Network Working Group M. Mealling

Network Working Group M. Mealling
Request for Comments: 5134 Refactored Networks, LLC
Category: Informational January 2008

A Uniform Resource Name Namespace for
the EPCglobal Electronic Product Code (EPC) and Related Standards

Status of This Memo

This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.

Abstract

This document describes URN namespaces that will identify various
objects within the EPCglobal system for identifying products within
ecommerce and supply chain management applications.

1. Introduction

The EPCglobal Architecture Framework [6] is a set of specifications
for reading, managing, and acting on object codes and other sensor
data as physical objects pass through a supply chain. Events and
metadata about physical objects are exchanged via EPCglobal
Electronic Product Code Information Services (EPCIS) that are
essentially web services that implement agreed upon schema and
interfaces.

Each object that is tracked by the EPCglobal Architecture Framework
is identified by one or more managed identifiers. In many cases,
these identification systems existed prior to the Internet becoming
widely used. One such namespace is the Global Trade Item Number, or
GTIN [7]. GTINs are widely used in global commerce and are managed
by GS1. In order for the EPCglobal Architecture Framework to
leverage the Internet to the fullest extent possible, the GTIN
namespace (and others, such as Global Location Numbers (GLNs),
Serialized Shipping Container Code (SSCC), etc. [7]) need to be
directly compatible with the URI family of identifiers.

The use of GTINs, GLNs, and SSCCs are all managed by GS1. Their use
within the EPCglobal Architecture Framework is managed by the GS1
subsidiary known as EPCglobal, Inc. For these, and possibly future

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RFC 5134 The EPC URN January 2008

identification systems, a single Uniform Resource Name (URN)
Namespace ID (NID) is being requested: 'epc'. Each of the identifier
namespaces mentioned will have a separate sub-space beneath the top
level 'epc' NID.

In addition to physical object identifiers, the EPCglobal
Architecture Framework requires new namespaces for naming system
components. In many cases, an interface within the EPCglobal
Architecture Framework is XML [11] based and as such will require
naming schemes for its XML schema [9] and various namespaces [10].
For these uses, another Uniform Resource Name (URN) Namespace ID
(NID) is being requested: 'epcglobal'. Each specification or system
component within the EPCglobal Architecture Framework will have a
separate sub-space beneath the top level 'epcglobal' NID.

Since the EPCglobal Architecture Framework is engineered for
widespread and general use, this namespace specification is a formal
one, and the namespace IDs that are being requested are 'epc' and
'epcglobal'. It is important to note that it is the explicit intent
that various sub-namespaces of the 'epc' NID actually name real,
physical objects and/or corporeal entities. In contrast, sub-
namespaces of the 'epcglobal' NID name logical or software
constructs, such as schema namespaces.

2. 'epc' Registration Template

Namespace ID:

"epc"

Registration Information:

Registration Version Number: 1
Registration Date: 2008-01-16

Declared registrant of the namespace:

EPCglobal, Inc. is a subsidiary of GS1
Princeton Pike Corporate Center
1009 Lenox Drive, Suite 202
Lawrenceville, NJ 08648, USA
[email protected]
Tel: +1-609-620-4585

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RFC 5134 The EPC URN January 2008

Declaration of structure:

The normative specification of the structure of the 'epc'
namespace is "EPC Tag Data Standards" [5]. The examples given
below are not normative.

The 'epc' namespace is a set of sub-namespaces that can be
extended in the future. The following ABNF [2] defines how the
sub-namespaces are identified and any restrictions on their
syntax (definitions not specified below can be found in RFC
2141 [1]):

EPC-URN = "urn:epc:" sub-ns-name ":" sub-ns
sub-ns-name = let-num [ 1*let-num-hyp ]
sub-ns = 1*<URN chars>
let-num = upper / lower / number
let-num-hyp = upper / lower / number / "-"
upper = %x41-5A ; "A" - "Z"
lower = %x61-7A ; "a" - "z"
number = "0" / "1" / "2" / "3" / "4" / "5" / "6" / "7" /
"8" / "9"

For example, the sub-namespace 'sgtin' has the following
definition (this ABNF is non-normative):

