Internet DRAFT - draft-arkko-core-dev-urn
draft-arkko-core-dev-urn
Network Working Group J. Arkko
Internet-Draft Ericsson
Intended status: Informational C. Jennings
Expires: May 3, 2018 Cisco
Z. Shelby
Sensinode
October 30, 2017
Uniform Resource Names for Device Identifiers
draft-arkko-core-dev-urn-05
Abstract
This memo describes a new Uniform Resource Name (URN) namespace for
hardware device identifiers. A general representation of device
identity can be useful in many applications, such as in sensor data
streams and storage, or equipment inventories. A URN-based
representation can be easily passed along in any application that
needs the information.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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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."
This Internet-Draft will expire on May 3, 2018.
Copyright Notice
Copyright (c) 2017 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
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publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements language . . . . . . . . . . . . . . . . . . . . 3
3. DEV URN Definition . . . . . . . . . . . . . . . . . . . . . 3
4. DEV URN Subtypes . . . . . . . . . . . . . . . . . . . . . . 5
4.1. MAC Addresses . . . . . . . . . . . . . . . . . . . . . . 5
4.2. 1-Wire Device Identifiers . . . . . . . . . . . . . . . . 6
4.3. Organization-Defined Identifiers . . . . . . . . . . . . 6
5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
8.1. Normative References . . . . . . . . . . . . . . . . . . 8
8.2. Informative References . . . . . . . . . . . . . . . . . 9
Appendix A. Changes from Previous Version . . . . . . . . . . . 11
Appendix B. Acknowledgments . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
This memo describes a new Uniform Resource Name (URN) [RFC2141]
[RFC3406] namespace for hardware device identifiers. A general
representation of device identity can be useful in many applications,
such as in sensor data streams and storage, or equipment inventories
[RFC7252], [I-D.ietf-core-senml]. A URN-based representation can be
easily passed along in any application that needs the information, as
it fits in protocols mechanisms that are designed to carry URNs
[RFC2616], [RFC3261], [RFC7252]. Finally, URNs can also be easily
carried and stored in formats such as XML [W3C.REC-xml-19980210] or
JSON [I-D.ietf-core-senml] [RFC4627]. Using URNs in these formats is
often preferable as they are universally recognized, self-describing,
and therefore avoid the need for agreeing to interpret an octet
string as a specific form of a MAC address, for instance.
This memo defines identity URN types for situations where no such
convenient type already exist. For instance, [RFC6920] defines
cryptographic identifiers, [RFC7254] defines International Mobile
station Equipment Identity (IMEI) identifiers for use with 3GPP
cellular systems, and [I-D.atarius-dispatch-meid-urn] defines Mobile
Equipment Identity (MEID) identifiers for use with 3GPP2 cellular
systems. Those URN types should be employed when such identities are
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transported; this memo does not redefine these identifiers in any
way.
Universally Unique IDentifier (UUID) URNs [RFC4122] are another
alternative way for representing device identifiers, and already
support MAC addresses as one of type of an identifier. However,
UUIDs can be inconvenient in environments where it is important that
the identifiers are as simple as possible and where additional
requirements on stable storage, real-time clocks, and identifier
length can be prohibitive. UUID-based identifiers are recommended
for all general purpose uses when MAC addresses are available as
identifiers. The device URN defined in this memo is recommended for
constrained environments.
Future device identifier types can extend the device device URN type
defined here, or define their own URNs.
Note that long-term stable unique identifiers are problematic for
privacy reasons and should be used with care or avoided as described
in [RFC7721].
The rest of this memo is organized as follows. Section 3 defines the
"DEV" URN type, and Section 4 defines subtypes for IEEE MAC-48,
EUI-48 and EUI-64 addresses and 1-wire device identifiers. Section 5
gives examples. Section 6 discusses the security considerations of
the new URN type. Finally, Section 7 specifies the IANA registration
for the new URN type and sets requirements for subtype allocations
within this type.
2. Requirements language
In this document, the key words "MAY", "MUST, "MUST NOT", "OPTIONAL",
"RECOMMENDED", "SHOULD", and "SHOULD NOT", are to be interpreted as
described in [RFC2119].
3. DEV URN Definition
Namespace ID: "dev" requested
Registration Information: This is the first registration of this
namespace, 2011-08-27.
Registration version number: 1
Registration date: 2011-08-27
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Declared registrant of the namespace: IETF and the CORE working
group. Should the working group cease to exist, discussion should be
directed to the general IETF discussion forums or the IESG.
