The Internet


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  • The Internet has changed our world. Communications and commerce move instantaneously across borders and around the world. Anyone can publish their wares, their ideas and their desires. Chapter 3 will present a brief introduction into where the Internet came from, how it is structured and describe ways in which the Internet is used.
  • Topics in this chapter include: Internet basics Internet communications Internet multimedia E-Commerce Online annoyances Web browsers URLs Hyperlinks
  • VoIP turns the Internet into a means to place phone calls, including long distance. Uses a protocol similar to e-mail to send voice data. Voice is digitized as an alternative to the analog phone lines. Minimally Requires a microphone an Internet connection A VoIP provider Services differ Free services like Skype require a Skype account on both ends. Paid services like Vonage connect your regular phone to your computer through a special adapter. Cable and DSL providers are offering telephone service through their existing broadband account. WiFi IP phones allow calls through Internet hotspots and wireless networks.
  • Webcasts broadcast audio/visual files but are not updated. Webcasts use streaming media technology to facilitate the viewing and downloading process of large audio and video files. A Wiki is a type of Web site that allows anyone visiting the site to change its content by adding, removing, or editing the content. Wikis provide an excellent source for collaborative writing. Unlike blogs , however, wikis can be edited and therefore maintain a more “common” opinion rather than the direct expressed opinion of the initial individual writer.
  • Newsgroups are sometimes called threaded discussions or discussion groups. Built around topics or interests, participants read entries from other participants and respond, each respondent adding something new to the discussion, creating a thread. A participant can also start a new thread. Unlike chat rooms, threaded discussions don’t rely on instant response but on a more thought-out written response. In distance education classes, threaded discussions are often required, and serve as the class participation component of a course. Listservs are similar except that the threads are sent out as e-mails, where each participant in the thread receives each new posting. They are less public than newsgroups.
  • E-mail has quickly caught on as the primary method of electronic communication because it’s fast and convenient and reduces the costs of postage and long-distance phone calls. Some e-mail accounts are client-based. These programs require a computer with the correct e-mail client. Client-based systems are normally tied to a local ISP and use that domain for an address. If a user changes ISPs, then the e-mail address changes. Web-based e-mail, on the other hand, finds the messages at a host site received by and stored on a mail server, and can be accessed from anywhere. A Web-based e-mail address will stay the same no matter what ISP is used. Free e-mail accounts such as Yahoo! or Hotmail use Web-based e-mail clients.
  • As the Internet has grown, so have the annoying things on it. Some of these are dangerous and some merely annoying. Like heavy traffic on the roads, air pollution, gossip, or any number of annoyances in life, the Internet reflects the public who uses it, with its share of things to add stress to a user’s life. The next few slides will discuss each of these annoyances in more detail.
  • Spam is a particularly difficult problem because there is little that can be done to control the people who send it. All one needs is a list and a message. Lists with millions of e-mail addresses can be purchased. There have been laws passed to make sending spam illegal, but they are difficult to enforce. One way to avoid spam in your primary account is to create a special e-mail address that you use when you fill out forms on the Web. A spam filter is an option you can select in your e-mail account that places known spam messages into a folder other than your inbox . 95% of spam can be filtered, never reaching your inbox. You should are careful by reading privacy practices carefully before registering your name on Web sites, by not replying to spam, and reporting spam to agencies that filter and fight spam.
  • Pop-up windows are the billboards of the Internet. Some sites use pop-ups to increase the functionality of their site (your account balance may pop up at your bank’s Web site, for example). There are ways to reduce or eliminate pop-ups. Firefox and Safari have built-in pop-up blockers. Windows includes a Pop-up Manager to Internet Explorer that allows you to selectively block pop-ups. If you feel you need more protection, you can install anti-pop-up software such as Pop-Up Stopper and Pop-Up Defender.
  • Cookies are a necessary annoyance because they enhance the Web experience and speed up Web page loading. When you go to a Web page for the first time, the Web document drops a small text file in a folder. This text file saves information about the user and assigns an identification code so that when the user returns, the same preferences are loaded and the Web site may be more geared to the user. This is critical on sites where the content is somewhat chosen to meet the user’s wishes, like in My Yahoo or other personalized sites. Although cookies are generally not privacy risks, there have been cases in which the information has been collected and sold to advertisers.
