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  1. 1. How High-speed Dial-up Works<br />
  2. 2. Dial-up connection<br />About while our surfing the Internet<br /><ul><li>If we can do some works, we often use Dial-up connection.</li></ul>What is Dial-up connection?<br /><ul><li>The connection speed of dial-up is limited by the bandwidth of phone lines.
  3. 3. The average file size for Web content is getting larger.
  4. 4. More people are using broadband connections that can handle a bigger load, so Web sites feel more comfortable bulking up their pages.</li></li></ul><li>Software handshake<br />High-speed dial-up<br /><ul><li>It allows your machine to establish a connection with your ISP in a fraction of the time it takes with standard dial-up.
  5. 5. Your request is routed though your ISP to the Web.
  6. 6. The high-speed dial-up data path Acceleration servers speed up the dial-up data transfer using several techniques.</li></li></ul><li>The key element of High-speed Dial-up Works<br />About file type<br /><ul><li>The chart below will help you understand what will and will not be accelerated by high-speed dial-up.</li></ul>Accelerated<br />Not Accelerated<br />HTML/Java-based Web pages<br />Text<br />JPG/GIF-based graphics<br />E-mail<br />Streaming media (audio or video)<br />Secure Web pages<br />Music/photos sent as e-mail attachments<br />Downloads<br /><ul><li>At this point, the on-the-fly file compression utilized in high-speed dial-up can't be</li></ul> added to the file types specified above because of the nature of the data.<br />
  7. 7. The key element of High-speed Dial-up Works<br />how a typical acceleration server compresses different file types<br /><ul><li>For text files, including the HTML text of a Web page and the text in an e-mail </li></ul> message, the acceleration server compresses the text on the fly and sends it <br />down your modem line. Typically, text will compress at least 50 percent using <br />on-the-fly techniques.<br /><ul><li>For image files, including GIF and JPG images on Web pages as well as many </li></ul> banner ads, the acceleration server reads the image from the Web site and <br />recompresses it to reduce its size.Typically, the image file size shrinks <br /> anywhere from 50 percent to 90 percent in the process.<br /><ul><li>In many other files, including video files, Zip files and MP3music files ,</li></ul> compression has already taken place. For example, an MP3 file is already<br /> one-tenth the size of the original track on the CD . It is not possible to compress<br /> the file any further in a quick way. <br />
  8. 8.  Filtering and Caching<br />Filtering<br /><ul><li>If that page uses pop-up advertising, there are pop-up parameters hiding in its programming code. In order for the pop-up to pop, that hidden code must display parameters that tells your machine what size the ad is, where on the screen it should appear, and other details about the ad. These ads take up valuable bandwidth, slowing down the transmission of data to your machine.</li></ul>Filtering<br /><ul><li>To combat this drag, high-speed dial-up providers have bundled a pop-up blocker into the software they send to subscribers. When it sees those tell-tale lines of code, it rejects the ad's request to be displayed. What this amounts to is less information being sent across the phone line to your machine. The less data that is sent, the faster the load time.</li></li></ul><li>Filtering and Caching<br />Caching<br /><ul><li>The first time your browser loads a Web page, it has to load the entire thing, along with all of the images it displays. If the browser saves the images and text, then the second time it loads the same page it can check for duplicates. If an image has not changed, there is no need to download it again. This process of saving a file in the hopes of reusing it in the future is called caching.
  9. 9. It is called server-side caching that Instead of constantly requesting the same page, the acceleration server takes note of which Web pages are being commonly asked for by all subscribers, and it saves time by eliminating redundant requests.
  10. 10. There is a second side to caching -- client-side caching . Internet browsers like Explorer or Netscape are made to cache frequently viewed pages to cut down on load times.</li></ul>Client-side caching<br />
  11. 11. Bottom Line<br />how much the service sped up a dial-up connection<br /><ul><li>how much the service sped up a dial-up connection with using one of the more popular high-speed dial-up providers, NetZero.
  12. 12. As an example, HowStuffWorks came up three times faster with high-speed dial-up.</li></ul> For the complete results, see the chart below.<br />With High Speed Dial-Up<br />With Dial-Up<br />Web Page/ Original Load Time (seconds)/Cached Load Time (seconds)<br />Web Page/ Original Load Time (seconds)<br /><br /><br /><br /><br />Google search (100 results)/9/7.42<br /><br /><br /><br /><br /><br /><br /><br />Google search (100 results)/10.45<br /><br /><br /><br />