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Web accelerators may use several techniques to achieve this reduction:
- They may cache recently or frequently accessed documents so they may be sent to the client with less latency or at a faster transfer rate than the remote server could.
- They may freshen objects in the cache ensuring that frequently accessed content is readily available for display.
- They may prefetch documents that are likely to be accessed in the near future.
- They may compress documents to a smaller size, for example by reducing the quality of images or by sending only what's changed since the document was last requested.
- They may filter out ads and other undesirable objects so they are not sent to the client at all.
- They may maintain persistent TCP connections between the client and the proxy server.
Web accelerators may be installed on the client (browsing) computer / mobile device or on ISP hosted servers or both. Accelerating delivery through compression requires some type of host based server to collect, compress and then deliver content to a client computer.
There may be two sections to the proxy as well - a server portion sits in front of the Web server and captures the input and output from the server and a client portion sits in front of the end-users Web Browser to capture the input and output from the browser.
As of July 2006, these applications generally serve to improve dial-up, broadband and other connections from which users may not be getting the best speed. Many users can achieve a 2- to 10-times speed increase in average browsing experience, while some report a 5- to 20-times speed increases for specific web sites and pages. Many ISPs offer web accelerators as a part of their dial up and broadband services. Web accelerators are typically designed for web browsing and, sometimes, for e-mailing and can not improve speeds of streaming, gaming, P2P downloads or many other Internet applications. However, there is substantial work being done on client-side Web Accelerators for Application Delivery Networks by several companies including Cisco Systems and F5 Networks as the demand for SaaS and PaaS look set to grow among SMEs.
Other web accelerators are targeted at the web site or web application owners. This type of web accelerator is installed in front of web servers and application servers and use a variety of the above techniques to improve performance to all users accessing the accelerated web sites or web applications. Sometimes referred to as a Reverse proxy.
These type of server side accelerators has the added benefit of off-loading transactions and connection managements from the web or applications servers and hence, reducing its CPU utilisation and increasing web server or application scalability to handle more users with less bandwidth.
Since there are so many different PC configurations, it is impossible for any one web accelerator to be the best as an application of its purpose. It is even possible for a web accelerator to slow down and clog up a connection.
|CACHEbox||None||Appliance (Linux)||All||Yes||Yes||No||No||Yes||End user, ISP||Broadband, Satellite, Wireless, Fiber, DSL||Commercial|
|CProxy||Gzip, images||Windows||All||Yes||?||Yes||Yes||Yes||user||up to 756kbps||Free demo, full version 35USD per year|
|FasterFox||None||Windows, Mac, Linux and Mobile devices||Firefox||Yes||Yes||No||No||No||user||Dialup, Wireless, Broadband, DSL||Free|
|fasTun||Images, text & any gzippable data||Any||Any||No||No|| HTML|
|Freewire||Images and email attachments||Windows, except NT and 95||Internet Explorer 5.0 or higher||?||?||No||No||No||ISP||Dial-up||local rate|
|Google Web Accelerator||Yes||Windows||Explorer, Firefox||Yes||Yes||No||No||No||user/Google server||Broadband||Free|
|Netfury||Images, Text, Email, HTTP downloads||Windows, Mac||Explorer, Firefox, Opera, Netscape||Yes||No||No||No||No||End User, ISP||Dial-up, Broadband, DSL, ISDN, Satellite, Wireless||£24.99|
|Nitro||Images, Text, Email, HTTP downloads||Windows, Mac||Explorer, Firefox, Opera, Netscape||Yes||Yes||No||No||No||End User, ISP||Dial-up, Broadband, DSL, ISDN, Satellite, Wireless||$29.95 a year|
|ONSPEED||Text & Images & Flash & Office Docs||Windows, Mac and Mobile devices||Any||No||No||No||No||No||user||Dialup, Wireless, Broadband, DSL|| $49.99 (US)|
Free (for users of BT Yahoo! Dialup Internet in the UK)
|Propel||Images, Text, Email, PDF, HTTP downloads||Windows, Mac||Explorer, Firefox, Opera, Netscape||Yes||No||No||No||No||End User, ISP||Dial, DSL, ISDN, Satellite, wireless||$44.95 US per year. Free with many ISP subscriptions|
|Proxyconn Web Accelerator||Text & Images & Flash & Office Docs||Windows, Mac, Mobile devices||Any||Yes||Yes||No||No||No||user||Dialup, Wireless, Broadband, DSL||$47.88 Yearly or $5.95 Monthly|
|RabbIT||Images, text & any gzippable data||Unix (Linux, *BSD, others), Windows, Mac (generally every system with Java 1.6 VM available)||Any||Yes||No||No||No||Yes||ISP||Any||Free|
|SiteCelerate||Text & Images||?||Any||Yes||Yes||No||No||No||user/ISP||Any||Per CPU|
|Squid||Text & Images||?||Any||Yes||Yes||Yes||Yes||Yes||user/ISP||Any||Per CPU|
|Toonel||Text & Images||Windows, Linux, Mac OS, Symbian, WindowsMobile||Any||No||No||No||No||No||user/ISP||Any||Free|
|Varnish||?||Unix (Linux, *BSD, Mac OS X, others)||Any||?||?||?||?||?||?||Any||Free|
|Ziproxy||Images, text & any gzippable data||Unix (Linux, *BSD, Mac OS X, others)||Any||No||No|| HTML|