Network Working Group                                 M. Montemurro, Ed.
Internet-Draft                                                  A. Allen
Intended status: Informational                  Research in Motion (RIM)
Expires: October 2, 2009                                     D. McDonald
                                                            unaffiliated
                                                               P. Gosden
                                                         GSM Association
                                                          March 31, 2009


A Uniform Resource Name Namespace For The GSM Association (GSMA) and the
         International Mobile station Equipment Identity(IMEI)
                   draft-montemurro-gsma-imei-urn-04

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.  This document may contain material
   from IETF Documents or IETF Contributions published or made publicly
   available before November 10, 2008.  The person(s) controlling the
   copyright in some of this material may not have granted the IETF
   Trust the right to allow modifications of such material outside the
   IETF Standards Process.  Without obtaining an adequate license from
   the person(s) controlling the copyright in such materials, this
   document may not be modified outside the IETF Standards Process, and
   derivative works of it may not be created outside the IETF Standards
   Process, except to format it for publication as an RFC or to
   translate it into languages other than English.

   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
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on October 2, 2009.

Copyright Notice



Montemurro, et al.       Expires October 2, 2009                [Page 1]


Internet-Draft           The GSMA and IMEI URNs               March 2009


   Copyright (c) 2009 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 in effect on the date of
   publication of this document (http://trustee.ietf.org/license-info).
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.

Abstract

   This specification defines a Uniform Resource Name namespace for the
   GSMA and sub namespaces for the IMEI (International Mobile station
   Equipment Identity), and for the IMEISV (International Mobile station
   Equipment Identity and Software Version number).  The IMEI is 15
   decimal digits long and the IMEISV is 16 decimal digits long and both
   are encoded using Binary Encoded Decimal (BCD).  The IMEI and IMEISV
   were introduced as part of the specification for Global System for
   Mobile (GSM) and are also now incorporated by the 3rd Generation
   Partnership Project (3GPP) as part of the 3GPP specification for GSM,
   and the Universal Mobile Telecommunications System (UMTS).  The IMEI
   and IMEISV are used to uniquely identify Mobile Equipment within
   these systems and are managed by the GSMA (GSM Association).




























Montemurro, et al.       Expires October 2, 2009                [Page 2]


Internet-Draft           The GSMA and IMEI URNs               March 2009


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4

   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  5

   3.  Namespace Registration Template  . . . . . . . . . . . . . . .  5
     3.1.  GSMA . . . . . . . . . . . . . . . . . . . . . . . . . . .  5

   4.  Specification  . . . . . . . . . . . . . . . . . . . . . . . .  8
     4.1.  IMEI Format  . . . . . . . . . . . . . . . . . . . . . . .  8
       4.1.1.  Type Allocation Code (TAC) . . . . . . . . . . . . . .  9
       4.1.2.  Serial Number (SNR)  . . . . . . . . . . . . . . . . .  9
       4.1.3.  Spare  . . . . . . . . . . . . . . . . . . . . . . . .  9
     4.2.  IMEISV Format  . . . . . . . . . . . . . . . . . . . . . .  9
       4.2.1.  Type Allocation Code (TAC) . . . . . . . . . . . . . . 10
       4.2.2.  Serial Number (SNR)  . . . . . . . . . . . . . . . . . 10
       4.2.3.  Software Version Number (SVN)  . . . . . . . . . . . . 10

   5.  Community considerations . . . . . . . . . . . . . . . . . . . 10

   6.  Use as an Instance ID  . . . . . . . . . . . . . . . . . . . . 10

   7.  Namespace considerations . . . . . . . . . . . . . . . . . . . 10

   8.  IANA considerations  . . . . . . . . . . . . . . . . . . . . . 11

   9.  Security considerations  . . . . . . . . . . . . . . . . . . . 11

   10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11

   11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     11.1. Normative references . . . . . . . . . . . . . . . . . . . 11
     11.2. Informative references . . . . . . . . . . . . . . . . . . 12

   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12















Montemurro, et al.       Expires October 2, 2009                [Page 3]


Internet-Draft           The GSMA and IMEI URNs               March 2009


1.  Introduction

   This specification defines a Uniform Resource Name namespace for the
   GSMA (GSM Association) and sub namespaces for the IMEI (International
   Mobile station Equipment Identity), and for the IMEISV (International
   Mobile station Equipment Identity and Software Version number as per
   the namespace registration requirement found in [1].  GSMA is an
   identifier for a namespace for identities used by Mobile Equipment
   used in GSM and UMTS networks.  The IMEI and the IMEISV are managed
   by the GSMA, so this namespace would be managed by the GSMA.  Whilst
   this specification currently specifies only the IMEI and IMEISV sub
   namespaces under the GSMA URN namespace additional sub namespaces
   under the GSMA namespace may be specified in the future by the GSMA
   through the publication of future informational RFCs.

