Uniform Resource Identifier (URI): compact sequence of characters that identifies an abstract or physical resource.
Syntax:
URI = scheme ":" hier-part [ "?" query ] [ "#" fragment ]
hier-part = "//" authority path-abempty
/ path-absolute
/ path-rootless
/ path-empty
example:
foo://example.com:8042/over/there?name=ferret#nose
\_/ \______________/\_________/ \_________/ \__/
| | | | |
scheme authority path query fragment
| _____________________|__
/ \ / \
urn:example:animal:ferret:nose
"Uniform Resource Locator" (URL):
Refers to the subset of URIs, in addition to identifying a resource, provide a means of locating the resource by describing its primary access mechanism.
"Uniform Resource Name" (URN):
Intended to serve as persistent,location-independent, resource identifiers.
All URNs have the following syntax (phrases enclosed in quotes are
REQUIRED):
<URN> ::= "urn:" <NID> ":" <NSS>
where <NID> is the Namespace Identifier, and <NSS> is the Namespace Specific String.
Refer below:
https://tools.ietf.org/html/rfc3986
https://tools.ietf.org/html/rfc2141
https://en.wikipedia.org/wiki/Uniform_Resource_Identifier
