A complete URI consists of a naming scheme specifier followed by a string whose format is a function of the naming scheme. For locators of information on the Internet, a common syntax is used for the IP address part. A BNF description of the URL syntax is given in an a later section. The components are as follows. Fragment identifiers and relative URIs are not involved in the basic URL definition.
Within the URI of a object, the first element is the name of the scheme, separated from the rest of the object by a colon.
The rest of the URI follows the colon in a format depending on the scheme. The path is interpreted in a manner dependent on the protocol being used. However, when it contains slashes, these must imply a hierarchical structure.