Metalink is a new open standard format (.metalink) for downloading files. Metalink can combine and store HTTP, FTP and Bittorent P2P download links/mirrors for a downloadable file into one single format -metalink- so that in case one server mirror /protocol/mirror goes down, the download will automatically continue from other protocol/mirror server.

For example, Opera stores its popular browser in various HTTP and FTP locations. Now lets say if the HTTP server goes down temporarily for some reason, the download at the user’s end will still continue from the FTP server.

“Metalinks have several advantages to individual mirrors. First of all, it speeds up the download process. Secondly, downloads are more reliable since metalinks use several mirrors. An additional advantage for the publisher is that he or she is able to prioritize a source.”

Via Readwriteweb