Chapter NET 2 INTRODUCTION TO THE INTERNET AND WORLD WIDE WEB Before the 90 s the Internet was the domain of the computer industry, universities, and the government. Today there are many people that are introduced to computing through the Internet and the WWW and you can get to the Web from a library, a school, or your choice of a service provider. Companies advertise their sites on TV and use the Internet to market products and take orders. Stores like Victoria s Secret introduce new fashion lines in real time online fashion shows. Car makers let you view models of cars as if you were there looking through a camera. Students and researchers use the Web as a source of information. Lastly, students study about the Web, just like we are going to do today. What is the Internet? Interconnected networks collection of networks Wide Area Network (WAN) Information Superhighway (Iway)? Just what is the Internet? The word Internet stands for Interconnected Networks. It is a collection of networks or a network of networks. Because it is a network that spans a large area, it is a Wide Area Network. It is the start of the Information Superhighway or Iway, the concept of linking all of our homes, businesses, schools, libraries, and government with a high-speed data path capable of carrying all types of multimedia information. Internet Development 1969 - ARPANET - DOD & Universities The 1980s - Internet 1989 - WWW - Tim Berners-Lee 90 s Windows Graphical Interface Commercial Sites Where did the Internet come from? It started in 1969 as an experimental project by the U.S. DOD. They wanted a communications network that wouldn t be crippled if there were outages in parts of the system that were probable if the U.S. were attacked. It was first called ARPANET. The DOD called on universities to help it develop the system. As it developed, more and more schools stated to use it for all types of purposes so colleges and universities were its earliest users. In the 80 s, it was renamed the Internet because it connected networks together. Still it was hard to use and slow. Several things changed this In 1989, Tim Berners-Lee came up with the idea of the World Wide Web. In the 90 s, microcomputers became more powerful with graphics capabilities and networks became faster. Microsoft was able to develop the Windows operating system which had a graphical user interface. Lastly, the Internet was opened to commercial institutions. Today most Web sites are commercial sites. Primary Internet Protocol TCP/IP - Transmission Control Protocol /Internet Protocol Packet Switching 1. Message divided into packets 2. Packets can take different routes to destination 3. Message is reassembled at destination While the Internet uses many protocols, the major or primary protocol of the Internet is TCP/IP which is Transmission Control Protocol / Internet Protocol. TCP/IP uses a method called packet switching. This is how the designers of the Internet achieved the objectives that the DOD wished to accomplish which was to make a network that would still be reliable if parts of the network suffered outages. Chapter NET2 Page 1
1. Packet switching divides a message to be sent into numbered packets. 2. The Internet tries to send each packet by the quickest route to its destination. This might not be the shortest distance route because of outages or because of congestion along some routes. A message s packets may be routed through alternate and different paths. 3. When the packets are received at the destination, they are checked for errors and reassembled into the original message. The Internet Community Today Users Service Providers / Access Providers Content Providers Software and Hardware Companies Governments Internet Society and InterNIC Colleges and Universities The Internet community is very large today. Anyone that has access to computer today can become a part of the Internet community. You and I are probably a part of the users group, people who use Internet services. We get Internet service through service providers or access providers who provide you with a connection. We retrieve information or content that is provided by content providers. We do that using a variety of products form software and hardware companies. Governments make laws that impact the content and behavior of the Internet that you use. The Internet Society and InterNIC guide the workings and development of the Internet and Colleges and universities support Internet research. Myths About the Internet The Internet is Free No, Users pay Someone Controls the Internet No, Guiding organizations, users The Internet and World Wide Web are One and the Same No, WWW is just one use. There are several myths about the Internet but: The Internet is not free. Organizations pay to connect to the Internet. This money goes to support the Internet s structure and for more research. No one controls the Internet. It is guided by organizations such as the Internet Society and by users. Some governments do try to control Internet use and content. The Internet and the WWW are not the same. The WWW is just one use of the Internet. Uses of the Internet E-Mail Information Retrieval and the World Wide Web Gopher Archie Telnet Mailing Lists Newsgroups UseNet Chat Chapter NET2 Page 2
Online Shopping There are many uses of the Internet and we will look at some of these. Electronic Mail One of the first applications to appear on the Internet. The most popular Internet application. E-mail was one of the first Internet applications. It is the most popular Internet application. It is one way that I communicate with you outside of the classroom. We use it to communicate with family, friends, and business associates. When you e-mail someone, you compose a message and then you send it with a mail client program like Eudora. You send it to your mail server who sends it to the recipient s mail server who puts the mail in the recipients mail box. The recipient then uses a client program to retrieve his e-mail from his mail server. One of the protocols that it might use to do this that you might hear of is Post Office Protocol or POP. Information Retrieval: The World Wide Web WWW = Information retrieval system Web Pages = Documents Hyperlinks connect (Hypertext) Links, jumps Web Browser = Client View & navigate Information retrieval is another use of the Internet. The most popular information retrieval application on