Internet Rashedul Hasan What is it…… ► Network of the Networks. ► Network of Computers linking many different types of computer all over the world. ► The Internet is a global system of interconnected computer networks that interchange data by using the standardized Internet Protocol (TCP/IP). Networks And Data Communications Visualization of the various routes through a portion of the Internet. History ► The Internet has its root in the ARPANET system of the Advanced Research Project Agency of the U.S department of Defense. ► ARPANET was the first WAN and had only 4 sites in 1969. ► Internet evolved from basic ideas of ARPANET. ► In 1989 the U.S. Govt. lifted restriction on use of the Internet and allowed it to be used for commercial purposes as well. Now…… ► It has interconnects more than 30,000 networks. ► Allowing more than 10 million computers ► More than 50 million users ► In more than 150 countries around the globe to communicate each other. ► It continues to grow up at a rapid pace. The Server Growth of the Internet Source: Internet Software Consortium Users…. ► By region, 40% of the world's Internet users are based in Asia, ► 26% in Europe, ► 17% in North America, ► 10% in Latin America and the Caribbean, 4% in Africa, ► 3% in the Middle East ► and 1% in Australia. Language…. ► The prevalent language for communication on the Internet is English. ► After English (30% of Web visitors) the most requested languages on the World Wide Web are Chinese (17%), ► Spanish (9%), ► Japanese (7%), ► French (5%) ► and German (5%). Governing Bodies… ► Because the Internet is a distributed network comprising many voluntarily interconnected networks, the Internet has no governing body. ► ICANN's role in coordinating the assignment of unique identifiers distinguishes it as perhaps the only central coordinating body on the global Internet, but the scope of its authority extends only to the Internet's systems of domain names, IP addresses, protocol ports and parameter numbers. Governing Bodies… ► The Internet Corporation for Assigned Names and Numbers (ICANN) is the authority that coordinates the assignment of unique identifiers on the Internet, including domain names, Internet Protocol (IP) addresses, and protocol port and parameter numbers ICANN headquarters in Marina Del Rey, California, United States Common uses ► The Internet carries various information resources and services, such as ► electronic mail, ► online chat, ► file transfer and file sharing, ► online gaming, ► and the inter-linked hypertext documents and other resources of the World Wide Web (WWW). ► Social Networking Current Uses of Internet Electronic Mail ► With an Internet email account, users can communicate with anyone else on-line, any place in the world, with no long distance fees. Email can also be used to join mailing lists, bulletin boards, or discussion groups that cover a huge variety of subjects. Current Uses of Internet World Wide Web. ► The World Wide Web is not a physical place, not a set of files, nor even a network of computers. The heart of the WEB lies in the protocols (common communication rules and languages) that define its use. The WWW uses hypertext transfer protocols (http) to transport files from one place to another. World Wide Web. ► "Byusing standardized software, today users can navigate through most features of the Internet, including text data such as email, photo-image files, and video and audio clips.” World Wide Web. ► HTML (HyperTextMarkup Language), the written code that creates Web pages and links, is a language that all computers can read, so computers with varying operating systems (such as Windows and Macintosh) can communicate easily. ► JAVA, a HTML compatible language developed by Sun Microsystems in the mid 1990s, is also universally readable by computers and allows small interactive programs to run on Web pages, creating moving graphic elements such as three- dimensional animations Current Uses of Internet Internet chat, Social networking ► Internet chat and instant messaging systems allow people to stay in touch in a convenient way while working at their computers. Messages can be sent and received instantly. In addition, these systems also allow file transfer, as well as voice and video contact. ► Social networking websites allow people to stay in touch with friends and family, and knowing their activities by viewing their profiles. The concept of a social networking website is to store people’s profiles and connecting them between one and another. A personal profile can include pictures and videos to be shared. Current Uses of Internet VoIP ► VoIP (Voice over Internet Protocol) started from an optional two-way voice chat provided by some of the instant messaging systems that started around the year 2000. The benefit of VoIP is that it can be free or cost much less than a normal telephone call, because the Internet carries that voice traffic. ► VoIP is surely a cheap solution for long distance call. Business Use ► Fastermeans of communication: with the help of E-mail business can stay in touch worldwide with its customer, suppliers and regularities bodies. It can also help in making inexpensive phone call through VoIP and have teleconferencing. Provide product information ► It allows customer direct access to information about company’s products. Some people prefer to learn about products on their own. The Internet has an incomparable ability to make information about a company's products or services available to potential customers. It also provides the information whenever the customer wants it. Save on literature costs ► Providingthe information online reduces the need to print and mail product literature, thereby resulting in significant cost reductions Business Use ► Product Advertising & Promotion: Internet become a very effective but cheap medium of advertisement and promotion. Web sites can be used to provide information on new product, recent strategic alliance, press release and other related information of potential interest to existing and prospective customers. Ex. www.singer.com.bd Online advertising is booming, because… ► Reacha worldwide audience. The Internet is a worldwide network allowing the advertiser to reach people even very expensive advertising could not. ► WWW popularity (graphics, sound, motion). Exciting graphics, sound and even motion can promote and display products, representing a huge advance over the useful but static information available for early email commerce. The Web’s ease of use and instant links to related products and ordering instructions has allowed consumers to respond immediately to online advertising. Online advertising is booming, because… ► Encryption (security for credit and bank card). By the mid 1990s, trustworthy encryption (coding and decoding) technologies made the online use of credit and bank card numbers, addresses, social security numbers and other sensitive information safer for both seller and buyer. (note: safer, not necessarily completely safe). ► Global marketers seek an alternative to television. ► Dozens of start ups want to make a splash in online commerce; their business plans practically force them to buy Internet ads. ► Online world is accommodating advertisers in ways that print and broadcast media would find impossible. Business Use ► Feedback about Product: Business also use the internet to gather information about user satisfaction of existing product, market opportunity of a new product etc. Human Resource Issues: Business can now accept resume/CV through online and can even interview online. Many companies provide current information about job openings and attract talented people from places they could not reach otherwise. www.bdjobs.com www.prothom-alojobs.com Business Use ► Customer Support Service: Many businesses use the internet to provide timely and quick customer services. ► Online Shopping: internet also facilitate the introduction of a new market concept consisting of virtual shops. These shops remain open 24 hours all the year round and make sales happen through internet. [WWW.amazon.com] Let customers try a sample of your product or service ► Many new Web tools are becoming available that will allow consumers to try out a sample of what the company have to offer before they buy. Gain a competitive advantage by offering a "test drive" of your product or service. For example, Test a software applications before you buy them. Internet connection ► Telephone (Dial-up) Modem: Dial up networking technology provides PCs and other network devices access to a LAN or WAN via standard telephone lines. low speed but cheap & widely available. A 6 minute long music video takes 4 hours 45 minutes to be downloaded from WWW with a 28.8 kbps modem. Modem Stands for Modulator and Demodulator. Modulate: Converts digital signals to analog form Demodulate: Converts analog signals back to digital form. Internet connection because telephone lines have traditionally been analog, we need to use modem if our computer is to send signals over a telephone line. The modem converts the computer’s digital signals into telephone line’s analog signals and analog signals back into digital signals. Modem means Modulator demodulator. Modems are rated by their speed in moving data from the computer to the telephone line. This speed is measured in bits per second (bps). Standard modern modems are rated at 28,800 bps, 33,600 bps and 56,400 bps. Networks And Data Communications High Speed phone line ►: ISDN ISDN stands for Integrated Services Digital Network. It is consists of hardware and software that allows data to be transmitted over traditional telephone wire. A 6 minute long music video takes 1 hour to be downloaded from WWW. : DSL Digital Subscriber line. Incoming data are faster then outgoing data. A 6 minute long music video takes 11 minutes to be downloaded from WWW. Cable Modem wireless connection ►A cable modem connects a PC to a cable-TV system that offers an internet connection. ► Wireless system : it includes satellite based radio link connection, Wifi connection etc. ISP: Internet Service Provider: A company that connect you through your communication line to its server, which connect you to the internet via another company’s network access point. Simplified Communications Model - Diagram How the Internet Works How the Internet Works Here's what happens to a piece of data (eg. a Web page) when it is transferred over the Internet: ► It is broken up into a whole lot of same-sized pieces (called packets). ► A header is added to each packet that explains where it came from, where it should end up and how it fits in with the rest of the packets. ► Each packet is sent from computer to computer until it finds its way to its destination. Each computer along the way decides where next to send the packet. This could depend on things like how busy the other computers are when the packet was received. The packets may not all take the same route. How the Internet Works ► At the destination, the packets are examined. If there are any packets missing or damaged, a message is sent asking for those packets to be resent. This continues until all the packets have been received intact. ► The packets are