt.fan.leonardo-dicaprio alt.history alt.music.blues alt.music.zz-top alt.sports.college.sec Information and Organizations Internet Services Internet telephony Also called voice-over-IP (VOIP) • Technology that enables network managers to route phone calls and fax transmissions over the same network they use for data ITEC 1010 Information and Organizations ITEC 1010 Information and Organizations VOIP ‘Discussion’ Internet telephony is a category of hardware and software that enables people to use the Internet as the transmission medium for telephone calls. For users who have free, or fixed-price, Internet access, Internet telephony software essentially provides free telephone calls anywhere in the world. To date, however, Internet telephony does not offer the same quality of telephone service as direct telephone connections. There are many Internet telephony applications available. Some, like CoolTalk and NetMeeting, come bundled with popular Web browsers. Others are stand-alone products. Internet telephony products are sometimes called IP telephony, Voice over the Internet (VOI) or Voice over IP (VOIP) products. ITEC 1010 Information and Organizations Content Streaming Content streaming • A method for transferring multimedia files over the • ITEC 1010 Internet so that the data stream of voice and pictures plays continuously, without a break, or very few of them It also enables users to browse large files in real time Information and Organizations The World Wide Web World Wide Web • A collection of tens of thousands of independentlyowned computers that work together as one in an Internet service ITEC 1010 Information and Organizations WWW Terminology Home page • The cover page for a Web site that has graphics, titles, coloured text, etc. Hypermedia • Tools that connect the data on Web pages, allowing users to access topics in whatever order they wish Hypertext markup language (HTML) • The standard page description language for Web pages ITEC 1010 Information and Organizations Some Interesting Web Sites Library of Congress PointCast In-Box Direct Online Career Center New York Times Project Gutenberg Sportsline USA White House MIT Lab for Computer Science The Wall Street Journal ITEC 1010 http://lcweb.loc.gov http://www.pointcast.com http://www.netscape.com http://occ.com http://www.nytimes.com http://www.gutenberg.org http://www.sportsline.com http://www.whitehouse.gov http://www.lcs.mit.edu http://www.wsj.com Information and Organizations WWW Terminology Web browser • Software that creates a unique hypermedia-based menu on your computer screen and provides a graphical interface to the Web Web page • A screen of information sent to a requesting user and presented through a browser Applet • A small program embedded in Web pages ITEC 1010 Information and Organizations HTML “The” language of WWW pages Need we say more!!! ITEC 1010 Information and Organizations Search Engines Search engines A search tool for the Web (like card catalogs in libraries) E.g., Altavista Excite Galaxy Hotbot Infoseek Lycos Webcrawler Yahoo! ITEC 1010 http://www.altavista.digital.com http://www.excite.com http://www.einet.net http://www.hotbot.com http://www.infoseek.com http://www.lycos.com http://www.webcrawler.com http://www.yahoo.com Information and Organizations Java Java An object-oriented programming language Developed by Sun Microsystems Based on C++ Allows small programs -- applets -- to be embedded within an HTML document ITEC 1010 Information and Organizations Applets Applets are small java programs that are downloaded from the server to the local machine ITEC 1010 Information and Organizations Push Technology Push technology • Technology that enables users to automatically receive information over the Internet rather than searching for it using a browser Also called Webcasting • E.g., • PointCast • InterMind ITEC 1010 Information and Organizations Webcasting ‘Discussion’ Using the Internet, and the World Wide Web in particular, to broadcast information. Unlike typical surfing, which relies on a pull method of transferring Web pages, webcasting uses push technologies. ITEC 1010 Information and Organizations Push ‘Discussion’ (1) In client/server applications, to send data to a client without the client requesting it. The World Wide Web is based on a pull technology where the client browser must request a Web page before it is sent. Broadcast media, on the other hand, are push technologies because they send information out regardless of whether anyone is tuned in. Increasingly, companies are using the Internet to deliver information push-style. One of the most successful examples of this is PointCast, which delivers customized news to users' desktops. ITEC 1010 Information and Organizations Push ‘Discussion’ (2) Probably the oldest and most widely used push technology is e-mail. This is a push technology because you receive mail whether you ask for it or not -- that is, the sender pushes the message to the receiver. ITEC 1010 Information and Organizations Business Use of the Web Uses: Applications, E-mail, Product Display, Catalogs, Order placement Products people are likely to buy on the Web Software Books CDs Computer hardware Airline tickets Magazine subscriptions Concert/theater tickets Flowers ITEC 1010 77% 67% 64% 63% 61% 53% 48% 45% Information and Organizations Intranets and Extranets Intranet • An internal corporate network built using Internet and World Wide Web standards and products that allows employees of an organization to gain access