  • Often a company will offer something for free, like a screensaver or a game. Piggybacked with the program is a hidden spyware program that monitors your browsing and sends this information back to a server. Spyware removal software is available from many sources, often for free, and can effectively find and destroy these annoyances.
  • If you receive an official looking e-mail from your bank saying that there has been a software security breach and to help regain control you need to confirm your username and password, don’t do it. This is one of the most common scams called phishing. The e-mail is made to look very official, with logos and signatures, and many unsuspecting customers have entered their passwords into the return. Hoaxes often are offers to make millions from a distraught African ex-prince or to help the victims of a hurricane. It is always best to absolutely know who is sending the message before responding.
  • Software that has a malicious intent is called malware . Spyware is a form of malware. Other forms of malware are viruses, worms, and Trojan horses. Malware is designed to render a computer useless or penetrate it completely.
  • The three-letter suffix in the domain name (such as .com or .edu) is called the top-level domain (TLD) . This suffix indicates the kind of organization the host is. The most used is the .com or commercial domain, which can be used by anyone. There are also domains for countries outside the United States. For instance a Web site in Germany has the extension .de and in Britain it is .uk. The three-letter suffix in the domain name (such as .com or .edu) is called the top-level domain (TLD) . This suffix indicates the kind of organization the host is. The most used is the .com or commercial domain, which can be used by anyone. There are also domains for countries outside the United States. For instance a Web site in Germany has the extension .de and in Britain it is .uk.
  • A URL is a Web site’s address. It is composed of several parts that help identify the Web document for which it stands. The first part of the URL indicates the set of rules (or the protocol ) used to retrieve the specified document. HTTP is most common. Another popular protocol is FTP. The protocol is generally followed by a colon, two forward slashes, www (indicating World Wide Web), and then the domain name . Domain names consist of two parts: the host and the top-level domain (TLD) . At times, a forward slash and additional text follow the domain name . The information after the slash indicates a particular file or path (or subdirectory ) within the Web site.
  • Web browser is software installed on your computer system that allows you to locate, view, and navigate the Web. Web browsers are graphical, meaning they can display pictures (graphics) in addition to text, as well as other forms of multimedia, such as sound and video. Although Microsoft Internet Explorer is the most used web browser, there are other browsers available. All of them have similar tools. Because Microsoft products are the main targets for virus writers, an alternative browser may be less vulnerable. Camino is a new browser developed by Mozilla for the Mac OS X platform.
  • The first page in a Web site is called the home page. If you type the domain name into the browser window, the server will find the site and look for a file called index.htm, the standard name for the home page. Every web page has a unique URL and is an HTML document. It may or may not have links to other pages or other Web sites.
  • A search engine is a set of programs that searches the Web for specific keywords you wish to query and then returns a list of the Web sites on which those keywords are found. Search engines have three parts. The first part is a program called a spider , which collects data on the Web. An indexer program organizes the data into a large database. The search engine software searches the indexed data, pulling out relevant information according to your search. Using search engines like Google, users can scan millions of Web sites in seconds, with the search page returning thousands of relevant Web pages. Revenue is generated by offering a side column of paid links that are ties to certain search requests. For instance, if you put “cat food” in the search box, Google returns many related sites. Businesses who agreed to pay to have their link appear when someone requests “cat food” pay a small amount for every time their ad links appears.
  • Evaluating the content of a web site is important. Before you believe what the site says or take action based on the information presented, several questions need to be answered. Who exactly owns and operates the Web site? Who are they trying to reach with their message? Are the opinions expressed objective, or are they slanted toward one position or another? If it is slanted, why is it slanted? Is the information up to date? How often is the site updated? Do the hyperlinks all work or are some dead-ends? Like anything else, how well maintained a site is helps determine its believability.