reassembled into their original form. ► Each computer connected up to the Internet has software called TCP/IP (Transmission Control Protocol/Internet Protocol) which is responsible for receiving, sending and checking packets. TCP/IP is the 'glue' of the Internet. E-mail ► www.mail.yahoo.com ► www.gmail.com ► www.hotmail.com email@example.com hasan.rashed = User ID [identifies who is at the address] gmail = domain [a location on the internet] .com = top level domain. .bd = identifies the name of the country. Top level domain Domain Description .biz Business .com Commercial .edu Educational & Research institute .gov Government .info Information .int International Organization Mil Military Organization .net network .org Non-profit & Professional organization E-mail ► ElectronicMail. ► Internet e-mail messages consist of two major sections: ► Header — includes sender, receiver, and other information about the e-mail ► Body — The message itself as unstructured text; sometimes containing a signature block at the end www.mail.yahoo.com www.gmail.com www.hotmail.com Header fields ► The message header usually includes at least the following fields: ► To: The e-mail address [es], and optionally name [s] of the message's recipient [s] ► CC : Carbon copy, for copying message to others. ► Bcc: Blind Carbon Copy, for copying others without the primary recipient knowing it. ► Subject: A brief summary of the contents of the message ► Attachment Large file, music video or MP3 music can be attached and send to the destination address. Spamming ► Spamming is unsolicited commercial e-mail. ► Because of the very low cost of sending e-mail, spammers can send hundreds of millions of e-mail messages each day over an inexpensive Internet connection which may results in information overload for many computer users who receive huge unsolicited email each day Email Spoofing ► Emailspoofing is a kind of forgery. Mails appear to be sent from a known sender but they are actually not so. Spoofing involves forging the email headers, by altering the header information Email Bombing ► Itrefers to transferring a huge amount of emails to victim, ensuing the victim's email account crash. An easy way of attaining this would be to subscribe the victim's email address to a huge number of mailing lists.[ Online chat ► Online chat can refer to direct one-on-one chat or text-based group chat using tools such as instant messengers, Internet Relay Chat, talkers etc. Software ► Windows Live Messenger ► Yahoo! Messenger ► Google Talk ► Internet Relay Chat (IRC) ► ICQ (OSCAR) ► Pal talk WWW & Web Browser ► WWW: World Wide Web. ► Web Browser: is a software that enables users to view web pages and to jump from one page to another. ► Internet Explorer is the mostly widely used web browser. ► Usage share for Q4 2008 ► Internet Explorer: 70.72% ► Firefox: 20.27% ► Safari: 6.77% ► Chrome: 0.78% ► Opera: 0.73% ► Netscape: 0.48% ► Other: 0.24% ► URLs: Uniform Resource Locator. It is the web site’s address. http://www.nps.gov/yose/camping.htm http://= protocol, stands for Hyper Text Transfer Protocol. It is a set of communication rules for exchanging information. It allows brewers to connect with web server. ► www.nps.gov = web server name. it is the particular computer on which this web site is located. ► Yose/ = the directory name. it is the name on the server for the directory or folder from which the browser needs to pull the file. ► Camping.htm = file name. the particular page or document that you are looking for. Web Browser Web Browser Web Browser Web Browser Web Browser Web Browser Web Site, Web page & Web Portals ► Web Site is the location of a web domain name in a computer somewhere on the internet. It is actually a collection of web pages, images, videos or other digital assets that is hosted on one or more web servers, usually accessible via the Internet. On the other hand, ► Web page is document on the WWW that can include text, picture, sound and video. The first page we see at a website is like the title page of a book. This is the Home Page, or welcome page, which identifies the web site and contains links to other pages at the site. ► Web Portals is the website that group together in one convenient location popular features such as search tools, e-mail, and electronic commerce and discussion group etc. portal can be customized to fit user’s interest. The most popular portal are YAHOO, MSN, EXCITE Network etc. Web portal & Search engines ► Web portal: www.yahoo.com ► Web sites that group together in one location. ► Search engine: www.google.com ► It allows us to find specific documents through keyword search. www.yahoo.com web portal. B A W Babel Fish Translations Account Information Weather Bix Address Book Web Hosting Bookmarks Alerts Widgets Buzz Alibaba Wireless Answers Women Z Audio Search C Zimbra Autos Avatars Calendar Chat Company Info Creative Commons Search Y Yahoo! for Good Yahoo! Search Blog Yellow Pages Search engine Movies Pak & Indian MP3 Song www.avg.com www.avast.com www.prothom-alojobs.com www.monster.com www.flickr.com www.youtube.com ► www.facebook.com ► www.hi5.com ► www.myspace.com www.prothom-alo.com www.eprothom-alo.com ► www.cellbaazar.com ► www.wikipedia.com Terminologies ►A network server is a computer designed to process requests and deliver data to other (client) computers over a local network or the Internet. ► Web servers ► proxy servers ► FTP servers ► online game servers Terminologies ► ProxyServers : A proxy server acts an intermediate gateway between you and your Internet connection.
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