Internet DRAFT - draft-ietf-urlreg-procedures
INTERNET-DRAFT R. Petke
<draft-ietf-urlreg-procedures-08.txt> UUNET Technologies
September 26, 1999
Registration Procedures for URL Scheme Names
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. Internet-Drafts are
working documents of the Internet Engineering Task Force (IETF), its
areas, and its working groups. Note that other groups may also
distribute working documents as Internet-Drafts. Internet-Drafts
are draft documents valid for a maximum of six months and may be
updated, replaced, or obsoleted by other documents at any time. It
is inappropriate to use Internet-Drafts as reference material or to
cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
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Distribution of this Internet-Draft is unlimited.
This Internet-Draft expires April 26, 2000.
Copyright (C) The Internet Society (1999). All Rights Reserved.
This document defines the process by which new URL scheme names are
A Uniform Resource Locator (URL) is a compact string representation
of the location for a resource that is available via the Internet.
RFC 2396  defines the general syntax and semantics of URIs, and,
by inclusion, URLs. URLs are designated by including a "<scheme>:"
and then a "<scheme-specific-part>". Many URL schemes are already
defined, however, new schemes may need to be defined in the future
in order to accommodate new Internet protocols and/or procedures.
A registration process is needed to ensure that the names of all
such new schemes are guaranteed not to collide. Further, the
registration process ensures that URL schemes intended for wide
spread, public use are developed in an orderly, well-specified, and
This document defines the registration procedures to be followed
when new URL schemes are created. A separate document, RFC
[URL-GUIDELINES], Guidelines for URL Schemes , provides
guidelines for the creation of new URL schemes. The primary focus
of this document is on the <scheme> portion of new URL schemes,
referred to as the "scheme name" throughout this document.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119.
2.0 URL Scheme Name Registration Trees
In order to increase the efficiency and flexibility of the URL
scheme name registration process, the need is recognized for
multiple registration "trees". The registration requirements and
specific registration procedures for each tree differ, allowing the
overall registration procedure to accommodate the different natural
requirements for URL schemes. For example, a scheme that will be
recommended for wide support and implementation by the Internet
community requires a more complete review than a scheme intended to
be used for resources associated with proprietary software.
The first step in registering a new URL scheme name is to determine
which registration tree the scheme should be registered in.
Determination of the proper registration tree is based on the
intended use for the new scheme and the desired syntax for the
This document will discuss in detail the tree that reflects current
practice, under IETF ownership and control. It will also set forth
an outline to assist authors in creating new trees to address
differing needs for wide acceptance and interoperability, ease of
creation and use, and type and "strength" of ownership.
2.2 The IETF Tree
The IETF tree is intended for URL schemes of general interest to the
Internet community. The tree exists for URL schemes that require a
substantive review and approval process. It is expected that
applicability statements for particular applications will be
published from time to time that recommend implementation of, and
support for, URL schemes that have proven particularly useful in
2.3 Additional Registration Trees
From time to time and as required by the community, the IESG may
create new top-level registration trees. These trees may require
significant, little or no registration, and may allow change control
to rest in the hands of individuals or groups other than IETF. A
new tree should only be created if no existing tree can be shown to
address the set of needs of some sector of the community.
3.0 Requirements for Scheme Name Registration
3.1 General Requirements
All new URL schemes, regardless of registration tree, MUST conform
to the generic syntax for URLs as specified in RFC 2396.
3.2 The IETF Tree
Registration in the IETF tree requires publication of the URL scheme
syntax and semantics in either an Informational or Standards Track
RFC. In general, the creation of a new URL scheme requires a
Standards Track RFC. An Informational RFC may be employed for
registration only in the case of a URL scheme which is already in
wide usage and meets other standards set forth in [RFC-GUIDELINES],
such as "demonstrated utility" within the Internet Architecture; the
IESG shall have broad discretion in determining whether an
Informational RFC is suitable in any given case, and may either
recommend changes to such document prior to publication, or reject
it for publication. An Informational RFC purporting to describe a
URL scheme shall not be published without IESG approval. This is a
departure from practice for Informational RFCs as set forth in RFC
2026, for the purpose of ensuring that the registration of URL
schemes shall serve the best interests of the Internet community.
