What is URN?

URN stands for Uniform Resource Name. It's a type of identifier for resources on the internet. A URN is used to uniquely identify resources without implying their location or how to access them.

Structure of URN

A URN follows a specific format consisting of three parts:

urn:NID:Namespace-Specific String

where;

• urn: This indicates it's a Uniform Resource Name.
• Namespace Identifier (NID): This identifies the system or organization that created the URN. For example, "isbn" for International Standard Book Number.
• Namespace-Specific String: This uniquely identifies the resource within the namespace. For example, "0-300-12345-6" could be the specific book number within the ISBN namespace.

For example:

• urn:isbn:0451450523 - Identifying a book by its International Standard Book Number (ISBN).
• urn:ietf:rfc:2648 - Identifying an Internet Engineering Task Force (IETF) Request for Comments (RFC).

URN vs URL

You may realize similarities URNs with URLs. However, there are some key differences between the two:

• Focus: URNs focus on identifying a resource uniquely and persistently, even if the location of the resource changes or it becomes unavailable. URLs, on the other hand, are primarily concerned with locating a resource at a specific address.
• Structure: URNs follow a specific format that starts with "urn:" followed by a namespace identifier and a namespace-specific string. URLs have a more flexible structure that includes protocol (like http or ftp), domain name, and path.
• Persistence: URNs are designed to be persistent, meaning they should remain valid for a long time regardless of the resource's location. URLs can become outdated if the resource they point to moves or is deleted.

In simpler terms, think of URNs like labels that uniquely identify things, and URLs like addresses that tell you how to find those things.

Here's an example:

• A URN for a book in the Library of Congress might look like: urn:isbn:0-300-12345-6
• A URL for the same book on a library website might be: https://www.library.com/books/0-300-12345-6

While URNs aren't used for directly locating resources like URLs, they play a vital role in various areas like identifying digital objects, scientific data, and entities in security systems.

Conclusion

In summary, a URN provides a standardized way to uniquely identify resources by name in a persistent and location-independent manner.

URNs are often used in contexts where resource identification needs to be stable and not tied to a specific location. This is particularly useful in scenarios such as digital libraries, persistent identifiers for scholarly articles, and other long-term referencing needs.

Thank you for reading.