  • The basic information about the Internet includes its origin, how the Web relates to the Internet, how the Internet is based on clients and servers, and how to best connect to the Internet.
  • The Internet is a huge client/server network. Thus, a computer connected to the Internet acts in one of two ways: it is either a client , a computer that asks for data, or a server , a computer that receives the request and returns the data to the client.
  • To take advantage of the resources the Internet offers, you need a means to connect your computer to it. Home users have several connection options available. The most common is a dial-up connection . A dial-up connection is the least costly method of connecting to the Internet, needing only a standard phone line and a modem. A modem is a device that converts ( mod ulates) the digital signals the computer understands to the analog signals that can travel over phone lines. In turn, the computer on the other end must also have a modem to translate ( dem odulate) the received analog signal back to a digital signal for the receiving computer to understand. Modern desktop computers generally come with internal modems. Laptops use either internal modems or PC cards that are inserted into a special slot on the laptop. Current modems have a maximum data transfer rate of 56 Kbps, usually referred to as 56K.
  • Other connection options, called broadband connections , offer faster means to connect to the Internet. Broadband connections include DSL, cable, and satellite. DSL uses a standard phone line to connect to the Internet . However, the line is split between digital and voice, meaning that the digital signal does not have to be converted into sounds, and greater speeds can be realized. DSL requires a special DSL modem. Although the monthly fee is higher than dial-up, there is no need for a second phone line, and often the end price is comparable, but the Internet speed is at least double. Not all areas of the United States have DSL. Also, in order to use DSL, your telephone connection must be within fairly close proximity of a switching station. DSL provider Web sites include interactive tools you can use to determine whether your phone line is capable of including a DSL connection. The more typical DSL transmissions download data from the Internet faster than they can upload data. Such transmissions are referred to as Asymmetrical Digital Subscriber Line (ADSL) . Other DSL transmissions, called Symmetrical Digital Subscriber Line (SDSL) , upload and download data at the same speed.
  • Another broadband connection is cable Internet. Cable Internet uses coaxial cable and a cable modem. If your cable company has an Internet service, you can receive data at speeds up to 4 Mbps and send data at approximately 500 Kbps. As technology improves, these transfer rates also will improve. This always-on connection can be slowed by the number of users connected at any one time, and it is not available in all areas.
  • Satellite Internet is another broadband option. You need a satellite dish, which is placed outside your home and connects to your computer with coaxial cable. Therefore, the initial equipment investment is high. Most satellite connections are used by people in rural areas unable to get cable or DSL connections. Even though bandwidth can be high, the signal must travel a long distance from the satellite and back, increasing the delay time. In North America, the southern sky has to be free of obstruction, and heavy rain can cause interference in the signal.
  • Internet connection costs vary widely as does the performance. Generally, dial-up will cost from $10 to $25 per month for an unlimited connection. DSL is being offered for $25 to $40 per month for ADSL. Cable costs about $40 per month if it is coupled with cable television service. Satellite costs between $50 and $90 per month. A thorough investigation is recommended for anyone deciding to obtain Internet access.
  • The choice of Internet Service Provider should be based on cost versus service. It is very important that a dial-up provider offer a local access number, so that there are no long distance charges incurred. Many providers will offer multiple e-mail accounts and some will provide space for a personal Web page. Local ISPs sometimes maintain sites with local information and Web links.
  • The Internet was created to respond to two concerns: to establish a safe form of military communications and to create a means by which all computers could communicate. Scientists were asked to come up with a solution to secure communications between large computer centers in case of a nuclear attack. They responded by inventing packet-switching and routers. By taking data messages and breaking them into small packets, each packet could be addressed and sent individually to a destination through a series of routers. The routers, like robot traffic cops, would send each packet along the optimum path to the next router, depending on traffic and availability. This development also gave birth to a network that could be scaled up infinitely. It could be argued that the scientists who quietly built the first packet-switched network in 1969 were more important to the future than the NASA scientists who landed a man on the moon in the same year.