the Internet is the WWW. On the WWW, The information is organized into documents called Web pages or just pages. Remember, whoever makes this information available is a content provider. These pages are connected by hyperlinks or links which are also called jumps. So this method of document organization is called hypertext. A Web browser is used to view and navigate between pages. A browser is a Web client or desktop client. Information Retrieval: The World Wide Web Web Site Group of pages Home Page Starting page for site Web Surfing Moving between sites Web Server Hosts sites A group of related pages is called a Web site. The first page that you normally visit on a site is the site s home page. When you navigate between Web sites, you are Web surfing or just surfing. The computer system that hosts the site is a Web server. So, the WWW is a client server application running on the Internet. Information Retrieval - Other Gopher Text FTP Chapter NET2 Page 3
File Transfer Protocol... There are other information retrieval methods on the Internet. Gopher is an older text based system that uses menus. FTP or File Transfer Protocol transfers files between you, a client, and a FTP server. You may have used FTP to download a file or some software and not even known it or you may have seen a window with file transfer in progress in it. Microsoft s FTP site is ftp.microsoft.com. There are other information retrieval methods. Mailing Lists Are E-mail discussion groups or Distribution lists Subject-Oriented Moderated Lists Screening A mailing list is either an e-mail discussion group or a distribution list. They are generally subject oriented. For example: student mailing list. If a list is moderated, the messages are screened. Authorized received messages by the list are sent to members of the list. Newsgroups Newsgroups? Like a bulletin board with threads Netiquette (Fig. 2-9, p. 63) Guidelines for newsgroups and e-mail FAQ s DON T SHOUT TOO MUCH OR YOUR MESSAGES WILL NOT BE HEARD! A newsgroup is similar to a bulletin board but the incoming messages are grouped into threads. If you respond to a message or article, you are adding to a thread. Netiquette is an etiquette that you should try to use when participating in a newsgroup or e-mail. Figure 2- on page 63 gives some of these guidelines. For example, you should read a newsgroups FAQ s or Frequently Asked Questions to find out what questions are frequently asked and answered. You shouldn t shout. Shouting refers to the overuse of all caps. Chat and Online Shopping Chat Internet Relay Chat (IRC) & Instant Messenger (IM ) Voice Chat Online Shopping Electronic Malls (E-malls) Intelligent Agents Chat allows you to have a real-time conversation over the Internet. IRC or Internet Relay Chat and Instant Messenger or IM involve sending text messages. Voice chat allows voice conversations although the quality is not great at this point. In the future, they expect voice chat to take part of the telephone market. Internet Addresses To locate something on the Internet requires an address. Part of the address is a domain name which is registered and is unique. It consists of a name and an extension called a root domain. Some common root domain s are shown here. Since most sites are commercial,.com is the most common. Chapter NET2 Page 4
When you specify an address, you sometimes precede the domain with a sub domain, the server prefix. For example, Clemson s mail server is mail.clemson.edu. The Computer Science Dept s Web server is www.cs.clemson.edu. Mailbox Addresses mailbox@domain psterli@clemson.edu psterli@cs.clemson.edu Mailboxes start with the individual s mailbox name followed by an at symbol followed by the server but most of the time the server name is left off and just the server name is specified. WWW Pages: How URLs Work WWW pages use uniform resource locators or URLs. They start with http:// which is assumed by most browsers. HTTP stands for HyperText Transfer Protocol. It is followed by the Web server name which as followed by the request. The request consists of any folders followed by a / and then the document name. If you don t specify a document, most servers assume index.html. The server name is not case sensitive. It doesn t matter how you use upper and lower case. The request may be case sensitive so you should note the capitalization to make sure. It depends on the operating system that is running on the server. A Unix server is case sensitive. A Microsoft Windows server is not. Browsers Mosaic First popular Netscape Navigator Microsoft Internet Explorer To gain access to the Web and many of the Internet services, you need a browser. Mosaic was the first popular browser. Many popular browsers today are based on Mosaic. The most popular browsers today are Netscape Navigator and Microsoft Internet Explorer. Netscape Navigator comes packaged in a suite that also includes: AOL Instant Messenger for chat Collabra for discussion forums Composer for developing Web pages Messenger for e-mail Netcaster for automatic delivery of information Microsoft Internet Explorer comes with Outlook Express for e-mail and newsgroups. Properties of Browsers Functionality Navigation Tools Speed Framing Java and/or ActiveX Support Support for Complex Applications Web-Publishing Capabilities Security If you are picking a broswer package, there are many things to consider although the top two are very similar. Functionally they support applications other than the WWW such as e-mail and FTP. They all use navigation tools like menus and buttons. They also have bookmarks or favorites and history lists. Bookmarks allow you to save the address of frequently accessed sites. History lists keep track of most recently used addresses. Speed is similar. Both use multi-tasking which allows them to do multiple functions in parallel such as downloading while browsing. You can also increase speed by toggling or turning off graphics display so that you only see text. They both support frames. Framing allows the screen to be divided into areas with a different page in each area. Chapter NET2 Page 5
