World Library  
Flag as Inappropriate
Email this Article

I-number

Article Id: WHEBN0001134177
Reproduction Date:

Title: I-number  
Author: World Heritage Encyclopedia
Language: English
Subject: Extensible resource identifier, XRDS, OpenID, Identifiers
Collection: Identifiers
Publisher: World Heritage Encyclopedia
Publication
Date:
 

I-number

i-numbers are a type of Internet identifier designed to solve the problem of how any web resource can have a persistent identity that never changes even when the web resource moves or changes its human-friendly name. For example, if a web page has an i-number, and links to that page use the i-number, then those links will not break even if the page is renamed, the website containing the page is complete reorganized, or the page is moved to another website.

Conceptually, an i-number is similar to an IP address, except i-numbers operate at a much higher level of abstraction in Internet addressing architecture. But the other key difference between the two is that i-numbers are persistent, i.e., once they are assigned to a resource, they are never reassigned. By contrast, IP addresses are constantly reassigned, i.e., your computer may have a different IP address every time it connects to the Internet.

Technically, an i-number is one form of an i-name.

The i-number form of an XRI is designed to serve as an address that does not need to change no matter how often the location of a resource on (or off) the Internet changes. XRIs accomplish this by adding a third layer of abstract addressing over the existing layers: IP numbering (first layer) and DNS naming (second layer). The notion of a third layer for persistent addressing is not new — Uniform Resource Names (URNs) and other persistent identifier architectures have been developed for this purposes. However the XRI layer is the first architecture that combines a uniform syntax and resolution protocol for both persistent and reassignable identifiers.

At the XRI addressing layer, most resources will have both i-names and i-numbers. These different XRIs that all point to the same resource are called synonyms. I-name synonyms make it easy for humans to discover and address the resource, while i-number synonyms make it easy for machines to maintain a persistent identity for the resource. For example, if a company changes its name, it may register a new i-name and sell its old i-name to another company, however its i-number can remain the same — and links to the company that use its i-number won't break.

Furthermore, all of these forms of XRI synonyms can be resolved using the same http- or https-based resolution protocol. The results of XRI resolution are an XML document called an XRDS (Extensible Resource Descriptor Sequence). XRDS documents are the basis for the Yadis identity service discovery protocol that is now part of OpenID.

XRIs are also backwards compatible with the DNS and IP addressing systems, so it is possible for domain names and IP addresses to be used as i-names (or, in rare cases, as i-numbers). Like DNS names, XRIs can also be delegated, i.e., nested multiple levels deep, just like the directory names on a local computer file system. For example, a company can register a top-level (global) i-name and i-number for itself, and then assign second- or lower-level (community) i-names and i-numbers to its divisions, employees, etc.

Examples

The following examples conform to the i-number specifications published in the XDI.org Global Services Specifications. Note that they do not include the 'xri:// prefix as this is optional with absolute XRIs.

Global I-Numbers

  • =!1000.a1b2.93d2.8c73 (Personal)
  • @!1000.9554.fabd.129c (Organizational)
  • !!1000 (Network — reserved for XDI.org-accredited i-brokers)

Community i-numbers (second-level)

  • =!1000.a1b2.93d2.8c73!3ae2 (Personal)
  • @!1000.9554.fabd.129c!2847.df3c (Organizational)
  • !!1000!de21.4536.2cb2.8074 (Network)

Community i-numbers (third-level)

  • =!1000.a1b2.93d2.8c73!3ae2!1490 (Personal)
  • @!1000.9554.fabd.129c!2847.df3c!cfae (Organizational)
  • !!1000!de21.4536.2cb2.8074!9fcd (Network)

See also

External links

  • OASIS XRI Technical Committee
  • OASIS XDI Technical Committee
  • XDI.org
  • XDI.org Global Services Specifications.
  • The Social Web: Creating An Open Social Network with XDI in the Planetwork Journal.
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.