Chapter 5 INTERNET
Objectives of this chapter: You can… Discuss the history of the Internet Explain how to access and connect to the Internet Describe the types of Web sites Imagine the future of the internet
Overview • This chapter covers – – – Introduction History Internet Software Internet Services Future of the Internet
5. 1 Introduction
Introduction • What is the Internet? – – – The largest network of networks in the world Uses TCP/IP protocols and packet switching Runs on any communications substrate
Introduction (cont’d) • • Also called the Net One huge global interconnected networks that comprised millions of computers A world-wide collection of networks that links millions of businesses, government agencies, educational institutions, and individual Internet services widely use – World Wide Web & email
Introduction (cont’d) • A technology to link LAN network to a bigger network • Every computer in the network can directly share data and information with other computers • Internet Service Provider (ISP) are responsible to provide Internet services: – Examples: Jaring, MIMOS, TMNet, Telekom, Maxis. net , Time Telekom
Introduction (cont’d) • “Galactic” Network – – A network that is connected globally where each computers are able to retrieve data directly and share information Every computer on the internet has an IP address (similar to a telephone number) and it is able to exchange data directly with other computers by “dialing” the computer’s address The Internet uses packet switching concept where data sent are divided into smaller units known as packets Each unit of packet has a number and destination address
Introduction (cont’d) • Interoperability – – – The Internet allows every computer in a network to operate even tough each remote computers are of different brands and models or in a cross-platform network. For example, a user can contact other computers like MAC, Windors PC, UNIX Machine and Mainframe using MAC. Telnet is an example of an Internet service where a user can access a remote computer in a network after keying in login and password
Introduction (cont’d) • How to connect to the Internet? Slow-speed technology Dial-up access modem in your computer uses a standard telephone line to connect to the Internet Connection must be established each time you log on. Slow but inexpensive High-speed connection Digital subscriber line (DSL), cable telephone Internet services (CATV), cable modem, fixed wireless, and satellite modems Connection is always on— whenever the computer is running
Introduction (cont’d) – – – All computers have a unique Internet Protocol (IP) address. All computers use TCP/IP protocol to communicate. Requires communication device like modem, ISDN adapter, Ethernet card, telephone line – Download - to transmit data from a remote computer to a local computer Upload - to transmit data from a local computer to a remote computer –
Introduction (cont’d) • TCP/IP – Transmission Control Protocol/Internet Protocol (TCP/IP) – a combined set of protocols that tells computers how to exchange information over the Internet. • TCP monitors and ensures correct transfer of data. • IP receives the data from TCP, breaks it up into packets, and ships it off to a network within the Internet.
Introduction (cont’d) – – Each Internet services require different protocols. Examples like FTP and HTTP sit on top of TCP/IP. • FTP (File Transfer Protocol) – accessed using FTP browser or DOS prompt • HTTP (Hypertext Transfer Protocol) – accessed using Web Browser • POP 3 and SMTP – accessed using Mail Browser
Introduction (cont’d) • Role of ISP – Access is provided by the Internet Service Provider (ISP) i. e. Jaring, TMNet. – ISP provides a back bone to the network – either: • PSTN (Public Switch Telephone Network) • ISDN (Integrated Services Digital Network) or • SONET (Synchronized Optical Network) – ISP also provide domain name registration for each organization.
Introduction (cont’d) • What is a domain name? Ø Text version of Internet protocol (IP) address § Number that uniquely identifies each computer or device connected to Internet
Introduction (cont’d) • Communication Link – Shell Access • Usually by free shell account providers used for textbased email, IRC. • Modem and phone line temporary IP • Computer providers that connect to the Internet (not directly connect to Internet) – Dial-up Point-to-Point (PPP) • Modem, phone line, ISDN adapter temporary IP • Computer Internet
Introduction (cont’d) – Cable/Satellites • Dial-up with modem and phone line temporary IP. • Faster transmission rate. – Leased Line • Modem and dedicated line fixed IP. • Usually to host Internet/Web Server. • Support Extranet (external Internet) i. e. Sony Malaysia and Sony Japan.
How the Internet Works • How might data travel the Internet using a cable modem connection?
