Protocols

URLs are used in a number of circumstances, to retrieve data using many techniques for many purposes. For example, they are used for e-mail, for file transfer and for USENET news. The first part of the URL therefore gives an indication of the scheme it belongs to. The scheme, or protocol, is separated from the rest of the URL using a colon:

					protocol:scheme-specific-part

The protocols for the uses given above are 'mailto:', 'ftp:' (File Transport Protocol) and 'news:':

mailto:scheme-specific-part

ftp:scheme-specific-part

news:scheme-specific-part

The syntax of the remainder of the URL depends on the requirements and characteristics of the scheme involved. Here, the discussion concentrates on the file URL scheme and HTTP URL scheme, ...

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