   The IMEI is 15 decimal digits long and includes a Type Allocation
   Code (TAC) of 8 decimal digits and the Serial Number (SNR) of 6
   decimal digits plus a Spare decimal digit.  The TAC identifies the
   type of the Mobile Equipment and is chosen from a range of values
   allocated to the Mobile Equipment manufacturer in order to uniquely
   identify the model of the Mobile Equipment.  The SNR is an individual
   serial number that uniquely identifies each Mobile Equipment within
   the TAC.  The Spare digit is used as a security check to combat
   potential spoofing and is always set to the value 0 when transmitted
   by the Mobile Equipment.

   The IMEISV is 16 decimal digits long and includes the TAC and SNR
   same as for the IMEI but also a 2 decimal digit Software Version
   Number (SVN) which is allocated by the Mobile Equipment manufacturer
   to identify the software version of the Mobile Equipment.

   The IMEI is specified to be stored in a tamper proof fashion so that
   it cannot be overwritten or otherwise reprogrammed by software.

   The information here is meant to be a concise guide for those wishing
   to use the IMEI and IMEISV as URNs.  Nothing in this document should
   be construed to override 3GPP TS 23.003 [2] that defines the IMEI and
   IMEISV.

   The GSM Association (GSMA) is a global trade association representing
   more than 750 GSM mobile phone operators across 218 territories and
   countries of the world.  The primary goals of the GSMA are to ensure
   mobile phones and wireless services work globally and are easily
   accessible.  Further details about the GSMA role in allocating the
   IMEI and the IMEISV and the IMEI and IMEISV allocation guidelines can
   be found in GSMA PRD DG.06 [3]





Montemurro, et al.       Expires October 2, 2009                [Page 4]


Internet-Draft           The GSMA and IMEI URNs               March 2009


2.  Terminology

   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 [4].


3.  Namespace Registration Template

3.1.  GSMA

   Namespace ID:  "gsma" requested

   Registration Information:

   Registration version number:  1

   Registration date:  2006-10-11

   Declared registrant of the namespace:  GSM Association, 1st Floor,
      Mid City Place, 71 High Holborn, London, England

   Declaration of syntactic structure:
      The identifier is expressed in ASCII (UTF-8) characters and has a
      hierarchical structure as follows:


         urn:gsma:<gsma-specifier>[:<gsma-specifier-defined-string>]+
         where
          <gsma-specifier>  = "imei" | "imeisv"
          <gsma-specifier-defined-string>  = GSMA-approved string
          +  = one or more occurences of "gsma-specifier-defined-string"


      The GSMA namespace includes two predefined namespaces IMEI and
      IMEISV and may be in the future extended to include other
      identifiers used by Mobile Equipment used in GSM and UMTS networks
      or future networks deployed by members of the GSMA.


      A IMEI is an identifier under the GSMA namespace that uniquely
      identifies Mobile Equipment used in GSM and UMTS networks.

      The internal representation of a IMEI is a specific sequence of
      bits in memory, as described in 3GPP TS 23.003 [2].  To accurately
      represent a IMEI as a URN, it is necessary to convert the BCD bit
      sequence to a string representation.  Each field BCD bit sequence
      has its value printed as a decimal digit string with the most



Montemurro, et al.       Expires October 2, 2009                [Page 5]


Internet-Draft           The GSMA and IMEI URNs               March 2009


      significant digit first.

      The following augmented Backus-Naur Form (ABNF) includes the set
      of core rules in RFC 5234 [8], and are not repeated here.

      The formal definition of the IMEI string representation is
      provided by the following ABNF [8]:

      IMEI =  tac "-" snr "-" spare
      tac      = 8DIGIT
      snr      = 6DIGIT
      spare    = 1DIGIT
      For example:
         urn:gsma:imei:90420156-025763-0

      A IMEISV is an identifier under the GSMA namespace that uniquely
      identifies Mobile Equipment and associated software versions used
      in GSM and UMTS networks.  The internal representation of a IMEISV
      is a specific sequence of bits in memory, as described in 3GPP TS
      23.003 [2].  To accurately represent a IMEISV as a URN, it is
      necessary to convert the BCD bit sequence to a string
      representation.  Each field BCD bit sequence has its value printed
      as a decimal digit string with the most significant digit first.

      The formal definition of the IMEISV string representation is
      provided by the following ABNF [8]:

      IMEISV =  tac "-" snr "-" svn
      tac      = 8DIGIT
      snr      = 6DIGIT
      svn      = 2DIGIT
      For example:
         urn:gsma:imeisv:90420156-025763-42

      The <gsma-specifier> and <gsma-specifier defined string> can
      comprise any ASCII characters compliant with URI syntax and must
      not contain the ":" character (see STD 66, RFC 3986 [5]).  The
      exclusion of the colon from the list of other characters means
      that the colon can only occur as a delimiter between string
      values.

      The GSMA will take responsibility for the gsma-specifier "imei"
      and "imeisv" and manage the sub level.








Montemurro, et al.       Expires October 2, 2009                [Page 6]


Internet-Draft           The GSMA and IMEI URNs               March 2009


      Additional gsma-specifiers may be added in the future through
      informational RFCs.