  • What distinguishes the Web from the rest of the Internet is its use of: Common communication protocols (such as TCP/IP) and special languages (such as the Hypertext Markup Language, or HTML). Special links (called hyperlinks ) enabling users to jump from one place to another on the Web The Web was invented long after the Internet, in 1989 by Tim Berners-Lee at CERN in Switzerland. In 1993, the National Center for Supercomputing Applications (NCSA) released the Mosaic browser. Many of the developers from the original Mosaic project at the NCSA worked for a new company, which released the Netscape browser (Netscape Navigator 1.0) in December 1994. Netscape heralded the beginning of the Web’s monumental growth.
  • Internet development in the early 1990s gave birth to the Web. One crucial development was the introduction of Hypertext Markup Language (HTML) and Hypertext Transfer Protocol (HTTP): the software technologies that allow Web pages to link to other Web pages, whether they are on the same server or on the other side of the world. The other critical development was the browser, multiplatform software that allows users to see HTML files, called Web pages. Thus, the Web is a subset of the Internet, but because of its tremendous use, it represents the largest amount of Internet traffic.
  • The Internet will continue to have great influence in the future. Greater bandwidth, wireless access and the amalgamation of telephone, TV, and Internet technologies will bring change and spur new, unforeseen developments. The U.S. government sponsors research called the Large Scale Networking (LSN) program, which funds cutting-edge research in wireless and networking technologies. Another major effort is Internet2, a cooperative research project of over 200 universities. A major thrust of their research is increased bandwidth for the whole Internet. There are also companies working on smell generators and printers that output taste cards. We are still in the beginning stages of Internet development. As the technology becomes more and more part of the fabric of our lives, newer and better methods for using these tools will emerge. What it all becomes will be determined by users. Each of us who uses the Internet will help shape it in the future.
  • The Internet

    1. 1. <ul><li>Using the Internet: </li></ul><ul><li>Making the Most of the Web’s Resources </li></ul>
    2. 2. Topics <ul><li>Internet communications </li></ul><ul><li>Online annoyances </li></ul><ul><li>How the Internet works </li></ul><ul><li>Internet Basics </li></ul><ul><li>Origin of the Internet </li></ul><ul><li>Future of the Internet </li></ul>
    3. 3. Communications through the Net <ul><li>VOIP </li></ul><ul><li>Wikis </li></ul><ul><li>Newsgroups </li></ul><ul><li>Email </li></ul><ul><li>Mailing lists </li></ul><ul><li>Social networking </li></ul><ul><li>E-commerce </li></ul>
    4. 4. Voice over Internet Protocol <ul><li>VoIP - The Internet as a means to place phone calls </li></ul><ul><li>Uses technology similar to e-mail to send voice data digitally </li></ul><ul><li>Requires </li></ul><ul><ul><li>a microphone </li></ul></ul><ul><ul><li>an Internet connection </li></ul></ul><ul><ul><li>A VoIP provider </li></ul></ul><ul><li>Services differ </li></ul><ul><ul><li>Free services require an account on both ends </li></ul></ul><ul><ul><li>Paid services connect phone to computer </li></ul></ul><ul><ul><li>Cable and DSL providers offer phone through broadband </li></ul></ul><ul><ul><li>WiFi IP phones call through Internet hotspots and wireless networks </li></ul></ul>