5. 2 History
History • 1962 – • Started from Lickder’s “Galactic Network” idea that introduced the concept of Packet Switching. RAND researchers concluded that Packet Switching was the best concept 1968 – • Lawrence G Roberts from DARPA formulated the specifications for Advanced Research Agency Network (ARPANET) 1969 – ARPANET connected 4 computers in California and Utah, connecting university and research center with the Department of Defence (Do. D) - USA
History (cont’d) • 1973 – • ARPANET became an international network 1981 – • ARPANET connected 213 computers 1984 – • Total computers connected to ARPANET reached 1000 1987 – Total computers connected to ARPANET reached 10, 000
History (cont’d) • Packet Switching – In 1962, Galactic Network introduced the concept of packet-switching, a new technology to transfer information between 2 distant computers – Packet-switching technology will break each message/data into smaller unit called packets for speedy and guaranteed delivery – Each packet carries a unique identification number and the destination address
History (cont’d) • ARPANET – (Advanced Research Projects Agency Network) – In 1968, L. G. Roberts from DARPA institute published a specification for Advanced Research Agency Network (ARPANET) – In 1969, ARPANET successfully connected 4 research computers in California & Utah – E-mail services was introduced in 1972 – people exchange text messages across a long distance – In 1973, ARPANET become international network
History (cont’d) – – By 1981, ARPANET has 213 inter-connected computers called the Internet In 1982, ARPANET was taken by DARPA and given to NSF (National Science Foundation) In 1983, the Internet Protocol (TCP/IP) was introduced by Kahn & Cerf By 1984 the network has grown to 1, 000 computers and increased to 10, 000 in the following 3 years
History (cont’d) • World Wide Web (WWW) – In 1989, a researcher named Tim Berners-Lee proposed the idea WWW while working at CERN (a physics laboratory in Europe) – In 1993, a group of professors and students at the University of Illinois National Center for Supercomputing Applications (NCSA) release mosaic – the first graphically based web browser
History (cont’d) • What is the World Wide Web (WWW)? A worldwide collection of electronic documents Also called the Web Each electronic document is called a Web page Can contain text, graphics, sound, video, and built-in connections A Web site is a collection of related Web pages
5. 3 Internet Software
Internet Software • Internet software allows user to use the services provided by the Internet 1. Web Browser – Allows user to view web page and browse Internet sites
Internet Software - www • Example of Web browser Microsoft Internet Explorer Firefox Netscape Opera Mozilla Safari
Internet Software - www • How does a Web browser display a home page? Step 2. Web browser looks up the home page setting Step 3. The Web browser communicates with the ISP’s server to retrieve the IP address. The IP address is sent to your computer. Step 1. Click the Web browser program name Step 4. The home page displays in the Web browser
Internet Software (cont’d) 2. Pager – A software that allows a individual user to communicate with other Internet users. Each user has to have the same software in their computer and register at a certain website for them to obtain an unique identity or ID – The user can then use this software by adding in other user’s ID in his/her pager software to be able to know whether the other user is online on the Internet
Internet Software (cont’d) – – – It is usually used to communicate with other “known” individual; as the user needs to know the other user’s ID Examples of pager software - Yahoo Messenger, ICQ and MSN Messenger etc Some software such as Skype also allows user to communicate via telephone, using Internet as the intermediary medium
Internet Software (cont’d) 3. E-Mail – A software that allows user to read, write and store e -mails – Examples of e-mail software – Microsoft Outlook, Outlook Express, Netscape Messenger and Mozilla Thunderbird 4. Internet Relay Chat (IRC) – A software that allows user to use Internet Relay Chat services (Real-time Chat). – An examples of IRC software – m. IRC