SGTIN-URI = "urn:epc:id:sgtin:" SGTINURIBody
SGTINURIBody = 2*(PaddedNumericComponent ".") NumericComponent
NumericComponent = ZeroComponent / NonZeroComponent
ZeroComponent = "0"
NonZeroComponent = NonZeroDigit *Digit
PaddedNumericComponent = *Digit
Digit = "0" / NonZeroDigit
NonZeroDigit = "1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9"

This equates to a namespace that has three period separated series of
digits:

urn:epc:id:sgtin:900100.0003456.1234567

The first series is a company prefix, the second denotes a product
reference assigned by that company, and the third is a serial number
for a specific instance of their product. Note that leading zeros
are significant.

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RFC 5134 The EPC URN January 2008

Relevant ancillary documentation:

The standards that define the EPCglobal Architecture Framework
and the processes for creating new sub-namespaces are managed
by EPCglobal, Inc. and can be found on its website. Several
sub-namespaces are defined in the "EPC Tag Data Standards" [5].

Identifier uniqueness considerations:

The namespaces that make up the 'epc' namespace are all managed
by an organization with almost 50 years of namespace management
experience. In all cases (existing or new), the uniqueness of
each namespace is an inherent part of the EPCglobal
Architecture Framework.

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.

Process of identifier assignment:

Names are assigned by the EPCglobal standards publication
process and by any entities that are sub-delegated by
EPCglobal. It is important to note that in many cases the
names assigned will explicitly denote physical objects and not
an electronic representation of that object.

Process of identifier resolution:

Certain sub-namespaces are resolved via the Object Naming
Service, defined in "Object Naming Service (ONS) Version 1.0"
[4], which is a valid implementation of the Dynamic Delegation
Discovery System that is defined in RFC 3401 [3].

Rules for Lexical Equivalence:

The entire URN is case-sensitive.

Conformance with URN Syntax:

There are no additional characters reserved except as noted in
the ABNF above.

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RFC 5134 The EPC URN January 2008

Validation mechanism:

In the case of each sub-namespace, there will be namespace-
specific rules for determining validity. In each case, the
reader is referred to the appropriate EPCglobal-maintained
documentation.

Scope:

Global

3. 'epcglobal' Registration Template

Namespace ID:

"epcglobal"

Registration Information:

Registration Version Number: 1
Registration Date: 2007-03-06

Declared registrant of the namespace:

EPCglobal, Inc. is a subsidiary of GS1
Princeton Pike Corporate Center
1009 Lenox Drive, Suite 202
Lawrenceville, NJ 08648, USA
[email protected]
Tel: +1-609-620-4585

Declaration of structure:

The normative specifications for the structure of the
'epcglobal' namespace are various standards available at
EPCglobal's public website. The examples given below are not
normative.

The 'epcglobal' namespace is a set of sub-namespaces that can
be extended in the future. The following ABNF defines how the
sub-namespaces are identified and any restrictions on their
syntax (definitions not specified below can be found in RFC
2141 [1]):

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RFC 5134 The EPC URN January 2008

EPCGLOBAL-URN = "urn:epcglobal:" subnsname ":" subns
subnsname = let-num [ 1*let-num-hyp ]
subns = 1*<URN chars>
let-num = upper / lower / number
let-num-hyp = upper / lower / number / "-"
upper = %x41-5A ; "A" - "Z"
lower = %x61-7A ; "a" - "z"
number = "0" / "1" / "2" / "3" / "4" / "5" / "6" / "7" /
"8" / "9"

For example, the identifier "urn:epcglobal:ale:xsd:1" is defined in
the "Application Level Events 1.0 Specification" [8] for use as an
XML namespace identifier for XML documents conforming to that
specification.

Relevant ancillary documentation:

The standards that define the EPCglobal Architecture Framework
and the processes for creating new sub-namespaces are managed
by EPCglobal, Inc. and can be found on its website.

Identifier uniqueness considerations:

The namespaces that make up the 'epcglobal' namespace are all
managed by an organization with almost 50 years of namespace
management experience. In all cases, the uniqueness of each
namespace is an inherent part of the EPCglobal Architecture
Framework.

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.

Process of identifier assignment:

Names are assigned by the EPCglobal, Inc. standards publication
process.