    5. 5. Wikis <ul><li>A wiki is a Web site that allows anyone to change its content </li></ul><ul><li>Wikis provide an excellent source for collaborative writing </li></ul><ul><li>Unlike blogs, wikis can be edited for a “common” opinion </li></ul><ul><li>Edits can be anonymous or named </li></ul><ul><li>Be careful of bias in entries </li></ul><ul><li>“ wiki” is a Hawaiian word for “fast” </li></ul><ul><li>First site with wiki in the name set up in 1995 </li></ul>
    6. 6. Newsgroups <ul><li>Usenet &quot;News&quot; formed in 1980 </li></ul><ul><li>Online discussion forums </li></ul><ul><li>Post and reply to messages publicly </li></ul><ul><li>Need a feed from a news server - most ISPs have one </li></ul>
    7. 7. E-mail <ul><li>fast, convenient, cheap </li></ul><ul><li>asynchronous </li></ul><ul><li>E-mail accounts </li></ul><ul><ul><li>Client-based </li></ul></ul><ul><ul><li>Web-based </li></ul></ul><ul><li>Forwarding </li></ul><ul><li>(image from Wikipedia &quot;How Email Works&quot;) </li></ul>
    8. 8. Mailing lists <ul><li>&quot;Listservs&quot; </li></ul><ul><li>people must subscribe </li></ul><ul><li>messages sent by email </li></ul><ul><li>sent only to people who subscribe, not general public </li></ul><ul><li>do NOT use the &quot;Reply All&quot; option unless you mean to! </li></ul>
    9. 9. Social Networking <ul><li>MySpace, FaceBook </li></ul><ul><li>easy, cheap </li></ul><ul><li>danger of identity theft </li></ul><ul><li>danger of revealing information which can be harmful later </li></ul><ul><li>danger of sexual predators </li></ul>
    10. 10. E-commerce <ul><li>buying, selling, advertising, banking </li></ul><ul><li>look for secure &quot;signed&quot; sites </li></ul><ul><li>https:// versus http:// </li></ul><ul><li>check with Better Business before buying </li></ul><ul><li>use credit card for purchase </li></ul>
    11. 11. Online Annoyances <ul><li>Spam – electronic junk mail </li></ul><ul><li>Pop-ups – intrusive advertising </li></ul><ul><li>Cookies – tracking user’s browsing habits </li></ul><ul><li>Malware - software that has a malicious intent - spyware, viruses, Trojans, worms, etc. </li></ul><ul><li>Phishing and Hoaxes – Ruses to fool and maybe steal from users </li></ul>
    12. 12. Spam <ul><li>Junk e-Mail </li></ul><ul><li>May soon comprise 90% </li></ul><ul><li> of email volume </li></ul><ul><li>Named after a Monty Python sketch Link </li></ul><ul><li>Antispam practices </li></ul><ul><ul><li>Don’t reply to it, even to “unsubscribe”! </li></ul></ul><ul><ul><li>Use “dummy” addresses – can get free ones </li></ul></ul><ul><ul><li>Read privacy statement on a site before you give them your address </li></ul></ul><ul><ul><li>Spam filters </li></ul></ul>
    13. 13. Pop-ups <ul><li>Usually advertising </li></ul><ul><li>Pop-up automatically </li></ul><ul><li>Can also contain spyware </li></ul><ul><li>Most browsers can prevent them </li></ul><ul><li>Pop-up blockers </li></ul>
    14. 14. Cookies <ul><li>Text files stored on client computers when visiting Web sites </li></ul><ul><li>Used on return visits to Web sites </li></ul><ul><li>Unique ID number </li></ul><ul><li>Personal information remembered </li></ul><ul><li>Privacy risk </li></ul><ul><ul><li>Selling information </li></ul></ul>
    15. 15. Spyware <ul><li>Added as a program piggybacked with a requested program </li></ul><ul><li>Secretly gathers information, usually about surfing habits </li></ul><ul><li>Antivirus software doesn’t detect it </li></ul><ul><li>Spyware removal programs are required </li></ul>
    16. 16. Spyware <ul><li>Very often comes in from file-sharing, P2P sites </li></ul><ul><li>Ties up system resources, can modify browser settings, can spawn popups and other ads </li></ul><ul><li>Read the EULA for any software you install before you install! </li></ul><ul><li>Run Ad-Aware to clean it up </li></ul>
    17. 17. Phishing and Hoaxes <ul><li>Phishing is a phony communication from a trusted source </li></ul><ul><li>Phishing attempts to scam someone into sending vital information </li></ul><ul><li>Hoaxes are attempts to scam people into sending money, or join a chain letter </li></ul>
