The Technology Behind SiteCelerate

Five main things SiteCelerate/Netcelerate does that are better than plain web caches or TCP level compression:

1. All HTTP responses are reformatted by SiteCelerate/NetCelerate to allow persistent connections. Most http responses created by web servers, especially at dynamically created websites, do not have the correct HTTP headers to keep a persistent connection open. Standard web caches and TCP level compression do not perform this function. This is EXTREMELY important when a slow connection is involved.



2. HTML/CSS/JAVASCRIPT text will be compressed 80% to 90%, which is more than packet-by-packet TCP level compression can do. Because we see whole objects and not just bits and pieces, SiteCelerate/NetCelerate can consider more data in the compression algorithm. Also, standard web caches can't handle compressed text and have to drop it each time because they can't serve compressed text to all browsers. Our system is able to uncompress the text for those users on older browsers who need the uncompressed version.



3. Images are reformatted and compressed using the most efficient algorithm, switching from GIF to JPG and JPG to GIF when gains can be made without affecting image quality. As data, a TCP level compressor will not be able to make that high level evaluation and change over. Standard web-caches just resend the same image in the wrong format again and again.



4. All web page images are checked for longevity and if they are stable objects, the HTTP headers are modified using the Optiview system to make them more cacheable at the browser. This means that on subsequent visits to a page, the number of "if modified since the last visit" requests are greatly reduced. By reducing these additional requests, SiteCelerate/NetCelerate speeds up the process of loading the objects that may have changed.



5. All web objects (Pages/scripts/images) are "fingerprinted" and if a user has already downloaded the exact object that the web server is serving up for a second load, SiteCelerate/NetCelerate is able to transform that request into a "Not Modified" response. This not only works for static objects, but also for dynamically created pages and content tagged as private. Web servers and standard web-caches discard data about dynamic and private objects, but OptiView's SiteCelerate/NetCelerate system is able to accurately track this transparently for all users and detect the same information is being re-served. This process can take a 50K page load response and transform it to a 200byte response for a huge savings.

For example, tests have shown that download times on standard 56K dialup lines can be reduced by at least 50%. We used a page loading program to load a list 231 web pages provided by an ISP, with and without SiteCelerate/NetCelerate, Starting with a clear cache before each set of three passes. This particular test was done with the SiteCelerate/NetCelerate in a POP 2300 miles away and clearly shows what can be done with a semi-remote installation. A local installation would do much better.

Without NetCelerate

Pass 1 102 minutes, 4497 http accesses

Pass 2 38 minutes, 3972 http accesses

Pass 3 33 minutes, 4006 http accesses

 

With NetCelerate

Pass 1 39 minutes, 3794 http accesses

Pass 2 22 minutes, 1197 http accesses

Pass 3 18 minutes, 1031 http accesses

 

Total: 51% time-savings, 52% reduction in http accesses. You can always try it first: Contact us now for a no-obligation test on your systems.