Declaration of syntactic structure: The identifier is expressed in
ASCII (UTF-8) characters and has a hierarchical structure as follows:
devurn = "urn:dev:" body componentpart
body = macbody / owbody / orgbody / otherbody
macbody = "mac:" hexstring
owbody = "ow:" hexstring
orgbody = "dn:" number ":" identifier
otherbody = subtype ":" identifier
subtype = ALPHA *(DIGIT / ALPHA)
identifier = 1*unreservednout
unreservednout = ALPHA / DIGIT / "-" / "."
componentpart = [ "_" component [ componentpart ]]
component = *1(DIGIT / ALPHA)
hexstring = hexbyte /
hexbyte hexstring
hexbyte = hexdigit hexdigit
hexdigit = DIGIT / hexletter
hexletter = "a" / "b" / "c" / "d" / "e" / "f"
number = *1DIGIT
The above Augmented Backus-Naur Form (ABNF) uses the DIGIT and ALPHA
rules defined in [RFC5234], which are not repeated here. The rule
for unreserved is defined in Section 2.3 of [RFC3986].
The device identity namespace includes three subtypes, and more may
be defined in the future as specified in Section 7.
The optional components following the hexstring are strings depicting
individual aspects of a device. The specific strings and their
semantics are up to the designers of the device, but could be used to
refer to specific interfaces or functions within the device.
Relevant ancillary documentation: See Section 4.
Identifier uniqueness considerations: Device identifiers are
generally expected to be unique, barring the accidental issue of
multiple devices with the same identifiers.
Identifier persistence considerations: This URN type SHOULD only be
used for persistent identifiers, such as hardware-based identifiers
or cryptographic identifiers based on keys intended for long-term
usage.
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Process of identifier assignment: The process for identifier
assignment is dependent on the used subtype, and documented in the
specific subsection under Section 4.
Process for identifier resolution: The device identities are not
expected to be globally resolvable. No identity resolution system is
expected. Systems may perform local matching of identities to
previously seen identities or configured information, however.
Rules for Lexical Equivalence: The lexical equivalence of the DEV URN
is defined as an exact and case sensitive string match. Note that
the two subtypes defined in this document use only lower case
letters, however. Future types might use identifiers that require
other encodings that require a more full-blown character set (such as
BASE64), however.
Conformance with URN Syntax: The string representation of the device
identity URN and of the MEID sub namespace is fully compatible with
the URN syntax.
Validation Mechanism: Specific subtypes may be validated through
mechanisms discussed in Section 4.
Scope: DEV URN is global in scope.
4. DEV URN Subtypes
4.1. MAC Addresses
DEV URNs of the "mac" subtype are based on the EUI-64 identifier
[IEEE.EUI64] derived from a device with a built-in 64-bit EUI-64.
The EUI-64 is formed from 24 or 36 bits of organization identifier
followed by 40 or 28 bits of device-specific extension identifier
assigned by that organization.
In the DEV URN "mac" subtype the hexstring is simply the full EUI-64
identifier represented as a hexadecimal string. It is always exactly
16 characters long.
MAC-48 and EUI-48 identifiers are also supported by the same DEV URN
subtype. To convert a MAC-48 address to an EUI-64 identifier, The
OUI of the Ethernet address (the first three octets) becomes the
organization identifier of the EUI-64 (the first three octets). The
fourth and fifth octets of the EUI are set to the fixed value FFFF
hexadecimal. The last three octets of the Ethernet address become
the last three octets of the EUI-64. The same process is used to
convert an EUI-48 identifier, but the fixed value FFFE is used
instead.
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Identifier assignment for all of these identifiers rests within the
IEEE.
4.2. 1-Wire Device Identifiers
The 1-Wire* system is a device communications bus system designed by
Dallas Semiconductor Corporation. 1-Wire devices are identified by a
64-bit identifier that consists of 8 byte family code, 48 bit
identifier unique within a family, and 8 bit CRC code [OW].
*) 1-Wire is a registered trademark.
In DEV URNs with the "ow" subtype the hexstring is a representation
of the full 64 bit identifier as a hexadecimal string. It is always
exactly 16 characters long. Note that the last two characters
represent the 8-bit CRC code. Implementations MAY check the validity
of this code.
Family code and identifier assignment for all 1-wire devices rests
with the manufacturers.
4.3. Organization-Defined Identifiers
Device identifiers that have only a meaning within an organisation
can also be used to represent vendor-specific or experimental
identifiers or identifiers designed for use within the context of an
organisation. Organisations are identified by the Private Enterprise
Number [RFC2578].