    18. 18. Malware <ul><li>Software that has a malicious intent </li></ul><ul><li>Spyware is a form of malware </li></ul><ul><li>Other forms are viruses, worms, and Trojan horses </li></ul><ul><li>Designed to render a computer useless or control it completely </li></ul>
    19. 19. How the Internet works <ul><li>Domain Names </li></ul><ul><li>URLs </li></ul><ul><li>Navigating the Web </li></ul>
    20. 20. Domain Names <ul><li>Easy-to-remember names for Internet servers </li></ul><ul><ul><li>Ends with an extension that indicates its top-level domain </li></ul></ul><ul><li>Every domain name corresponds to a unique IP address </li></ul><ul><ul><li>Domain Name System </li></ul></ul><ul><ul><li>cybersquatting </li></ul></ul><ul><li>ICANN coordinates technical management of the Internet’s Domain Name System </li></ul>
    21. 21. Domain Names <ul><li>Most specific information on the LEFT </li></ul><ul><li>Top Level Domain Names </li></ul><ul><ul><li>.gov .com .edu .net </li></ul></ul><ul><li>Subnets and Sub Domains </li></ul><ul><ul><li> </li></ul></ul><ul><ul><li> </li></ul></ul><ul><ul><li> </li></ul></ul><ul><ul><li> </li></ul></ul>
    22. 22. Current Top-Level Domains <ul><li>. aero Members of the air transport industry </li></ul><ul><li>.biz Businesses </li></ul><ul><li>.com Can be used by anyone </li></ul><ul><li>.coop Cooperative associations </li></ul><ul><li>.edu Degree granting institutions </li></ul><ul><li>.gov United States government </li></ul><ul><li>.info Information service providers </li></ul><ul><li>.mil United States military </li></ul><ul><li>. museum Museums </li></ul><ul><li>. name Individuals </li></ul><ul><li>.net Networking organizations </li></ul><ul><li>.org Organizations (often nonprofits) </li></ul><ul><li>.pro Credentialed professionals </li></ul>
    23. 23. Top Level Domains - Country Codes
    24. 24. URL <ul><li>Uniform Resource Locator </li></ul><ul><ul><li>Unique Internet address </li></ul></ul><ul><ul><ul><li>Protocol could be http, mailto, ftp, news, … </li></ul></ul></ul><ul><ul><ul><li>NOTE difference between http and https </li></ul></ul></ul>URL http:// Protocol identifies the means of access Domain name contains the host and top-level domain Pages/cartoons/ Path identifies the subdirectories within the Web site
    25. 25. Navigating the Web: Web Browsers <ul><li>Software running locally on your machine </li></ul><ul><li>Graphical </li></ul><ul><li>Enables Web navigation </li></ul><ul><li>Popular browsers: </li></ul><ul><ul><li>Internet Explorer </li></ul></ul><ul><ul><li>Firefox </li></ul></ul><ul><ul><li>Camino (Mac OSX) </li></ul></ul>
    26. 26. Web Sites <ul><li>Web site: </li></ul><ul><ul><li>Collection of related Web pages </li></ul></ul><ul><ul><li>First page known as Home or Index page </li></ul></ul><ul><li>Web pages: </li></ul><ul><ul><li>HTML documents </li></ul></ul><ul><ul><li>Hyperlinks </li></ul></ul>Related pages
    27. 27. The Internet and Copyright <ul><li>All original material on the Net is copyrighted, © or not </li></ul><ul><li>Copyright is violated when you get economic benefit from using the material </li></ul><ul><ul><li>Exception of &quot;academic fair use&quot; </li></ul></ul><ul><li>Plagiarism is different from copyright violation – it is presenting someone else's work as your own </li></ul><ul><ul><li>Credit your sources! </li></ul></ul>
    28. 28. Search Engines <ul><li>“ Spider” or “Web Crawler” program scans Web pages </li></ul><ul><li>Information found is entered in their database </li></ul><ul><li>User enters keyword or phrase in search box in browser </li></ul><ul><li>Results (hits) are sent to the client software and displayed </li></ul>
