Throttled data transfer, also known as data transfer throttling or lean data transfer, is the deliberate regulation of the data transfer rate in a communications system. Data transfer throttling can be used in any scenario where it is necessary or desirable to limit the amount of data that can be sent or received per unit time.
Data transfer throttling is often used to prevent spam or bulk e-mail transmission through a network server. If the number of e-mail messages sent through the server is limited to, say, one destination address per minute, it is impossible for that server to effectively operate as a medium for the transmission of spam because it would take weeks or months to transfer the number of messages necessary for effective spam marketing.
Data transfer throttling can be used to prevent the uploading or downloading of e-mail messages with large attachments that could otherwise overwhelm an e-mail server. Throttling can be also be useful for public Internet access kiosks, wireless hot spots, public libraries and Internet cafes to prevent "bandwidth hogging" by individual users.
If implemented on a large enough scale, data transfer throttling can control the spread of computer viruses, worms or other malware through the Internet. When used for this purpose, a data transfer throttling program is called a virus throttleor malware throttle.