A URN Namespace for ucode
A name format for identifying real-world objects with tags.
Ishikawa, C., "A URN Namespace for ucode", RFC 6588, DOI 10.17487/RFC6588, April 2012, <https://www.rfc-editor.org/info/rfc6588>.
@misc{rfc6588,
series = {Request for Comments},
number = 6588,
howpublished = {RFC 6588},
publisher = {RFC Editor},
doi = {10.17487/RFC6588},
url = {https://www.rfc-editor.org/info/rfc6588},
author = {C. Ishikawa},
title = {{A URN Namespace for ucode}},
pagetotal = 8,
year = 2012,
month = apr,
} RFC text
Contents
Internet Engineering Task Force (IETF) C. Ishikawa
Request for Comments: 6588 YRP Ubiquitous Networking Lab
Category: Informational April 2012
ISSN: 2070-1721
A URN Namespace for ucode
Abstract
This document describes a Uniform Resource Name (URN) namespace for
ucode, an identifier system for objects and places. ucode technology
is used in many applications, and this document provides a URN
namespace for ucode to enable its use in Internet-related devices and
software.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6588.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
1. Introduction
ucode [UCODE] is an identifier to be stored in many types of tags
(not limited to Radio Frequency Identification (RFID) tags). Its
allocation and management is handled by the Ubiquitous ID Center
[UIDC]. The embedding of ucode in many types of tags (RFID tags,
optical code, infrared markers, and even sound source) is also
specified by the Ubiquitous ID Center.
The basic length of ucode is 128 bits, but it is extensible in units
of 128 bits if necessary.
ucode has been devised to identify objects and places where existing
standards do not fit the application needs or the scope of the
applications or where the allocation policy of existing standards is
too limited for Small and Medium Enterprises (SMEs), small-scale
research laboratories at academic institutions, or individual users.
Applications that use ucode take advantage of the Internet
extensively. Use of ucode is open to anybody. Those who wish to
have ucode allocated can do so either by having ucode subspace
allocated to them directly from the Ubiquitous ID Center [UIDC] or by
obtaining tags that have pre-stored ucode from so called "providers"
[UCDMIP]. Such tags are certified as ucode tags [UIDTAG], and the
reader specifications are published so that there will be many
readers available for such tags.
By having a URN for ucode, we can facilitate the use of ucode in many
Internet-related devices and software for the benefit of existing and
future users of ucode and people who will access such tags attached
to objects and places. Since an application based on ucode can run
across organizational boundaries and spread across regions and
countries, a formal URN Namespace Identifier (NID) assignment for
'ucode' is requested.
2. 'ucode' Registration Template
Namespace ID:
'ucode' requested
Registration Information:
Registration Version Number: 1
Registration Date: 2011-12-21
Declared registrant of the namespace:
T-Engine Forum
2-20-1, Nishi-Gotanda
Shinagawa, Tokyo, 141-0031
Japan
office@t-engine.org
Tel: +81-3-5437-0572
Declaration of syntactic structure:
The structure of the namespace for 'ucode' using the hexadecimal
representation of the identifier is as follows using ABNF [RFC5234].
UCODE-URN = "urn:ucode:" ucode-name
ucode-name = "_" ucode-number
ucode-number = 1*ucode-value
ucode-value = 32HEXDIG
HEXDIG = DIGIT / "A" / "B" / "C" / "D" / "E" / "F"
DIGIT = %x30-39
; 0-9
NOTE 1: "1*" at the start of the ucode-number definition is not a
typo. Although the currently used ucode [UCODE] is 128 bits (16
octets), thus requiring 32 hexadecimal characters to represent
serially, ucode is designed to be extensible in increments of 128
bits. So, in the distant future, we may need to repeat the chunks of
128 bits. This is why "1*" precedes ucode-value.