    29. 29. Evaluating Web Sites <ul><li>Who is the author of the article or Web site sponsor? </li></ul><ul><li>What audience is the site geared toward? </li></ul><ul><li>Is the site biased? </li></ul><ul><li>Is the information current? </li></ul><ul><li>Are links available? </li></ul><ul><li>Who is hosting? Is it a .gov site? .edu? .com? </li></ul>
    30. 30. File-sharing - P2P networks <ul><li>Files traded from machine to machine - broadband </li></ul><ul><li>Majority of files are copyrighted and permission has not been given for the copying </li></ul><ul><li>Risks </li></ul><ul><ul><li>Legal problems </li></ul></ul><ul><ul><li>Malware in both the software and the files </li></ul></ul>
    31. 31. Software Copyrights and Licenses <ul><li>Different types of software licenses - where the money come from? </li></ul><ul><ul><li>Commercial software -from sale of licenses </li></ul></ul><ul><ul><li>Shareware - from registrations and ads </li></ul></ul><ul><ul><li>Freeware - from advertising and spyware </li></ul></ul><ul><ul><li>Open source - free labor of volunteers and donations </li></ul></ul><ul><ul><li>Public domain - donations from community </li></ul></ul>
    32. 32. The Internet: The Basics <ul><li>Protocols </li></ul><ul><li>IP numbers </li></ul><ul><li>Clients and servers </li></ul><ul><li>Connecting to the Internet </li></ul><ul><li>Origin of the Internet </li></ul><ul><li>The Internet vs. the Web </li></ul>
    33. 33. Internet Protocols <ul><li>TCP and IP serve as the primary protocols responsible for message transmission on the Internet </li></ul>
    34. 34. Internet Protocol <ul><li>Messages are divided into small pieces called packets </li></ul><ul><li>These are labeled with the IP numbers of the machine they came from and the one they are going to, and a order number ( like 1 of 5) </li></ul><ul><li>The protocol says how to route them to get to the destination </li></ul><ul><li>Not all packets take the same route! </li></ul>
    35. 35. IP Addresses <ul><li>IP addresses are addresses that identify computers on the Internet </li></ul><ul><ul><li>Static IP address </li></ul></ul><ul><ul><li>Dynamic IP address </li></ul></ul>
    36. 36. IP Addresses <ul><li>IP addresses have the problem in TCP/IP of running out </li></ul><ul><li>Internet 2 consortium designing new protocols that fix the problem </li></ul><ul><li>Dynamic IP numbers – short term fix </li></ul>
    37. 37. Client and Server <ul><li>Client computer: </li></ul><ul><ul><li>Users connect to the Internet </li></ul></ul><ul><ul><li>Request data and Web pages </li></ul></ul><ul><li>Server computers: </li></ul><ul><ul><li>Store Web pages and data </li></ul></ul><ul><ul><li>Return the requested data to the client </li></ul></ul>Server Client
    38. 38. Connecting to the Internet <ul><li>Dial-up connection: </li></ul><ul><ul><li>Uses standard telephone line </li></ul></ul><ul><ul><li>Least costly connection </li></ul></ul><ul><ul><li>Requires a modem </li></ul></ul><ul><ul><ul><li>Converts analog to digital and vice versa </li></ul></ul></ul><ul><ul><li>Slowest connection speed (56Kbps) </li></ul></ul>
    39. 39. Broadband Connections <ul><li>Digital Subscriber Lines </li></ul><ul><ul><li>Faster than dial-up </li></ul></ul><ul><ul><ul><li>Upload (300Kbps – 1.5Mbps) </li></ul></ul></ul><ul><ul><ul><li>Download (1Mbps – 1.5Mbps) </li></ul></ul></ul><ul><ul><li>Requires special DSL modem </li></ul></ul><ul><ul><li>Symmetrical or Asymmetrical </li></ul></ul>DSL modem
    40. 40. Broadband Connections <ul><li>Cable: </li></ul><ul><ul><li>Uses TV coaxial cable </li></ul></ul><ul><ul><li>Fast connection speed (500Kbps – 4Mbps) </li></ul></ul><ul><ul><li>Speed depends on number of users </li></ul></ul><ul><ul><li>Not available in all areas </li></ul></ul><ul><ul><li>Requires a cable modem </li></ul></ul>Coaxial cable