Internet Software (cont’d) 5. Download Manager – Allow users to download files to their computers – It can continue to download the file if the user decide to continue downloading at a later time, or if the user got disconnected and connected again from the network, without having to start the download again from the beginning of the file – However, to continue downloading from where you stop depends on the server that hosts the file(s). Note that not all server support this process – The software is also capable of searching other server that hosts the same file(s), which is faster and/or closer to the user’s location. – E. g. – Flash. Get, Download Accelerator Plus, Godzilla and Real. Network download manager
Internet Software (cont’d) 6. Internet Music Player – Capable of playing music from the internet – Some web pages like radio or tv station’s web sites, provide a web based audio and/or video broadcasting/streaming through the internet. It can only be viewed using special software – Among the popular software Real. Player and Microsoft Media Player – This technology of listening/viewing audio/video through the internet is called “Streaming”
5. 4 Internet Services
Internet Services 1. E-mail – Used to send messages digitally through the internet – Every message delivery should have: address of the recipient, address of the sender, subject of the message and body of the message – Email operations include - reply, forward, delete, save and print – Email will take a few seconds to be sent, it will be stored in the recipient’s email server until the recipient retrieves it. Then the recipient may reply, forward, delete, save or print the email
Internet Services (cont’d) azuramasura@jpa. gov. my • User name/ID: azuramasura • Domain name: jpa • Top-level domain: . gov • Two-letter country extension: . my
Other Internet Services Step 1. Using e-mail software, you create and send message • Step 2. How does an e-mail message travel? Your software contacts software on your ISP’s outgoing mail server Step 4. When recipient uses e-mail software to check for e-mail messages, the message transfers from incoming mail server to recipient’s computer Step 3. Software on outgoing mail server determines best route for data and sends message, which travels along Internet routers to recipient’s incoming mail server
Internet Services (cont’d) 2. File Transfer Protocol (FTP) – FTP is a protocol used to transfer (download or upload) files between computers on the internet. – FTP Client software can be used on PCs to connect to FTP server. – 2 types of modes to transfer files using FTP are: • ACII (text files) • Binary (usually programs, graphics and basically all other file types other than text)
Internet Services (cont’d) – Usually username and password is required to login to FTP service on a FTP server – Anonymous FTP is one way to connect to FTP server without having to identify yourself. Anonymous FTP example: • Type the following command on a DOS prompt ftp. jaring. my Enter the following username an password when asked Login: anonymous or Anonymous Passwd: <enter your email address>
Internet Services (cont’d) 3. Newsgroup/Message boards Ø Newsgroup § Ø Online area where users discuss a particular subject § § Type of discussion group Many Web sites use message boards because they are easier to use Message board
Internet Services (cont’d) 4. Chat – Real-time typed conversation that takes place on a computer – Chat room is location on server that permits users to discuss topics of interest – Instant Messaging – Example: m. IRC, Yahoo Messanger, Skype, MSN Messanger etc
5. Internet Telephony – Real-time audio and video technology, such as Voice Over IP (Vo. IP) and Video Conferencing is getting more popular – Vo. IP techology uses three methods: • PC-to-PC – Using sound card, microphone and computer • Phone-to-PC • Phone-to-Phone – Using Telephones that support Vo. IP – The quality is not guaranteed (No Qo. S), There are noise and echo. All calls are charged as local calls.
Internet Services (cont’d) 6. Telnet – Allows users to login to remote computers using valid username and password. Users need to have an account on the remote computer. Issue the following command in DOS promt telnet www. upm. edu. my – A secured alternative to telnet is by connecting to remote computer using SSH (Secure Shell) ssh www. upm. edu. my – The remote computer must have Telnet/SSH server running for users to connect to it
Internet Services (cont’d) 7. Ping – Allows users to check whether a remote computer is up/operational. Type the following command in DOS prompt ping www. upm. edu. my – This command or service might not work properly if: • • • The server or user is behind a firewall and it blocks ICMP request. Your ISP does not allow this type of request. The server has an embedded firewall on it and it blocks ICMP request.