Process of identifier resolution:

No resolution mechanism is required or provided.

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RFC 5134 The EPC URN January 2008

Rules for Lexical Equivalence:

The entire URN is case-sensitive.

Conformance with URN Syntax:

There are no additional characters reserved except as noted in
the ABNF above.

Validation mechanism:

In the case of each sub-namespace, there will be namespace-
specific rules for determining validity. In each case, the
reader is referred to the appropriate EPCglobal-maintained
documentation.

Scope:

Global

4. IANA Considerations

This document includes two URN Namespace registrations that have been
entered into the IANA registry for URN NIDs.

5. Namespace Considerations

Due to EPCglobal, Inc. being a subsidiary of an internationally
recognized authority for the identifiers embedded within the 'epc'
namespace, as well as being the internationally recognized standards
body for the standards that define identifiers in the 'epcglobal'
namespace, these namespaces represent the best approach to naming
products and entities within the world of supply chain management and
ecommerce in general. There are no other alternative namespaces that
have the level of authority and industry acceptance that the EPC
does.

6. Community Considerations

The EPCglobal Architecture Framework is intended to bring the
Internet to the world of supply chain management and beyond. It can
be used to tie physical objects to their virtual descriptions and as
such has many wide ranging applications for the average Internet use.
Thus, it is very much the intent that this namespace, and the entire
EPCglobal Architecture Framework, considers the entire Internet as
the scope of its community.

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RFC 5134 The EPC URN January 2008

7. Security Considerations

The EPCglobal Architecture Framework is based almost exclusively on
Internet and Web standards. Thus, the security impacts of each of
its underlying technologies should be examined for weaknesses and
threats. The primary threats will come from the fact that these
names will identify physical things that can be of high value, thus
the temptation to spoof metadata about that identifier (its cost,
size, etc) will be much greater. Therefore, the role of digital
signatures, secure resolution mechanisms, and trust relationships is
very fundamental to the system.

8. References

8.1. Normative References

[1] Moats, R., "URN Syntax", RFC 2141, May 1997.

[2] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 4234, October 2005.

[3] Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part
One: The Comprehensive DDDS", RFC 3401, October 2002.

[4] EPCglobal, Inc., "EPCglobal Network Object Name Service (ONS)
1.0", August 2003.

[5] EPCglobal, Inc., "EPC(tm) Tag Data Standards Version 1.3",
February 2004.

[6] Traub, K., Allgair, G., Barthe, H., Burstein, L., Garrett, J.,
Hogan, B., Rodrigues, B., Sarma, S., Schmidt, J., Schramek, C.,
Stewart, R., and K. Suen, "The EPCglobal Architecture
Framework", July 2005.

[7] GS1, "GS1 General Specifications v7.1", January 2007.

[8] EPCglobal, Inc., "The Application Level Events (ALE)
Specification, Version 1.0", September 2005.

8.2. Informative References

[9] Thompson, H., Maloney, M., Beech, D., and N. Mendelsohn, "XML
Schema Part 1: Structures Second Edition", World Wide Web
Consortium Recommendation REC-xmlschema-1-20041028,
October 2004,
<http://www.w3.org/TR/2004/REC-xmlschema-1-20041028>.

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RFC 5134 The EPC URN January 2008

[10] Layman, A., Tobin, R., Bray, T., and D. Hollander, "Namespaces
in XML 1.1", World Wide Web Consortium FirstEdition REC-xml-
names11-20040204, February 2004,
<http://www.w3.org/TR/2004/REC-xml-names11-20040204>.

[11] Bray, T., Maler, E., Yergeau, F., Sperberg-McQueen, C., and J.
Paoli, "Extensible Markup Language (XML) 1.0 (Third Edition)",
World Wide Web Consortium FirstEdition REC-xml-20040204,
February 2004, <http://www.w3.org/TR/2004/REC-xml-20040204>.

Author's Address

Michael Mealling
Refactored Networks, LLC
1635 Old Hwy 41
Suite 112, Box 138
Kennesaw, GA 30152
US

Phone: +1 678 581 9656
EMail: [email protected]
URI: http://www.refactored-networks.com

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RFC 5134 The EPC URN January 2008

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