Download acceleration is a process that computer software initiates to increase the speed of a download by creating multiple connections to a single server or host system. The software usually is integrated into a web browser and operates on a hypertext transfer protocol (HTTP) connection. The premise of download acceleration is based on the fact that an HTTP connection could limit the amount of bandwidth that is used by a single connection. Using download acceleration means creating multiple connections to the server, each working in tandem to download different segments of a single large file, or multiple smaller files, simultaneously.
Web servers attempt to increase their efficiency by balancing the load from all of the active connections from users who are requesting information. The practice of limiting the bandwidth of a single connection is meant to allow numerous users to be able to send and receive information without a single connection monopolizing all of the server’s resources. A download accelerator connects multiple times to a server with each connection having the equivalent bandwidth allocated to a single use. This causes the system to assign more bandwidth overall to the accelerator.
Almost all download accelerator software is part of a much more complex download management package. Download managers are capable of parsing a website, isolating all of the media files, then creating multiple connections to download all of the files at the same time. For a single large file, the manager will create multiple connections and download a different segment of the file through each one. Each segment is saved to disk and, upon completion, reconstructed into a single file again.
The concept of download acceleration is similar to segmented downloading. Segmented downloading is used in peer-to-peer file transfer programs. This process involves connecting to multiple peer computers and transferring small segments of a larger file from different sources to distribute the bandwidth usage. This is distinctly different from what a download accelerator does because accelerators connect to only one server.
Download acceleration is not always effective, especially as the speed and availability of bandwidth increases worldwide. If the speed of the connection of the server sending the file is greater than the speed of the connection of the receiving computer, then the acceleration will not work, because it is limited by the receiving speed. Using download accelerators is discouraged by large websites because it can cause the server to become overburdened and reduce the sending speed for all visitors to the site.