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By Dan Backman
When Spectrum Information Technologies first said it could double Web download speeds for dial-in clients without installing client software or affecting the dial-up connections, I didn't believe it. But the company's FastLane Download Accelerator lives up to the claim. However, with this product you have to remember that you don't get something for nothing.
FastLane speeds downloads by reformatting Web graphics. Emulating a proxy server, FastLane intercepts GIF and JPEG images, subjecting them to heavy, lossy compression before they're passed to the client. But buyer beware: This compression does affect image quality. We don't s
uggest forcing this on your users.
I tested FastLane in Network Computing's Syracuse University lab and was impressed with FastLane as a Web accelerator, but not with the quality of the images generated.
FastLane runs as a Windows NT 4.0 service, listening on a high TCP port for incoming HTTP proxy requests from clients. Other than port selection, FastLane requires almost no configuration and was almost ridiculously simple to get running. I set up two Windows95 workstations connected to a Shiva LANrover/E Plus remote-access server using V.34 28.8-Kbps modems via line simulators (to ensure optimal line quality). FastLane doesn't affect the dial-up client or the remote-access server. Clients must only specify the FastLane server's host name or IP address and the specified TCP port. I tested clients using both Netscape Communicator 4.04 and Microsoft Internet Explorer 4.01.
Moving Right Along
In the best-case scenario (accessing a local Web server and highly graphic content), Web pages were down
loaded in roughly half the time with FastLane. But results on different Web sites throughout the Internet varied. On average, FastLane decreased download times by about one-third.
FastLane does not handle GIF and JPEG image compression well. Because GIF and JPEG graphics are inherently noncompressible (they're already heavily compressed), FastLane must take liberties with image color depth and detail level. Close examination shows some fuzziness and mosaic effects (tiling) in JPEG images and noticeably reduced color depth in GIF images. The beta version I tested occasionally misinterpreted GIF color palettes. Spectrum says its compression algorithms are still being fine-tuned.
Although FastLane operates as an HTTP proxy server, scanning the MIME types of all Web documents looking for GIF and JPEG images, you shouldn't mistake it for a caching proxy server. FastLane is specifically designed to compress GIF and JPEG images on the fly. Each encountered GIF and JPEG image is received by the FastLane server,
decoded, heavily compressed, re-encoded and passed to the client. All processes are done in memory, and nothing is cached to disk. However, FastLane does include a convenient upgrade path, as it can relay HTTP proxy requests to an external proxy server. This lets you use FastLane's acceleration while tying into a proxy server to utilize caching or centralized logging. In addition, FastLane lets you control the level of image compression, which can mitigate image degradation in favor of slightly larger images.
Dan Backman can be reached at dbackman@nwc.com.
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