NOTE 2: ucode-name starts with a "_" because it is also intended to
be used as an identifier for XML [W3CXML]. Because an XML tag can't
start with a digit, an "_" (underscore) is inserted at the beginning
to make sure ucode-name starts with a non-digit. For example, the
128-bit ucode value 0123456789ABCDEF0123456789ABCDEF, expressed in a
series of hexadecimal digits, is as follows:
urn:ucode:_0123456789ABCDEF0123456789ABCDEF
Relevant ancillary documentation:
ucode, the identifier expressed by ucode-number, is managed by the
Ubiquitous ID Center [UIDC], which is a sub-organization of the
T-Engine Forum [TEF]. The document "Ubiquitous Code: ucode" [UCODE]
defines this identifier system.
Identifier uniqueness considerations:
The 'ucode' namespace is managed by the Ubiquitous ID Center. The
Ubiquitous ID Center assigns the identifier, ucode, in such a way
that the uniqueness of the 'ucode' namespace will be maintained.
Identifier persistence considerations:
The assignment process guarantees that names are not reassigned and
that the binding between the name and its resource is permanent,
regardless of any standards or organizational changes or the
assignment period.
Process of identifier assignment:
Names are assigned by the Ubiquitous ID Center and by any entities
that are sub-delegated by the Ubiquitous ID Center. This assignment
process is based on "ucode Management Implementing Procedures"
[UCDMIP] established by the Ubiquitous ID Center.
Process of identifier resolution:
The process of identifier resolution is currently based on the "ucode
Resolution Protocol" [UCSURP]. It will be enhanced by using newer
recommendations from ITU-T and/or standards from ISO.
Rules for lexical equivalence:
The entire UCODE-URN is case-sensitive.
NOTE: This is an additional restriction imposed on the ucode
namespace by the requirements of some major applications of ucode in
existence. Only capital "A", "B", "C", ..., "F" are allowed as part
of hexadecimal characters.
Conformance with URN syntax:
There are no special reserved characters. The URN of this namespace
conforms to RFC 2141 [RFC2141] and RFC 3986 [RFC3986].
Validation mechanism:
No special considerations.
Scope:
Global.
3. IANA Considerations
One URN Namespace registration for 'ucode' (46) has been entered
into the IANA "Formal URN Namespaces" sub-registry for URN NIDs.
4. Namespace Considerations
ucode, the identifier expressed by ucode-number, is a unique
identification number to identify a tangible object or a place.
Additionally, ucode can be assigned to "content" or "information"
that does not exist in the real world or a "concept" that is yet more
abstract.
ucode has been devised to identify objects and places where existing
standards do not fit the application needs or the scope of the
applications or where the allocation policy of existing standards is
too limited for SMEs, small-scale research laboratories at academic
institutions, or individual users.
ucode is only an identification number, and its value (or its sub-
bitfields) does not contain any pre-assigned meaning. Any relevant
information about the object or place to which a ucode is assigned is
stored in a data server that can be reached after a "resolution
process" [UCSURP]. This resolution process usually occurs over the
Internet.
ucode can be assigned to an object to be identified regardless of the
type of application. ucode is expected to be stored in any kind of
tags (2D optical code, RFID, etc.), and it provides a framework where
anyone can obtain unique numbers for identification purposes.
ucode has been designed to provide the services outlined in ITU-T
Recommendation F.771 [ITU-T-F771] and to operate in the framework of
ITU-T Recommendation H.621 [ITU-T-H621].
ucode architecture is general enough to cover many applications for
the users.
5. Community Considerations
This namespace enables ucode to be stored in tags that are designed
to store URN. Also, ucode-related information can be described as
metadata using the URN namespace. Thus, the namespace facilitates
the exchange of descriptions regarding objects and places among
multiple organizations.
It is expected that many small-scale providers will offer ucode tags
to small users and that large scale providers will hand out millions
of tags to users.
The resolution servers and applications will be available to general
users with appropriate access control over the Internet. The
published specification for resolver and access services for 'ucode'
allows the creation of client software for many types of computers
including small mobile terminals and ever-popular smartphones.