5. Examples
The following three examples provide examples of MAC-based, 1-Wire,
and Cryptographic identifiers:
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urn:dev:mac:0024befffe804ff1 # The MAC address of
# Jari's laptop
urn:dev:ow:10e2073a01080063 # The 1-Wire temperature
# sensor in Jari's
# kitchen
urn:dev:ow:264437f5000000ed_humidity # The laundry sensor's
# humidity part
urn:dev:ow:264437f5000000ed_temperature # The laundry sensor's
# temperature part
urn:dev:org:32473:123456 # Device 123456 in
# the RFC 5612 example
# organisation
6. Security Considerations
On most devices, the user can display device identifiers. Depending
on circumstances, device identifiers may or may not be modified or
tampered by the user. An implementation of the DEV URN MUST NOT
change these properties from what they were intended. In particular,
a device identifier that is intended to be immutable should not
become mutable as a part of implementing the DEV URN type. More
generally, nothing in this memo should be construed to override what
the relevant device specifications have already said about the
identifiers.
Other devices in the same network may or may not be able to identify
the device. For instance, on Ethernet network, the MAC address of a
device is visible to all other devices.
The URNs generated according to the rules defined in this document
result in long-term stable unique identifiers for the devices. Such
identifiers may have privacy and security implications because they
may enable correlating information about a specific device over a
long period of time, location tracking, and device specific
vulnerability exploitation [RFC7721]. Also, usually there is no easy
way to change the identifier. Therefore these identifiers need to be
used with care and especially care should be taken avoid leaking them
outside of the system that is intended to use the identifiers.
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7. IANA Considerations
This document requests the registration of a new URN namespace for
"DEV", as described in Section 3.
Additional subtypes for DEV URNs can be defined through IETF Review
or IESG Approval [RFC5226].
Such allocations are appropriate when there is a new namespace of
some type of device identifiers, defined in stable fashion and with a
publicly available specification that can be pointed to.
Note that the organisation (Section 4.3) device identifiers can also
be used in some cases, at least as a temporary measure. It is
preferrable, however, that long-term usage of a broadly employed
device identifier be registered with IETF rather than used through
the organisation device identifier type.
8. References
8.1. Normative References
[IEEE.EUI64]
IEEE, "Guidelines For 64-bit Global Identifier (EUI-64)",
IEEE , unknown year,
<http://standards.ieee.org/db/oui/tutorials/EUI64.html>.
[OW] IEEE, "Overview of 1-Wire(R) Technology and Its Use",
MAXIM
http://www.maxim-ic.com/app-notes/index.mvp/id/1796, June
2008,
<http://www.maxim-ic.com/app-notes/index.mvp/id/1796>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2141] Moats, R., "URN Syntax", RFC 2141, DOI 10.17487/RFC2141,
May 1997, <https://www.rfc-editor.org/info/rfc2141>.
[RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J.
Schoenwaelder, Ed., "Structure of Management Information
Version 2 (SMIv2)", STD 58, RFC 2578,
DOI 10.17487/RFC2578, April 1999,
<https://www.rfc-editor.org/info/rfc2578>.
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[RFC3406] Daigle, L., van Gulik, D., Iannella, R., and P. Faltstrom,
"Uniform Resource Names (URN) Namespace Definition
Mechanisms", RFC 3406, DOI 10.17487/RFC3406, October 2002,
<https://www.rfc-editor.org/info/rfc3406>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<https://www.rfc-editor.org/info/rfc5226>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>.
8.2. Informative References
[I-D.atarius-dispatch-meid-urn]
Atarius, R., "A Uniform Resource Name Namespace for the
Device Identity and the Mobile Equipment Identity (MEID)",
draft-atarius-dispatch-meid-urn-13 (work in progress),
October 2017.
[I-D.ietf-core-senml]
Jennings, C., Shelby, Z., Arkko, J., Keranen, A., and C.
Bormann, "Media Types for Sensor Measurement Lists
(SenML)", draft-ietf-core-senml-10 (work in progress),
July 2017.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616,
DOI 10.17487/RFC2616, June 1999,
<https://www.rfc-editor.org/info/rfc2616>.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261,
DOI 10.17487/RFC3261, June 2002,
<https://www.rfc-editor.org/info/rfc3261>.
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[RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander,
"SEcure Neighbor Discovery (SEND)", RFC 3971,
DOI 10.17487/RFC3971, March 2005,
<https://www.rfc-editor.org/info/rfc3971>.
[RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)",
RFC 3972, DOI 10.17487/RFC3972, March 2005,
<https://www.rfc-editor.org/info/rfc3972>.
[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122,
DOI 10.17487/RFC4122, July 2005,
<https://www.rfc-editor.org/info/rfc4122>.
[RFC4627] Crockford, D., "The application/json Media Type for
JavaScript Object Notation (JSON)", RFC 4627,
DOI 10.17487/RFC4627, July 2006,
<https://www.rfc-editor.org/info/rfc4627>.
[RFC5612] Eronen, P. and D. Harrington, "Enterprise Number for
Documentation Use", RFC 5612, DOI 10.17487/RFC5612, August
2009, <https://www.rfc-editor.org/info/rfc5612>.
[RFC6920] Farrell, S., Kutscher, D., Dannewitz, C., Ohlman, B.,
Keranen, A., and P. Hallam-Baker, "Naming Things with
Hashes", RFC 6920, DOI 10.17487/RFC6920, April 2013,
<https://www.rfc-editor.org/info/rfc6920>.
[RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252,
DOI 10.17487/RFC7252, June 2014,
<https://www.rfc-editor.org/info/rfc7252>.
[RFC7254] Montemurro, M., Ed., Allen, A., McDonald, D., and P.
Gosden, "A Uniform Resource Name Namespace for the Global
System for Mobile Communications Association (GSMA) and
the International Mobile station Equipment Identity
(IMEI)", RFC 7254, DOI 10.17487/RFC7254, May 2014,
<https://www.rfc-editor.org/info/rfc7254>.
[RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy
Considerations for IPv6 Address Generation Mechanisms",
RFC 7721, DOI 10.17487/RFC7721, March 2016,
<https://www.rfc-editor.org/info/rfc7721>.
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[W3C.REC-xml-19980210]
Sperberg-McQueen, C., Bray, T., and J. Paoli, "XML 1.0
Recommendation", World Wide Web Consortium FirstEdition
REC-xml-19980210, February 1998,
<http://www.w3.org/TR/1998/REC-xml-19980210>.
Appendix A. Changes from Previous Version
Version -05 made a change to the delimiter for parameters within a
DEV URN. Given discussions on allowed character sets in SenML
[I-D.ietf-core-senml], we would like to suggest that the "_"
character be used instead of ";", to avoid the need to translate DEV
URNs in SenML-formatted communications or files. However, this
reverses the earlier decision to not use unreserved characters. This
also means that device IDs cannot use "_" characters, and have to
employ other characters instead. Feedback on this decision is
sought.
Version -05 also introduced local or organisation-specific device
identifiers. Organisations are identified by their PEN number
(although we considered FQDNs as a potential alternative. The
authors belive an organisation-specific device identifier type will
make experiments and local use easier, but feedback on this point and
the choice of PEN numbers vs. other possible organisation identifiers
would be very welcome.
Version -05 also added some discussion of privacy concerns around
long-term stable identifiers.
Finally, version -05 clarified the situations when new allocations
within the registry of possible device identifier subtypes is
appropriate.
Version -04 is a refresh, as the need and interest for this
specification has re-emerged. And the editing author has emerged
back to actual engineering from the depths of IETF administration.
Version -02 introduced several changes. The biggest change is that
with the NI URNs [RFC6920], it was no longer necessary to define
cryptographic identifiers in this specification. Another change was
that we incorporated a more generic syntax for future extensions;
non-hexstring identifiers can now also be supported, if some future
device identifiers for some reason would, for instance, use BASE64.
As a part of this change, we also changed the component part
separator character from '-' to ';' so that the general format of the
rest of the URN can employ the unreserved characters [RFC3986].
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Appendix B. Acknowledgments
The authors would like to thank Ari Keranen, Stephen Farrell,
Christer Holmberg, Peter Saint-Andre, Wouter Cloetens, and Ahmad
Muhanna for interesting discussions in this problem space. We would
also like to note prior documents that focused on specific device
identifiers, such as [RFC7254] or [I-D.atarius-dispatch-meid-urn].
Authors' Addresses
Jari Arkko
Ericsson
Jorvas 02420
Finland
Email: jari.arkko@piuha.net
Cullen Jennings
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA
Phone: +1 408 421-9990
Email: fluffy@cisco.com
Zach Shelby
Sensinode
Kidekuja 2
Vuokatti 88600
FINLAND
Phone: +358407796297
Email: zach@sensinode.com
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