to corporate information Extranet • A network based on Web technologies that links selected resources of the intranet of a company with its customers, suppliers, or other business partners ITEC 1010 Information and Organizations Intranet ‘Discussion’ A network based on TCP/IP protocols (an internet) belonging to an organization, usually a corporation, accessible only by the organization's members, employees, or others with authorization. An intranet's Web sites look and act just like any other Web sites, but the firewall surrounding an intranet fends off unauthorized access. Like the Internet itself, intranets are used to share information. Secure intranets are now the fastest-growing segment of the Internet because they are much less expensive to build and manage than private networks based on proprietary protocols. ITEC 1010 Information and Organizations Extranet ‘Discussion’ A new buzzword that refers to an intranet that is partially accessible to authorized outsiders. Whereas an intranet resides behind a firewall and is accessible only to people who are members of the same company or organization, an extranet provides various levels of accessibility to outsiders. You can access an extranet only if you have a valid username and password, and your identity determines which parts of the extranet you can view. Extranets are becoming a very popular means for business partners to exchange information. ITEC 1010 Information and Organizations Virtual Private Network (VPN) Virtual Private Network (VPN) • A secure connection between two points across the Internet Tunneling • The process by which VPNs transfer information by encapsulating traffic in IP packets and sending the packets over the Internet Schematic ITEC 1010 Information and Organizations ITEC 1010 Information and Organizations VPN ‘Discussion’ Short for virtual private network, a network that is constructed by using public wires to connect nodes. For example, there are a number of systems that enable you to create networks using the Internet as the medium for transporting data. These systems use encryption and other security mechanisms to ensure that only authorized users can access the network and that the data cannot be intercepted. ITEC 1010 Information and Organizations Tunneling ‘Discussion’ A technology that enables one network to send its data via another network's connections. Tunneling works by encapsulating a network protocol within packets carried by the second network. For example, Microsoft's PPTP technology enables organizations to use the Internet to transmit data across a virtual private network (VPN). It does this by embedding its own network protocol within the TCP/IP packets carried by the Internet. (Note: PPTP = point-to-point tunneling protocol) Tunneling is also called encapsulation. ITEC 1010 Information and Organizations Internet Issues Management issues No centralized governing body for the Internet Service bottlenecks Phenomenal growth has left a service void Providers underestimating computing power needed Reconciling router addresses needed to transverse the network ITEC 1010 Information and Organizations Privacy & Security Cryptography • The process of converting a message into a secret code and changing the encoded message back to regular text Encryption • The original conversion of a message into a secret code Digital Signature • An encryption technique used for online financial transactions ITEC 1010 Information and Organizations Have a nice day… Encryption software running on sending computer E%$&:”}{|… Decryption software running on Receiving computer ITEC 1010 Information and Organizations Have a nice day… Firewalls Firewalls • A method of preventing unauthorized access between a company’s computers and the Internet (looks at the header of a packet) Assured pipeline • An Internet security method that looks at the entire request for data and then determines whether the request is valid ITEC 1010 Information and Organizations Firewall ‘Discussion’ (1) A system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented in both hardware and software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets. All messages entering or leaving the intranet pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria. ITEC 1010 Information and Organizations Firewall ‘Discussion’ (2) There are several types of firewall techniques: Packet filter: Looks at each packet entering or leaving the network and accepts or rejects it based on user-defined rules. Packet filtering is fairly effective and transparent to users, but it is difficult to configure. In addition, it is susceptible to IP spoofing. Application gateway: Applies security mechanisms to specific applications, such as FTP and Telnet servers. This is very effective, but can impose a performance degradation. Circuit-level gateway: Applies security mechanisms when a TCP or UDP connection is established. Once the connection has been made, packets can flow between the hosts without further checking. Proxy server: Intercepts all messages entering and leaving the network. The proxy server effectively hides the true network addresses. ITEC 1010 Information and Organizations Firewall ‘Discussion’ (3) In practice, many firewalls use two or more of these techniques in concert. A firewall is considered a first line of defense in protecting private information. For greater security, data can be encrypted. ITEC 1010 Information and Organizations End of Chapter 7 Chapter 8 ITEC 1010 Information and Organizations