6. Security Considerations
There are no additional security considerations other than those
normally associated with the use and resolution of URNs in general.
7. References
7.1. Normative References
[UCODE] T-Engine Forum, Ubiquitous ID Center, "ucode: Ubiquitous
Code", UID-00010,
<http://www.uidcenter.org/spec#UID-00010>.
[UCDMIP] T-Engine Forum, Ubiquitous ID Center, "ucode Management
Implementing Procedures", UID-00034,
<http://www.uidcenter.org/spec#UID-00034>.
[UCSURP] T-Engine Forum, Ubiquitous ID Center, "Simplified ucode
Resolution Protocol", UID-00005,
<http://www.uidcenter.org/spec#UID-00005>.
[UIDTAG] T-Engine Forum, Ubiquitous ID Center, "ucode Tag
Architecture", UID-00017,
<http://www.uidcenter.org/spec#UID-00017>.
[RFC2141] Moats, R., "URN Syntax", RFC 2141, May 1997.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, RFC
3986, January 2005.
[RFC5234] Crocker, D., Ed., and P. Overell, "Augmented BNF for
Syntax Specifications: ABNF", STD 68, RFC 5234, January
2008.
[ITU-T-F771] ITU-T, "Service description and requirements for
multimedia information access triggered by tag-based
identification", ITU-T Recommendation F.771,
<http://www.itu.int/rec/T-REC-F.771-200808-I>.
[ITU-T-H621] ITU-T, "Architecture of a system for multimedia
information access triggered by tag-based
identification", ITU-T Recommendation H.621,
<http://www.itu.int/rec/T-REC-H.621-200808-I>.
7.2 Informative References
[W3CXML] W3C, "Extensible Markup Language (XML) 1.1",
<http://www.w3.org/TR/xml11/>.
[UIDC] Ubiquitous ID Center, <http://www.uidcenter.org/>.
[TEF] T-Engine Forum, <http://www.t-engine.org/>.
8. Acknowledgments
The author would like to thank Peter Saint-Andre, the Document
Shepherd/Responsible Area Director for this document, for providing
valuable suggestions. The author would also like to thank the
following people who helped to improve this document:
Adrian Farrel
David Harrington
Pete Resnick
Stephen Farrel
Ted Hardie
Wesley Eddy
The author would also like to thank the members of T-Engine Forum who
have built prototype and real-world applications using ucode and
offered valuable feedback. Application examples from these members
can be found on the Ubiquitous ID Center web site [UIDC] and on
www.youtube.com (search for "uidcenter" without the quotes).
9. Contributors
Ken Sakamura
Noboru Koshizuka
Katsunori Shindo
Tomonori Usaka
Past and current members of the uID architecture group at the
University of Tokyo and the YRP Ubiquitous Networking Laboratory (YRP
UNL)
Author's Address
Chiaki Ishikawa
YRP Ubiquitous Networking Laboratory
2-20-1, Nishi-Gotanda
Shinagawa, Tokyo, 141-0031
Japan
Tel: +81-3-5437-2270
FAX: +81-3-5437-2271
EMail: chiaki.ishikawa@ubin.jp
AI ELI5
On this page
§1What is ucode?
ucode is a 128-bit identifier system for objects and places, managed by the Ubiquitous ID Center, a sub-organization of Japan's T-Engine Forum. The identifier was created to fill a gap where existing identifier standards did not fit application needs or had allocation policies that were too restrictive for small and medium enterprises (SMEs), academic research labs, or individual users. The basic ucode length is 128 bits (16 bytes, or 32 hexadecimal digits), and it is extensible in 128-bit increments if longer identifiers are needed. ucode can be embedded in many types of tags: RFID tags, 2D optical codes, infrared markers, and even sound sources. Unlike identifiers that encode meaning in their bit structure, ucode is opaque—any relevant information about the object is stored separately on a resolution server reachable over the Internet. Applications using ucode take advantage of Internet connectivity; for example, a smartphone can scan a QR code containing ucode, query a server to retrieve information about the object, and display it to the user. The ucode system was designed to be compatible with ITU-T Recommendation F.771 (multimedia information access triggered by tag-based identification) and ITU-T Recommendation H.621 (architecture for such systems).