The NAMES of schemes registered in the IETF tree MUST NOT contain
the dash (also known as the hyphen and minus sign) character ('-')
USASCII value 2Dh. Use of this character can cause confusion with
schemes registered in alternative trees (see section 3.3).
An analysis of the security issues inherent in the new URL scheme
is REQUIRED. (This is in accordance with the basic requirements for
all IETF protocols.) URL schemes registered in the IETF tree should
not introduce additional security risks into the Internet Architec-
ture. For example, URLs should not embed information which should
remain confidential, such as passwords, nor should new schemes
subvert the security of existing schemes or protocols (i.e. by
layering or tunneling).
The "owner" of a URL scheme name registered in the IETF tree is
assumed to be the IETF itself. Modification or alteration of the
specification requires the same level of processing (e.g.
Informational or Standards Track RFC) as used for the initial
registration. Schemes originally defined via an Informational RFC
may, however, be replaced with Standards Track documents.
3.3 Alternative Trees
While public exposure and review of a URL scheme created in an
alternative tree is not required, using the IETF Internet-Draft
mechanism for peer review is strongly encouraged to improve the
quality of the specification. RFC publication of alternative tree
URL schemes is encouraged but not required. Material may be
published as an Informational RFC by sending it to the RFC Editor
(please follow the instructions to RFC authors, RFC 2223 ).
The defining document for an alternative tree may require public
exposure and/or review for schemes defined in that tree via a
mechanism other than the IETF Internet-Draft mechanism.
URL schemes created in an alternative tree must conform to the
generic URL syntax, RFC 2396. The tree's defining document may set
forth additional syntax and semantics requirements above and
beyond those specified in RFC 2396.
All new URL schemes SHOULD follow the Guidelines for URL Schemes,
set forth in RFC [URL-GUIDELINES] .
An analysis of the security issues inherent in the new URL scheme is
encouraged. Regardless of what security analysis is or is not
performed, all descriptions of security issues must be as accurate
as possible. In particular, a statement that there are "no security
issues associated with this scheme" must not be confused with "the
security issues associates with this scheme have not been assessed"
or "the security issues associated with this scheme cannot be
predicted because of <reason>".
There is absolutely no requirement that URL schemes created in an
alternative tree be secure or completely free from risks.
Nevertheless, the tree's defining document must set forth the
standard for security considerations, and in any event all known
security risks SHOULD be identified.
Change control must be defined for a new tree. Change control may
be vested in the IETF, or in an individual, group or other entity.
The change control standard for the tree must be approved by the
The syntax for alternative trees shall be as follows: each tree will
be identified by a unique prefix, which must be established in the
same fashion as a URL scheme name in the IETF tree, except that the
prefix must be defined by a Standards Track document. Scheme names
in the new tree are then constructed by prepending the prefix to an
identifier unique to each scheme in that tree, as prescribed by that
tree's identifying document:
For instance, the "foo" tree would allow creation of scheme names of
the form: "foo-blahblah:" and "foo-bar:", where the tree prescribes
an arbitrary USASCII string following the tree's unique prefix.
4.0 Registration Procedures
4.1 The IETF Tree
The first step in registering a new URL scheme in the IETF tree is
to publish an IETF Internet-Draft detailing the syntax and
semantics of the proposed scheme. The draft must, minimally,
address all of the items covered by the template provided in section
6 of this document.
After all issues raised during a review period of no less than 4
weeks have been addressed, submit the draft to the IESG for review.
The IESG will review the proposed new scheme and either refer the
scheme to a working group (existing or new) or directly present the
scheme to the IESG for a last call. In the former case, the working
group is responsible for submitting a final version of the draft to
the IESG for approval at such time as it has received adequate
review and deliberation.
4.2 Alternative Trees
Registration of URL schemes created in an alternative tree may be
formal, through IETF documents, IANA registration, or other
acknowledged organization; informal, through a mailing list or
other publication mechanism; or nonexistent. The registration
mechanism must be documented for each alternative tree, and must be
consistent for all URL scheme names created in that tree.