They both support Java and Active-X. There can be thought of as small programs that run as a part of a page that make it interactive. A Java browser program is called an applet. Active-X is a competing technology from Microsoft that is more closely tied to Windows. They both support special complex applications, sometimes through the use of plug-ins. Communicator does have Composer but there are other free Web-publishing programs. Both have good security although Microsoft has had some problems. Plug-in Packages What Are Plug-in Packages? Browser extension software Adobe Acrobat Reader Display & Print PDF files Real Audio/Video MS/Multimedia Player QuickTime The functionality of browsers is extended by plug-ins. One popular plug-in is Adobe Acrobat Reader. It allows you to view PDF documents which are formatted just like a printed page. PDF stands for Portable Document Format. Some audio or video plug-ins use streaming. This allows the browser to buffer part of the file and begin playing it before it is all received. Search Engines What Is a Search Engine? Table of contents or index Examples of Popular Search Engines include: Yahoo, WebCrawler, Lycos, AltaVista, Infoseek, Excite, NeoPlanet, Search for a search string Use AND and OR for boolean (logical) searches There are sites that are search engines. They create a table of contents or an index for what s out there on the Web. Most popular search engines are free. Some search sites use a program called a spider that crawls the Web looking for new pages to index. Some search engines are specialized only cover a specific subject - for example, business. Search engines allow you to put in a search string and then they show you matching sites. Some allow you to use AND and OR to do a boolean or logical search. Netscape is not a search engine but Netscape s home page has a search engine called Netscape Search. Microsoft has a search engine on www.msn.com and AOL has a search engine on www.aol.com called AOL.COM Search Types of Service Providers Commercial Online Services AOL, CompuServe, Prodigy, MSN Internet Service Providers (ISPs) att.net, innova.net SLIP or PPP Other Providers Clemson University To connect to the Internet, you need a service provider. Before the Internet there were commercial online services who had their own private content. The largest commercial online service is AOL who also now owns CompuServe and Netscape. MSN is the Microsoft Network. Don t be confused. MSN is not the same thing as www.msn.com and AOL is not the same thing as www.aol.com. ISP or Internet Service Provider such as AT&T and Innova provide only an Internet connection which generally includes an e-mail address and some disk space for a small Web site. You communicate with your ISP using a type of TCP/IP protocol called SLIP, Serial Line Internet Protocol, or more commonly PPP, Point-to-Point Protocol. Chapter NET2 Page 6
Clemson University is an example of another type of provider. They provide faculty, staff, and students a connection. In The News US News: AOL buying Time Warner. PC Magazine: Instant Messaging. Selecting a Provider Information Provided Cost Speed Service and Support Ease of Use There are several items you should consider when selecting a service provider. One big consideration is whether there is an access number in your calling area. End of Chapter NET 2 Key Terms America Online (AOL). A commercial online service that is a content provider and a service provider. AOL. See America Online. ARPANET. The forerunner to the Internet. Browser. A software tool that makes it easy for users to find and display Web pages. Chat. An Internet feature that supports interactive communications between groups or individuals. Commercial online service. An information service such as AOL or CompuServe that provides proprietary content along with Internet access. Content provider. An organization or individual providing information for distribution over the Internet. Domain name. An order group of symbols, separated by periods, that identifies an Internet server. Electronic mail. The computer-to-computer counterpart to interoffice mail or the postal service. Also called e-mail. E-mail. See Electronic mail. FAQs. See Frequently asked questions. File transfer protocol (FTP). A communications protocol that facilitates the transfer of files between a host computer and a user s computer. Frequently asked questions (FAQs). Typical questions asked by newcomers to Internet newsgroups, mailing lists, and chat rooms, accompanied by the answers to those questions. FTP. See File transfer protocol. Gopher. An information-retrieval tool for the Internet that generates hierarchical, text -intensive menus. Home page. The first page you normally encounter on most Web site visits. Hyperlink. Text or graphic within a WWW page that summons new information. Also called hypermedia. Hypermedia. See Hyperlink. Internet. A global network linking tens of thousands of networks and millions of individual users, businesses, schools, and government agencies. Internet address. A unique identifier assigned to a specific location on the Internet, such as a host computer, Web site, or user mailbox. Internet service provider (ISP). An organization that provides basic access to the Internet. ISP. See Internet service provider. Mailing lists. A service through which discussion groups communicate through shared e-mail messages. Microsoft Internet Explorer. A widely used browser. Microsoft Network. A commercial online service run by Microsoft Corporation. Mosaic. A freeware tool that was the first GUI Web browser to gain wide acceptance; most commercial browsers are enhanced forms of Mosaic. Netiquette. Proper etiquette for exchanges on the Internet. Netscape Navigator. A widely used browsing program. Newsgroup. A service that works like an electronic newspaper, carrying articles posted by subscribers and responses to them (called threads). Search engine. A software tool used to look for specific information over the Internet. Chapter NET2 Page 7
TCP/IP. A collection of communications protocols through which computers accessing the internet can understand each other and exchange data. Stands for Transmission Control Protocol/Internet Protocol. Uniform resource locator (URL). A unique identifier representing the location of a specific Web page on the Internet. URL. See Uniform resource locator. Web server. A computer that stores and distributes Web pages on request. Web site. A collection of related Web pages belonging to an individual or organization. World Wide Web (WWW). A network within the Internet consisting of data organized as pages with hyperlinks to other data. WWW. See World Wide Web. Chapter NET2 Page 8