ucode is a number you can put on a physical thing—a tag on a product, a label on a place. Anybody can get numbers, unlike expensive barcodes. Software looks up the number on the internet to find information about the thing.
§2The URN Namespace and Syntax
A URN (Uniform Resource Name) is a persistent identifier that can be used on the Internet, similar to a URL but not bound to a physical location. The RFC registers ucode as a formal URN Namespace Identifier (NID), enabling ucode to be used in the format urn:ucode:identifier. The syntax is defined in ABNF (Augmented Backus-Naur Form) as: ucode URNs take the form urn:ucode:_ followed by one or more 32-character hexadecimal strings (for future extensibility beyond the current 128 bits). For example, a 128-bit ucode with the hexadecimal value 0123456789ABCDEF0123456789ABCDEF is written as urn:ucode:_0123456789ABCDEF0123456789ABCDEF. The underscore prefix is required to make the identifier compatible with XML tag naming rules, which do not allow tags to start with a digit. The entire URN is case-sensitive, and only capital letters A through F are allowed in hexadecimal digits, not lowercase. The namespace conforms to RFC 2141 (URN Syntax) and RFC 3986 (URI Generic Syntax).
A ucode URN is like a web address for a physical object. It always starts with urn:ucode: followed by the 32-digit code. The underscore at the start lets it work with XML.
§3How ucode is Managed and Resolved
The Ubiquitous ID Center maintains the ucode namespace and assigns identifiers in a way that guarantees uniqueness. Uniqueness is assured because all identifiers are assigned from a single registry managed by the Center. Identifiers are never reassigned, and the binding between a ucode and its assigned owner is permanent, regardless of organizational changes or assignment periods. Subspace allocation and delegation are possible: the Ubiquitous ID Center can sub-delegate assignment authority to other organizations. All assignment follows the ucode Management Implementing Procedures (UCDMIP) established by the Center. Identifier resolution—looking up what a ucode refers to—is currently handled by the ucode Resolution Protocol (UCSURP), which is published by the Center. The RFC notes that the resolution process will be enhanced using newer recommendations from ITU-T and standards from ISO in the future. Applications that encounter a ucode URN can use standard URN resolution mechanisms to query a resolver server and obtain metadata about the object or place the ucode identifies.
The Ubiquitous ID Center keeps the master list of codes and makes sure each one is unique. When a program finds a code, it can ask a server 'what is this code for?' and get back information about the thing.
§4Benefits for Small Organizations and Communities
The URN namespace registration enables ucode to be used in Internet protocols and software for the first time. Before this RFC, ucode was managed outside the IETF framework and could not be formally referenced in Internet specifications. With a registered URN namespace, ucode can be stored directly in tags designed to store URNs, metadata about objects can be exchanged using standard formats, and application developers can build ucode support into widespread platforms. The RFC emphasizes that this is particularly beneficial for small-scale providers, SMEs, academic research labs, and individual users who would otherwise have to use existing identifier systems that require expensive licensing or membership fees. Because ucode assignment is open to anyone who applies to the Ubiquitous ID Center or purchases pre-assigned tags from certified providers, the system provides an alternative to closed identifier systems. Applications can now be developed by client software for many types of devices, including smartphones and mobile terminals. The RFC also notes that the resolution servers and applications will be available to general users with appropriate access control, enabling widespread adoption.
Small groups and individuals can now use ucode like big companies use barcodes. The internet recognizes it as a real identifier system. This is cheaper and more flexible than traditional bar codes.