Uniform Resource Identifier (URI)

What is a URI?

A URI (Uniform Resource Identifier) is a method of uniquely identifying resources, such as information, services, or devices, through a specific format. URI is commonly used to indicate the location of services or data on the internet.

A URI consists of two main components:

1. A scheme, which serves as an identifier.
2. An authority, which provides information about the resource's identity or location.

For example:

https://f5.com/

In this URI:

• "https" is the scheme.
• ":" separates the scheme and the authority.
• "//f5.com/" is the authority.

The authority can also include a username and password for access, but this is generally avoided for security reasons. Similarly, although port numbers can be specified, they are often omitted because they are typically predefined for each scheme.

Before URIs, the URL (Uniform Resource Locator) was defined as a method for identifying resources on a network. Even today, references to websites on the internet are commonly referred to as URLs. For instance, the URI in the example above is more broadly known as a URL in everyday use.

URI is a broader concept that encompasses URLs as a subset. Another subset of URI is URN (Uniform Resource Name), which is used for persistent identification of resources across various domains. A common example of a URN is the ISBN code, which uniquely identifies books globally.