Internet Services (cont’d) 8. Web Sites – – – – A framework architecture used to share and access documents that is connected to the internet Information displayed are intuitive, easy to use and using interesting graphical interface Information are exchanged using client server concept. A web document that interconnects pages is called hypertext A text string that links a page to other pages is called a hyperlink Hypertext that contains other media (graphics, audio, video, etc. ) is called hypermedia WWW is a world wide hypermedia and hypertext system
Internet Services (cont’d)-website – Every address is unique and is called Universal Resource Locator (URL) http: //www. jaring. my/intro/index. html server protocol – path File name URLs consists of 4 parts: • Protocol: Hyper. Text Transfer Protocol (HTTP) • Server: Internet domain name • Path: The location of the document in the server- folder/directory name • Resources name: The filename, usually in one of these formats html/cgi/sound/movie/graphic
Internet Services (cont’d)-website • Ø What is Search engine Program used to find Web sites and Web pages by entering words or phrases called search text § Also called a keyword
Internet Services (cont’d)-website • What is a hit? Ø Any Web site name that is listed as the result of a search Step 2. Select type of search you want to run Step 1. Go to search engine Step 3. View hits Step 4. Click link to view Web site
Internet Services (cont’d)website • 12 basic types of Web sites Portal News Informational Business/ Marketing Advocacy Blog Wiki Social Network Educational Entertainment Content Aggregator Personal
Internet Services (cont’d)website • Portal Web site Ø A Web site that offers a variety of services from one, convenient location, usually for free § Searching, news, sports and weather, Web publishing, reference tools, stock quotes, maps, shopping, e-mail, and online communities (Web sites that join people with similar interests)
Internet Services (cont’d)-website • News Web site Ø Ø Contains newsworthy material Stories and articles relating to current events, life, money, sports, and the weather
Internet Services (cont’d)-website • Informational Web site Ø Ø Contains factual information Created by organizations and government agencies
Internet Services (cont’d)-website • Business/marketing Web site Ø Ø Contains content that promotes products or services Allows you to purchase products or services online
Internet Services (cont’d)-website • Educational Web site Ø Offers avenues formal and informal teaching and learning § § Some companies offer online training for employees Some colleges offer online classes and degrees
Internet Services (cont’d)-website • Entertainment Web site Ø Offers an interactive and engaging environment featuring music, video, sports, games, and more
Internet Services (cont’d)-website • Advocacy Web site Ø Contains content that describes a cause, opinion, or idea
Internet Services (cont’d)website • Blog web site Ø Ø Ø Short for Weblog Uses a regularly updated journal format to reflect the interests, opinions, and personalities of the author and sometimes site visitors Video blog (vlog), blogosphere, and vlogosphere
Internet Services (cont’d)-website • Wiki web site Ø Collaborative Web site that allows users to add to, modify, or delete the Web site content via their Web browser
Internet Services (cont’d)website • Online social network Ø Ø Ø Encourages members to share their interests, ideas, stories, photos, music, and videos Media sharing Web site Other example? Ø Ø Friendster Facebook Hi 5 Geni (family tree)
Internet Services (cont’d)-website • Content aggregator web site Ø Business that gathers and organizes Web content and then distributes, or feeds, the content to subscribers for free or a fee
Internet Services (cont’d)-website • Personal Web site Ø Ø Web page maintained by private individual Reasons: sharing life experience with the world or job hunting
Internet Services (cont’d)-website • Graphics formats are used on the Web JPEG PNG (pronounced JAY-peg) BMP (pronounced ping) GIF (pronounced JIFF) TIFF
Internet Services (cont’d)-website • What is streaming audio/video? The process of transferring audio/video in a continuous and even flow Enables you to listen to music/ watch video as it downloads to your computer Example of a web site offers video streaming: www. youtube. com Example of a web site offers audio streaming: www. i-bands. net/bandlist. php
Netiquette • What is netiquette? Ø Code of acceptable behaviors users should follow while on the Internet Golden Rule: Treat others as you would like them to treat you.
5. 5 HTML Programming Language
Introduction What is HTML? Ø Hyper. Text Markup Language Ø It provides a means to describe the structure of text-based information in a document—by denoting certain text as links, headings, paragraphs, lists, and so on—and to supplement that text with interactive forms, embedded images, and other objects [wikipedia].
