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ERPANET-Workshop „Persistent Identifiers“ (17th June 2004) Uniform Resource Names (URN) – Overview. Die Deutsche Bibliothek Kathrin Schroeder. Starting Point: Naming Schemes / Namespaces and Resolution. Naming Schemes and Namespaces (Identification)
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ERPANET-Workshop „Persistent Identifiers“ (17th June 2004) Uniform Resource Names (URN) – Overview Die Deutsche Bibliothek Kathrin Schroeder
Starting Point: Naming Schemes / Namespaces and Resolution • Naming Schemes and Namespaces (Identification) • Uniform Resource Identifiers (URI), Uniform Resource Locators (URL) • Uniform Resource Names (URN) • further Persistent Identifiers • XML namespaces • ... • Resolution of names (Resolution mechanims) • HTTP (Redirect etc.) • DNS (Domain Name System) • ... • Standardisation / Social Infrastructure
Terminology – the „Classical view“ RFC 2396 URI - Uniform Resource Identifier Identification of an abstract or physical resource URN - Uniform Resource Name URL - Uniform Resource Locator URC - Uniform Resource Characteristic • Identification of a resource • Provision a means of locating the resource by describing its primary access mechanism Persistent naming of resources. Characteristics of a resource e.g. meta information
Terminology – the „Contemporary view“ • Report from the Joint W3C/IETF Planning Interest Group • - RFC 3305 • Motivation: • - Confusion in the web community over the partitioning of URI space, • specifically, the relationship among the concepts of URL, URN, and URI. • Recommendations: • The importance of this additional level of hierarchy seemed to be • lessen. • The W3C and IETF should jointly develop and endorse a model for • URIs, URLs, and URNs consistent with the „Contemporary View“. • Generalized registration procedures for all URI schemes • [...] • <http://www.ietf.org/rfc/rfc3305.txt>
Registered URI-Schemes Scheme Name Description Reference -------------------- ----------------------------------------- ---------------- urn Uniform Resource Names [RFC2141] (please see: http://www.iana.org/assignments/urn-namespaces) ftp File Transfer Protocol [RFC1738] http Hypertext Transfer Protocol [RFC2616] [... more than 40 URI SCHEMES] http://www.iana.org/assignments/uri-schemes (last updated 2004-01-26)
URN-Framework URN Syntax 2141 1737 3406, 2611, 2288, 3188, 3187... 3401-3406 Functional Requirements for URNs Request for Comments (RFC) Registration of NIDs Resolution
URN – Syntax (RFC 2141) <URN>::=„URN“:“<NID>“:“<NISS> URN: resolution routine NID: namespace identifier e.g. ISBN, ISSN und NBN NISS: namespace specific string Example: urn:nbn:de:gbv:089-3321752945 <http://www.ietf.org/rfc/2141.txt>
URN-Framework URN Syntax 2141 1737 3406, 2611, 2288, 3188, 3187... 3401-3406 Functional Requirements for URNs Request for Comments (RFC) Registration of NIDs Resolution
Functional Requirements for URNs (RFC 1737) • Functional Requirements • Global scope • Global uniqueness • Persistence • Scalability • Legacy support • Extensibility • Independence • Resolution • Requirements for Encoding • Implications
URN-Framework URN Syntax 2141 1737 3406, 2611, 2288, 3188, 3187... 3401-3406 Functional Requirements for URNs Request for Comments (RFC) Registration of NIDs Resolution
Namespace Definition and Registration (RFC 3406) • Assumptions • Assignment of a URN is a managed process. • The space of URN namespaces is managed. • Templates for URN-namespace registration: • Experimental Namespaces • Informal Namespaces • Formal Namespaces • Considerations include: • - URN assignment procedures • - URN resolution/delegation • - Type of resources to be identified • - Type of services to be supported • - Community considerations • Review by mailing-list urn-nid@apps.ietf.org
Examples of registered URN-Namespaces • RFC 2648: A URN Namespace for IETF Documentsurn:ietf:rfc:2141 • RFC 3044: Using The ISSN (International Serial Standard Number) as URN (Uniform Resource Names) within an ISSN-URN Namespace urn:ISSN:0259-000X • RFC 3188:Using National Bibliography Numbers as Uniform Resource Namesurn:nbn:fi-fe19981001 [... 21 Namespaces] <http://www.iana.org/assignments/urn-namespaces>
URN-Framework URN Syntax 2141 1737 3406, 2611, 2288, 3188, 3187... 3401-3406 Functional Requirements for URNs Request for Comments (RFC) Registration of NIDs Resolution
Dynamical Delegation to URN services via DNS (RFC 3401 - 3404) urn.arpa (Top Level) URN-REQUEST urn:ietf:.. urn:nbn:... [...] ietf nbn 19 ... au se de ch fi hu ... Examples „register@urn.arpa“: VeriSign „pin“ Voice over IP (ENUM)
The client (Browser) perspective … Plugins (Example) http://www.persistent-identifier.de/?link=550 Other technical solutions exist ...
And the Future ? Discussion points • Steady browser implementation of PIs/URNs • Development of a PI independent browser-plugin • Continuing the co-operation between IANA/IETF/W3C • Interfaces between several PI-Resolution mechanisms Thank you!schroeder@dbf.ddb.de