    41. 41. Satellite Connections <ul><li>Uses a satellite dish and coaxial cable </li></ul><ul><ul><li>Download speed 500 kbps </li></ul></ul><ul><ul><li>Upload speed 100 kbps </li></ul></ul><ul><ul><li>Signal is affected by location and weather </li></ul></ul>
    42. 42. Comparing Internet Connection Options 500 Kbps 100 Kbps Satellite 4 Mbps 500 Kbps Cable 1.5 Mbps 1.5 Mbps DSL (SDSL) 1 Mbps 300 Kbps DSL (ADSL) 56 Kbps 56 Kbps Dial-Up Maximum Download Data Transfer Rate (approximate) Maximum Upload Data Transfer Rate (approximate) Connection Option
    43. 43. Choosing an ISP <ul><li>Factors to consider: </li></ul><ul><ul><li>Cost </li></ul></ul><ul><ul><li>Local access numbers </li></ul></ul><ul><ul><li>Services Offered – email, web page hosting, news reading </li></ul></ul><ul><ul><li>Reliability </li></ul></ul><ul><ul><li>Speed </li></ul></ul><ul><ul><li>Support and Customer Service </li></ul></ul>
    44. 44. ISP Infrastructure
    45. 45. The Origin of the Internet <ul><li>ARPANET: </li></ul><ul><ul><li>Advanced Research Projects Agency Network </li></ul></ul><ul><ul><li>Funded by the U.S. government in the 1960s, lasts until 90's </li></ul></ul><ul><ul><li>Allowed computers at leading universities and research organizations to communicate with each other over great distances </li></ul></ul><ul><ul><li>First Working Version of the Packet Switching Network </li></ul></ul>
    46. 47. NSFNet – National Science Foundation Network <ul><li>Connecting 5 supercomputers and the researchers using them, 1986 </li></ul><ul><li>commercialization of the Internet - late 80's </li></ul><ul><li>NSF stops funding the Net - 1994 </li></ul>
    47. 48. Internet Structure
    48. 49. The Web <ul><li>The Web is a part of the Internet distinguished by: </li></ul><ul><ul><li>common communication protocols TCP/IP and HTML </li></ul></ul><ul><ul><li>special links (called hyperlinks ) </li></ul></ul><ul><li>Web invented in 1989 by Tim Berners-Lee </li></ul><ul><li>1993, National Center for Supercomputing Applications (NSF) releases the Mosaic browser </li></ul><ul><li>Developers of Mosaic release Netscape (1994) </li></ul>
    49. 50. The Internet vs. The Web <ul><li>Internet – part of the system that is primarily hardware infrastructure (telecommunications, routers, servers, disk drives, etcetera) </li></ul><ul><li>Web – part of the system that contains intellectual property in many formats (text files, graphic files, sound files, video files, etc.) </li></ul><ul><li>The Internet existed before the WWW interface – people used command line programs </li></ul>
    50. 51. Future of the Internet <ul><li>Large Scale Networking (LSN): </li></ul><ul><ul><li>Research and development of cutting-edge networking and wireless technologies </li></ul></ul><ul><li>Internet2: </li></ul><ul><ul><li>Project sponsored by universities, government, and industry to develop new Internet technologies </li></ul></ul><ul><ul><li>Internet2 backbone supports transmission speeds of 9.6 Gbps </li></ul></ul>
    51. 52. Internet Access Security <ul><li>&quot;always on&quot; is security risk - turn the computer off! </li></ul><ul><li>keep OS and anti-virus software up to date </li></ul><ul><li>USE firewall software </li></ul><ul><li>browser security settings </li></ul><ul><li>for LAN, use NAT - router Network Address Translation </li></ul><ul><li>virtual private network (VPN) </li></ul>
    52. 53. Issue: Free Wi-Fi access <ul><li>Some people offer wireless access for free to the community </li></ul><ul><li>A good point - people who can't afford to pay for it can use it </li></ul><ul><li>Broadband providers don't like people giving it away for free </li></ul><ul><li>A bad point - can be used for illegal activities </li></ul>