SOC2 Definitions 2 slide-6

Uniform Resource Identifier (URI)

Not just a fancy name for a URL.

There are also Uniform Resource Names (URNs): unique names for things. Here are some examples.

Digital Object Identifiers (DOIs), such as doi:10.3390/fi3010049
can be accessed by most modern web browsers and special DOI resolvers such as dx.doi.org.

International Standard Serial Number (ISSN) is used to uniquely identify periodical publications.
Example: urn:issn:1534-0481. Resolver at http://bioguid.info/issn/.

Life Science Identifiers (LSIDs) help biologists understand the current taxonomies of species.
Example: urn:lsid:ipni.org:names:20012728-1:1.1 Resolver at http://bioguid.info/lsid.php.

International Standard Audiovisual Numbers (ISANs) identify audivisual media.
Example: urn:isan:0123-1230-3210-2310-1. No known public resolver.

There are many today. Soon people will have them.

URLs specify a location where the resource can be found and accessed.
URNs often include a URL in the metadata for the URN.
Then the URL can change, but the URN will always be correct.
REST uses URIs to pass information back and forth between the client and server.
The server will create URIs to convey new information.