Introduction (cont’d) HTML Version Timeline 1995 1997 HTML 2. 0 HTML 3. 2 1997 2000 HTML 4. 01
Introduction (cont’d) HTML Editor Ø Ø HTML documents are plain-text files that can be created using any text editor Example: Ø Netscape Composer Ø Notepad, word. Web page authoring software Ø Ø Ø Creates sophisticated Web pages without need to type/edit HTML It generates HTML automatically Examples: Ø Ø Ø Dreamweaver Flash Microsoft Frontpage Expression Web Silverlight
Web Page Development How are special effects and interactive elements added to a Web page? Script interpreted program that runs on client Applet usually runs on client, but is compiled Counter tracks number of visitors to Web site Servlet applet that runs on server Image map graphic image that points to URL Active. X control small program that runs on client Processing form collects data from visitors to Web site
Introduction (cont’d) Some scripting language : § § § Java. Script Perl (Practical Extraction and Report Language) PHP (PHP: Hypertext Preprocessor) Rexx (Restructured e. Xtended e. Xecutor) TCL (Tool Command Language) VBScript (Visual Basic, Scripting Edition)
Introduction (cont’d) What are XHTML, XML, and WML? Microbrowser - is a web browser designed for use on a mobile device such as a mobile phone or PDA. XHTML (Extensible HTML) enables Web sites to be displayed more easily on microbrowsers Includes features of HTML and XML Server sends entire record to client, enabling client to do much of processing without going back to server (Extensible Markup Language) allows developers to create customized tags WML (Wireless Markup Language) allows developers to design pages specifically for microbrowsers Many Internet-enabled smart phones and PDAs use WML as their markup language
Web page Development • HTML is composed of tags • Tags - tells browser how to display the information provided • HTML tags are always enclosed in angle-brackets ( < > ) and are case-insensitive • Generally used in pairs – Open tag – Closing tag – same tag with / in front – Example: <tag>. . . </tag>
Web page Development (cont’d) • Basic tags <html> <body> </html> If you view this from the browser, you will see a blank page.
Web page Development (cont’d) • HTML Header and Paragraph <html> <body> <h 1>Heading 1</h 1> <h 2>Heading 2</h 2> <h 3>Heading 3</h 3> <h 4>Heading 4</h 4> <h 5>Heading 5</h 5> <h 6>Heading 6</h 6> <p> This is a paragraph</p> <p> This is another paragraph</p> </body> </html> • See the output of this HTML The text between this tag is displayed as a heading. HTML has six levels of headings, <h 1> through <h 6> with 1 being the largest The text between this tag is displayed as a paragraph
Web page Development (cont’d) • HTML Document – linking – Hyperlink - browser highlights the identified text or image with color and/or underlines to indicate that it is a hypertext link – Relative linking - the path to the linked file relative to the location of the current file. <a href=“page 1. html”> Click Page 1 </a> – Absolute linking - linking to documents that are not directly related <a href=“http: //www. fsktm. upm. edu. my”>FSKTM</a>
Web page Development (cont’d) HTML Links • HTML links are defined with the <a> tag. • Example: <html> <body> <h 3>Universiti Putra Malaysia (UPM)</h 3> <p>UPM is a Malaysia’s leading research intensive public university</p> <a href="http: //www. upm. edu. my">Click here to know more about UPM</a> </body> </html> Target page Clickable text • See the output • Add target=“_blank” to open link in new window – Example: <a href=“www. upm. edu. my” target="_blank">UPM</a>
Web page Development (cont’d) • Create a mailto link – send electronic mail to a specific person or mail alias by including the mailto attribute in a hyperlink – will only work if you have mail installed <html> <body> <p> This is a mail link: <a href="mailto: izuan@fsktm. upm. edu. my">Send Mail</a> </p> </body> –</html>output See
Web page Development (cont’d) • HTML Images – HTML images are defined with the <img> tag. <html> <body> Image source <img src=upmhead. jpg > <h 3>Universiti Putra Malaysia (UPM)</h 3> <p>UPM is a Malaysia’s leading research intensive public university</p> <a href="http: //www. upm. edu. my">Click here to know more about UPM</a> </body> </html> – See the output of this HTML
Web page Development (cont’d) – GIF • • – Graphics Interchange Format Use for graphics JPG • • – Joint Photographic Experts Group Use for photographs PNG • • Portable Network Graphics Expected to replace GIF
