(Upload/Download ratio, Uplink/Downlink ratio) The difference in speed between transmitting and receiving. For Internet access, the upload speed (from the user) is typically considerably lower than the download speed (to the user). For example, in requesting a Web page, the user uploads a brief text query to the site, which can result in downloading a huge amount of text and graphics back to the user. A video download starts with a short upload request that can cause a download 10,000 times larger.

With satellite-based Internet access, technically, the uploaded data are travelling via the uplink, and the downloaded data travel via the downlink. However, in practice, both terms are used synonymously to refer to the speed ratio or to the data rate in general. See upload and uplink.