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So You Want to Know
About -
Web Accelerators
A web accelerator is a proxy server
that reduces web site access times. They can be a self-contained hardware
appliance or installable software.
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 preemptively resolve
hostnames present in a document (HTML or Javascript)
in order to reduce latency.
·
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 optimize the code from
certain documents (such as HTML or Javascript).
·
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.
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.
These type of server side
accelerators such as Arahe SiteCelerate
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.
It is essential when selecting a web
accelerator product that you take time to find the most suitable accelerator
based on your needs and system setup. Not all accelerators will run on all
operating systems and some may be optimised for a
specific browser configuration.
It is important to check which
internet connections the web accelerator is designed to work with. In some
cases selecting the wrong product will reduce your internet connection speed
dramatically.
The table below shows a number of
web accelerators available:
|
|
Compression |
Operating |
Browser |
Caching |
Prefetching |
Optimize |
Preemptive |
Client |
Connection |
Price |
|
None |
Windows, Mac, Linux and |
Firefox |
Yes |
Yes |
No |
No |
user |
Dialup, Wireless, Broadband, DSL |
Free |
|
|
Text & Images |
? |
Any |
Yes |
Yes |
No |
No |
user/ISP |
Any |
Per CPU |
|
|
Text & Images & Flash &
Office Docs |
Windows, Mac and |
Any |
No |
No |
No |
No |
user |
Dialup, Wireless, Broadband, DSL |
$49.99 (US) |
|
|
Text & Images & Flash &
Office Docs |
Windows, Mac, Mobile devices |
Any |
Yes |
Yes |
No |
No |
user |
Dialup, Wireless, Broadband, DSL |
$47.88 Yearly or $5.95 Monthly |
|
|
Yes |
Windows |
Explorer, Firefox |
Yes |
Yes |
No |
No |
user/Google server |
Broadband |
Free |
|
|
Images, Text, Email, HTTP downloads |
Windows, Mac |
Explorer, Firefox,
Opera, Netscape |
Yes |
No |
No |
No |
End User, ISP |
Dial, DSL, ISDN, Satellite, wireless |
$44.95 US per year. Free with many ISP
subscriptions |
|
|
Text & Images |
Windows, Linux, MacOS,
Symbian, WindowsMobile |
Any |
No |
No |
No |
No |
user/ISP |
Any |
Free |
|
|
Images and email attachments |
Windows, except NT and 95 |
Internet Explorer 5.0 or higher |
? |
? |
No |
No |
ISP |
Dial-up |
local rate |
|
|
Images, text & any gzippable data |
Unix (Linux, *BSD, others) |
Any |
No |
No |
HTML |
Yes |
ISP |
Any |
Free |
|
|
Images, Text, Email, HTTP downloads |
Windows, Mac |
Explorer, Firefox,
Opera, Netscape |
Yes |
No |
No |
No |
End User, ISP |
Dial-up, Broadband, DSL, ISDN,
Satellite, Wireless |
£24.99 |