7. IANA Considerations
7.1. URI Scheme
This section updates the registration of the "urn" URI scheme in the
Permanent URI Registry [URI-Registry].
URI Scheme Name: urn
URI Scheme Syntax: See Section 2 of RFC 8141.
URI Scheme Semantics: The "urn" scheme identifies Uniform Resource
Names, which are persistent, location-independent resource
Encoding Considerations: See Section 2 of RFC 8141.
Applications/Protocols That Use This URI Scheme Name: Uniform
Resource Names are used in a wide variety of applications,
including bibliographic reference systems and as names for
Extensible Markup Language (XML) namespaces.
Interoperability Considerations: See Section 4 of RFC 8141.
Security Considerations: See Sections 6.4.4 and 8 of RFC 8141.
Contact: URNBIS working group [mailto:firstname.lastname@example.org]
Author/Change Controller: This scheme is registered under the IETF
tree. As such, the IETF maintains change control.
7.2. Registration of URN Namespaces
This document outlines the processes for registering URN namespaces
and has implications for the IANA in terms of registries to be
maintained (see especially Section 6). In all cases, the IANA ought
to assign the appropriate NID (formal or informal) once the
procedures outlined in Section 6 have been completed.
7.3. Discussion List for New and Updated NID Registrations
As discussed elsewhere in this document, the discussion list
specified in RFC 3406 (email@example.com) is discontinued and
replaced by the discussion list firstname.lastname@example.org.
Appendix A. Registration Template
Namespace Identifier: Requested of IANA (formal) or assigned by IANA
Version: The version of the registration, starting with 1 and
incrementing by 1 with each new version.
Date: The date when the registration is requested of IANA, using the
Registrant: The person or organization that has registered the NID,
including the name and address of the registering organization, as
well as the name and contact information (email, phone number, or
postal address) of the designated contact person. If the
registrant is a recognized standards development organization,
scientific society, or similar body requesting the fast-track
registration procedure (see Section 6.3), that information should
be clearly indicated in this section of the template.
Purpose: Described in Section 6.4.1 of this document.
Syntax: Described in Section 6.4.2 of this document. Unless the
registration explicitly describes the semantics of r-components,
q-components, and f-components in the context of this URN
namespace, those semantics are undefined.
Assignment: Described in Section 6.4.3 of this document.
Security and Privacy: Described in Section 6.4.4 of this document.
Interoperability: Described in Section 6.4.5 of this document.
Resolution: Described in Section 6.4.6 of this document.
Documentation: A pointer to an RFC, a specification published by
another standards development organization, or another stable
document that provides further information about this URN
Additional Information: Described in Section 6.4.7 of this document.
Revision Information: Description of changes from prior version(s).
(Applicable only when earlier registrations have been revised.)
Appendix B. Changes from RFC 2141
This document makes substantive changes from the syntax and semantics
B.1. Syntax Changes from RFC 2141
The syntax of URNs as provided in [RFC2141] was defined before the
updated specification of URIs in [RFC3986]. The definition of URN
syntax is updated in this document to do the following:
o Ensure consistency with the URI syntax.
o Facilitate the use of URNs with parameters similar to URI queries
o Permit parameters influencing URN resolution.
o Ease the use of URNs with non-URN identifier systems that include
the "/" character.
In particular, this specification does the following:
o Extends URN syntax to explicitly allow the characters "/", "?",
and "#", which were reserved for future use by RFC 2141. This
change also effectively allows several components of the URI
syntax although without necessarily tying those components to URI
o Defines general syntax for an additional component that can be
used in interactions with a URN resolution service.
o Disallows "-" at the end of the NID.
o Allows the "/", "~", and "&" characters in the NSS.
o Makes several smaller syntax adjustments.
B.2. Other Changes from RFC 2141
o Formally registers "urn" as a URI scheme.
o Allows what are now called r-components, q-components, and
In addition, some of the text has been updated to be consistent with
the definition of URIs [RFC3986] and the processes for registering
information with the IANA [RFC5226], as well as more modern guidance
with regard to security [RFC3552], privacy [RFC6973], and identifier
Appendix C. Changes from RFC 3406
This document makes the following substantive changes from [RFC3406]:
1. Relaxes the registration policy for formal URN namespaces from
"IETF Review" to "Expert Review" as discussed in Section 6.2.
2. Removes the category of experimental URN namespaces, consistent
with [RFC6648]. Experimental URN namespaces were denoted by
prefixing the namespace identifier with the string "X-". Because
experimental URN namespaces were never registered, removing the
experimental category has no impact on the existing registries.
Because experimental URN namespaces are not managed, strings
conforming to URN syntax within experimental URN namespaces are
not valid URNs. Truly experimental usages may, of course, employ
the "example" namespace [RFC6963].
3. Adds some information to, but generally simplifies, the URN
namespace registration template.
Many thanks to Marc Blanchet, Leslie Daigle, Martin Duerst, Juha
Hakala, Ted Hardie, Alfred Hoenes, Paul Jones, Barry Leiba, Sean
Leonard, Larry Masinter, Keith Moore, Mark Nottingham, Julian
Reschke, Lars Svensson, Henry S. Thompson, Dale Worley, and other
participants in the URNBIS working group for their input. Alfred
Hoenes in particular edited an earlier draft version of this document
and served as co-chair of the URNBIS working group.
Juha Hakala deserves special recognition for his dedication to
successfully completing this work, as do Andrew Newton and Melinda
Shore in their roles as working group co-chairs and Barry Leiba in
his role as area director and then as co-chair.
RFC 2141, which provided the basis for the syntax portion of this
document, was authored by Ryan Moats.
RFC 3406, which provided the basis for the namespace portion of this
document, was authored by Leslie Daigle, Dirk-Willem van Gulik,
Renato Iannella, and Patrik Faltstrom.
Their work is gratefully acknowledged.
P.O. Box 787
Parker, CO 80134
United States of America
Phone: +1 720 256 6756
John C. Klensin
1770 Massachusetts Ave, Ste 322
Cambridge, MA 02140
United States of America
Phone: +1 617 245 1457