A web accelerator is a proxy server that reduces website access time. They can be a self-contained hardware appliance or installable software. Web accelerators may be installed on the client computer or mobile device, on ISP servers, on the server computer/network, or a combination. Accelerating delivery through compression requires some type of host-based server to collect, compress and then deliver content to a client computer.

Techniques

Web accelerators may use several techniques to achieve this reduction in access time: They may: * cache recently or frequently accessed

documents A document is a writing, written, drawing, drawn, presented, or memorialized representation of thought, often the manifestation of nonfiction, non-fictional, as well as fictional, content. The word originates from the Latin ''Documentum'', w ...

so they may be sent to the client with less latency or at a faster

transfer rate In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time. The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction w ...

than the remote server could. *freshen objects in the cache ensuring that frequently accessed content is readily available for display. *preemptively resolve hostnames present in a document ( HTML or JavaScript) in order to reduce latency. *

prefetch Prefetching in computer science is a technique for speeding up fetch operations by beginning a fetch operation whose result is expected to be needed soon. Usually this is before it is ''known'' to be needed, so there is a risk of wasting time by p ...

documents that are likely to be accessed in the near future. * 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. * optimize the code from certain documents (such as HTML or JavaScript). * filter out ads and other undesirable objects so they are not sent to the client at all. *maintain persistent

TCP TCP may refer to: Science and technology * Transformer coupled plasma * Tool Center Point, see Robot end effector Computing * Transmission Control Protocol, a fundamental Internet standard * Telephony control protocol, a Bluetooth communication s ...

connections between the client and the proxy server. *improve the performance via protocol level accelerations, such as TCP acceleration. These techniques align with best practices which are typically recommended to improve the performance of web applications.

Web client accelerator

Introduced in 2001-200

these applications generally serve to improve

dial-up Dial-up Internet access is a form of Internet access that uses the facilities of the public switched telephone network (PSTN) to establish a connection to an Internet service provider (ISP) by dialing a telephone number on a conventional telepho ...

, broadband and other connections from which users may not be getting the best speed. Many Dialup ISPs offer web accelerators as a part of their services. The pre-compression operates much more efficiently than the on-the-fly compression of V.44 modems. Typically, website text is compacted to 5%, thus increasing effective dialup throughput to approximately 1000 kbit/s, and JPEG/GIF/PNG images are lossy-compressed to 15–20%, increasing effective throughput to 300 kbit/s. The drawback of this approach is a loss in quality, where the graphics acquire compression artifacts taking on a blurry or colorless appearance. However, the transfer speed is dramatically improved. If desired, the user may choose to view uncompressed images instead, but at a much slower load rate. Web accelerators are typically designed for web browsing and, sometimes, for e-mailing and can not improve speeds of

streaming Streaming media is multimedia that is delivered and consumed in a continuous manner from a source, with little or no intermediate storage in network elements. ''Streaming'' refers to the delivery method of content, rather than the content it ...

, 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

small and medium enterprises Small and medium-sized enterprises (SMEs) or small and medium-sized businesses (SMBs) are businesses whose personnel and revenue numbers fall below certain limits. The abbreviation "SME" is used by international organizations such as the World Bank ...

List

America Online AOL (stylized as Aol., formerly a company known as AOL Inc. and originally known as America Online) is an American web portal and online service provider based in New York City. It is a brand marketed by the current incarnation of Yahoo! Inc. ...

Netscape Netscape Communications Corporation (originally Mosaic Communications Corporation) was an American independent computer services company with headquarters in Mountain View, California and then Dulles, Virginia. Its Netscape web browser was onc ...

ISP * Google Web Accelerator (discontinued) * Heigh Speed (discontinued) *

NetJet NetJet was the first commercially available web accelerator. The product was developed by Peak Technologies (changed in 1997 to PeakSoft Multinet Corp.) in 1996 and released in November 1996 at COMDEX in Las Vegas Nevada. NetJet was named a 'Best ...

(discontinued) * OnSpeed (discontinued) *

Polipo Polipo is a lightweight caching and forwarding web proxy server. It has a wide variety of uses, from aiding security by filtering traffic; to caching web, DNS and other computer network lookups for a group of people sharing network resources; ...

(not maintained) *

Squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...

* WinGate * Ziproxy

Web server accelerator

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. Web server accelerators are sometimes referred to as

reverse proxies In computer networks, a reverse proxy is the application that sits in front of back-end applications and forwards client (e.g. browser) requests to those applications. Reverse proxies help increase scalability, performance, resilience and securi ...

or Application Delivery Controllers. This type of server side accelerator has the added benefit of off-loading transactions and connection managements from the web or applications servers and hence, reducing its CPU utilization and increasing web server or application scalability to handle more users with less bandwidth.

List

aiScaler aiScaler Ltd. is a multinational software company founded in 2008. It develops application delivery controllers designed to allow dynamic web pages to scale content by intelligently caching frequently requested content. A number of websites in ...

* Apache

Traffic Server The Apache Traffic Server (ATS) is a modular, high-performance reverse proxy and forward proxy server, generally comparable to Nginx and Squid. It was created by Inktomi, and distributed as a commercial product called the Inktomi Traffic Ser ...

* CACHEbox * nginx *

(not maintained) *

Varnish Varnish is a clear transparent hard protective coating or film. It is not a stain. It usually has a yellowish shade from the manufacturing process and materials used, but it may also be pigmented as desired, and is sold commercially in various ...

* Ziproxy

Client–server

There may be two sections to the proxy as well - a server portion sits in front of the

web server A web server is computer software and underlying hardware that accepts requests via HTTP (the network protocol created to distribute web content) or its secure variant HTTPS. A user agent, commonly a web browser or web crawler, initiate ...

and captures the input and output from the server and a client portion sits in front of the end-user's web browser to capture the input and output from the browser. An example would be Opera Turbo.

References

External links

* {{DEFAULTSORT:Web Accelerator

Techniques

Web client accelerator

List

Web server accelerator

List

Client–server

See also

References

External links