Web page Development (cont’d) • An image as a link – This example demonstrates how to use an image as a link. <html> <body> <a href=http: //www. upm. edu. my> <img src=upmhead. jpg> </a> <p>Click on the banner to go to UPM’s portal</p> </body> </html> – See output
Web page Development (cont’d) <p><b>This text is bold</b></p> <p><strong>This text is strong</strong></p> <p><big>This text is big</big></p> <p><em>This text is emphasized</em></p> <p><i>This text is italic</i></p> <p><small>This text is small</small></p> <p>This is<sub> subscript</sub> and <sup>superscript</sup></p> </body> </html> • See output <b> Defines bold text Defines big text <em> Defines emphasized text <i> Defines italic text <small> Defines small text <strong> Defines strong text <sub> Defines subscripted text <sup> Defines superscripted text <ins> Defines inserted text <del> Defines deleted text <s> <html> <body> DESCRIPTION <big> • HTML Text Formatting tag Tag Deprecated. Use <del> instead <strike> Deprecated. Use <del> instead <u> Deprecated. Use styles instead
Web page Development (cont’d) • HTML Style Attribute – The purpose of the style attribute is to provide a common way to style all HTML elements. – HTML Style Examples: • • style="background-color: yellow" style="font-size: 10 px" style="font-family: Times" style="text-align: center“ This is the new style attributes. The obsolete old style was: <body bgcolor=“Powder. Blue”> <html> <body style="background-color: Powder. Blue; "> <h 1>Look! Styles and colors</h 1> <p style="font-family: verdana; color: red">This text is in Verdana and red</p> <p style="font-family: times; color: green">This text is in Times and green</p> <p style="font-size: 30 px">This text is 30 pixels high</p> </body> </html> – See output
Web page Development (cont’d) • Table – Tables are defined with the <table> tag. – divided into rows (with the <tr> tag), and each row is divided into data cells (with the <td> tag). – The letters td stands for "table data" which is the content of a data cell. – A data cell can contain text, images, lists, paragraphs, forms, horizontal rules, tables, etc.
Web page Development (cont’d) • Tables Tags – – <table>. . . </table> - define table in HTML <tr>. . . </tr> - specifies a table row within a table <th>. . . </th> - defines a table header cell <td>. . . </td> - defines a table data cell
Web page Development (cont’d) • Table demonstration – One row and One Column <html> <body> <h 1>one Row One column: </h 1> <table border="1"> <tr> <td><h 1>1, 1</h 1></td> </tr> </table> </body> </html> – See output
Web page Development (cont’d) – One Row Two Column <html> <body> <h 1>One Row and Two Columns</h 1> <table border="1"> <tr> <td><h 1>1, 1</h 1></td> <td><h 1>1, 2</h 1></td> </tr> </table> </body> </html> – See output
Web page Development (cont’d) – Two Row and Two Column <html> <body> <h 1>Two Rows and Two Columns: </h 1> <table border="1"> <tr> <td><h 1>1, 1</td> <td><h 1>1, 2</td> </tr> <td><h 1>2, 1</td> <td><h 1>2, 2</td> </tr> </table> </body> </html> – See output
Web page Development (cont’d) • Tables – more properties – – – BORDER = X - add borders to the table WIDTH=x, HEIGHT=x, - control the size of the table ALIGN=left or center or right - align a table/data to the left, center or right CELLSPACING-the width of the spacing between cell and along edges of cells. CELLPADDING-amount of space inserted btw cell content and the inner edge of a cell
Web page Development (cont’d) • HTML List – HTML supports unordered, ordered and definition lists – Unordered List • marked with bullets (typically small black circles). • starts with the <ul> tag. • each list item starts with the <li> tag – Ordered Lists • marked with numbers. • starts with the <ol> tag • each list item starts with the <li> tag – Definition List • • It is a list of items (terms), with a description of each item (term). starts with a <dl> tag (definition list). each term starts with a <dt> tag (definition term). each description starts with a <dd> tag (definition description).
Web page Development (cont’d) • Demonstration of Unordered list <html> <body> <h 1>An Unordered List: </h 1> <ul> <li><h 1>Coffee</h 1></li> <li><h 1>Tea</h 1></li> <li><h 1>Milk</h 1></li> </ul> </body> </html> • See output
Web page Development (cont’d) • Demonstration of Ordered list <html> <body> <h 1>An ordered List: </h 1> <ol> <li><h 1>Coffee</h 1></li> <li><h 1>Tea</h 1></li> <li><h 1>Milk</h 1></li> </ol> </body> </html> • See output
Web page Development (cont’d) • Demonstration of Definition list <html> <body> <h 1>A Definition List: </h 1> <dl> <dt>Coffee</dt> <dd>Black hot drink</dd> <dt>Milk</dt> <dd>White cold drink</dd> </dl> </body> </html> • See output
End of Chapter 5
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