It is the responsibility of the creator of the tree's registration
requirements to establish that the registration mechanism is
workable as described; it is within the discretion of the IESG to
reject the document describing a tree if it determines the
registration mechanism is impractical or creates an undue burden on
a party who will not accept it. (For instance, if an IANA
registration mechanism is proposed, IESG might reject the tree if
its mechanism would create undue liability on the part of IANA.)
While the template in section 6 of this document is intended to
apply to URL scheme names in the IETF tree, it is also offered as a
guideline for those documenting alternative trees.
5.0 Change Control
5.1 Schemes in the IETF Tree
URL schemes created in the IETF tree are "owned" by the IETF itself
and may be changed, as needed, by updating the RFC that describes
them. Schemes described by Standards Track RFC but be replaced with
new Standards Track RFCs. Informational RFCs may be replaced by new
Informational RFCs or Standards Track RFCs.
5.2 Schemes in Alternative Trees
URL schemes in an alternative tree that are undocumented (as allowed
by that tree's rules) may be changed by their owner at any time
without notifying the IETF.
URL schemes created in an alternative tree that have been documented
by an Informational RFC, may be changed at any time by the owner,
however, an updated Informational RFC which details the changes
made, must be submitted to the IESG.
The owner of a URL scheme registered in an alternative tree and
documented by an Informational RFC may pass responsibility for the
registration to another person or agency by informing the IESG.
The IESG may reassign responsibility for a URL scheme registered in
an alternative tree and documented by an Informational RFC. The
most common case of this will be to enable changes to be made to
schemes where the scheme name is privately owned by the rules of its
tree, and the owner of the scheme name has died, moved out of
contact or is otherwise unable to make changes that are important to
The IESG may reclassify a URL scheme created in an alternative tree
and documented via an Informational RFC as "historic" if it
determines that the scheme is no longer in use.
6.0 Registration Template
The following issues should be addressed when documenting a new URL
URL scheme name.
URL scheme syntax. This should be expressed in a clear and
concise manner. The use of ABNF is encouraged. Please refer to
RFC [URL-GUIDELINES] for guidance on designing and explaining
your scheme's syntax.
Character encoding considerations. It is important to identify
what your scheme supports in this regard. It is obvious that for
interoperability, it is best if there is a means to support
character sets beyond USASCII, but especially for private
schemes, this may not be the case.
Intended usage. What sort of resource is being identified? If
this is not a 'resource' type of URL (e.g. mailto:), explain the
action that should be initiated by the consumer of the URL. If
there is a MIME type associated with this resource, please
Applications and/or protocols which use this URL scheme name.
Including references to documentation which defines the
applications and/or protocols cited is especially useful.
Interoperability considerations. If you are aware of any details
regarding your scheme which might impact interoperability, please
identify them here. For example: proprietary or uncommon
encoding method; inability to support multibyte character sets;
incompatibility with types or versions of underlying protocol
(if scheme is tunneled over another protocol).
Person & email address to contact for further information.
Applications and/or protocols which use this URL scheme name.
7.0 Security Considerations
Information that creates or updates a registration needs to be
Information concerning possible security vulnerabilities of a
protocol may change over time. Consequently, claims as to the
security properties of a registered URL scheme may change as well.
As new vulnerabilities are discovered, information about such
vulnerabilities may need to be attached to existing documentation,
so that users are not misled as to the true security properties of a
registered URL scheme.
If the IESG agrees to delegate the registration and change control
functions of an alternative tree to a group or individual outside of
the IETF, that group or individual should have sufficient security
procedures in place to authenticate registration changes.
 Berners-Lee, T., Fielding, R., Masinter, L., "Uniform Resource
Identifiers (URI): Generic Syntax", RFC 2396, August 1998
 Masinter, L., Alvestrand, H., Zigmond, D., Petke, R.,
"Guidelines for new URL Schemes", RFC [URL-GUIDELINES], August
 Postel, J., Reynolds, J., "Instructions to RFC Authors",
RFC 2223, October 1997.
9.0 Authors' Address
5000 Britton Road
P. O. Box 5000
Hilliard, OH 43026-5000
Phone: +1 614 723 4157
Fax: +1 614 723 8407
One Microsoft Way
Redmond, WA 98052-6399
Phone: +1 425-703-2293
FAX: +1 425-936-7329