   Relevant ancillary documentation:
      See IMEI Allocation and Approval Guidelines [3] and 3GPP TS 23.003
      [2].

   Identifier uniqueness considerations:
      Identifiers in the "gsma" namespace are defined and assigned in
      the requested namespace by the GSMA after ensuring that the URNs
      to be assigned are unique.  Uniqueness is achieved by checking
      against the registry of previously assigned names.

      Procedures are in place to ensure that each IMEI is uniquely
      assigned by the Mobile Equipment manufacturer so that it is
      guaranteed to uniquely identify that particular Mobile Equipment.
      IMEIs are stored in the Mobile Equipment in a tamper proof non
      modifiable fashion so they remain persistent.
      Procedures are in place to ensure that each IMEISV is uniquely
      assigned by the Mobile Equipment manufacturer so that it is
      guaranteed to uniquely identify that particular Mobile Equipment
      and the specific software version installed.

   Identifier persistence considerations:
      The GSMA is committed to maintaining uniqueness and persistence of
      all resources identified by assigned URNs.

      As the NID sought is "gsma" and GSMA is the long standing acronym
      for the trade association that represents the mobile phone
      operators the URN should also persist indefinitely (at least as
      long as there is a need for its use).  The assignment process
      guarantees that names are not reassigned.  The binding between the
      name and its resource is permanent.

      IMEIs are stored in Mobile Equipment in a tamper proof non-
      modifiable fashion so they remain persistent
      The TAC and SNR portions of IMEISVs are stored in the Mobile
      Equipment in a tamper proof non modifiable fashion so they remain
      persistent.  The SVN may be modified by software when new versions
      are installed but should be persistent for the duration of the
      installation of that specific version of software.

   Process of identifier assignment:
      GSMA will manage the <gsma-specifier> and <gsma-defined string>
      including "imei" and "imeisv" identifier resources to maintain
      uniqueness.





Montemurro, et al.       Expires October 2, 2009                [Page 7]


Internet-Draft           The GSMA and IMEI URNs               March 2009


      The process for IMEI and IMEISV assignment is documented in GSMA
      PRD DG.06[3]


   Process for identifier resolution:
      Since the GSMA namespace is not globally resolvable, this is not
      applicable.

   Rules for Lexical Equivalence:
      Consider each field of the IMEI or IMEISV to be a sequence of
      decimial digits.  Then, to compare a pair of IMEIs or IMEISVs,
      arithmetically compare the corresponding fields from each IMEI or
      IMEISV in order of significance and according to their data type.
      Two IMEIs or IMEISVs are equal if and only if all the
      corresponding fields are equal.

      The lexical equivalence of the GSMA namespace-specific strings
      (NSSs) is defined as an exact, but not case-sensitive, string
      match.

      Any identifier in GSMA namespaces can be compared using the normal
      mechanisms for percent-encoded UTF-8 strings.

   Conformance with URN Syntax:
      The string representation of the GSMA URN and of the IMEI and
      IMEISV subnamespaces is fully compatible with the URN syntax.

   Validation Mechanism:
      The IMEI can be validated using the mechanism defined in Annex B
      of 3GPP TS 23.003 [2].  The TAC and SNR fields of the IMEISV can
      be validated using the mechanism defined in Annex B of 3GPP TS
      23.003 [2].  There is no mechanism defined to validate the SVN
      field of the IMEISV.

   Scope:  GSMA URN is global in scope.



4.  Specification

4.1.  IMEI Format

   The IMEI format is 15 decimal digits encoded in 8 octets using BCD as
   defined in 3GPP TS 24.008 [6].  The most significant digit is coded
   in the most significant bits of octet 1.  The least significant digit
   is coded in the least significant bits of octet 8.





Montemurro, et al.       Expires October 2, 2009                [Page 8]


Internet-Draft           The GSMA and IMEI URNs               March 2009


       14 13 12 11 10  9  8  7  6  5  4  3  2  1  0  Decimal Digits
      +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
      |                       |                 | S|
      |            T          |          S      | p|
      |            A          |          N      | a|
      |            C          |          R      | r|
      |                       |                 | e|
      +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
         1     2     3     4     5     6     7     8  Octets


4.1.1.  Type Allocation Code (TAC)

   The TAC is a 8 decimal digit value.  The TAC identifies the type of
   the Mobile Equipment and is chosen from a range of values allocated
   to the Mobile Equipment manufacturer in order to uniquely identify
   the model of the Mobile Equipment.

4.1.2.  Serial Number (SNR)

   The SNR is a 6 decimal digit value.  The SNR is an individual serial
   number that uniquely identifies each Mobile Equipment within the TAC.

4.1.3.  Spare

   The Spare is a single decimal digit that is used as a security check
   digit to combat potential spoofing.  The Spare is always set to zero
   when transmitted by the Mobile Equipment.  Annex B of 3GPP TS 23.003
   [2] defines a mechanism for computing the actual check digit in order
   to validate the TAC and SNR.

4.2.  IMEISV Format

   The IMEISV format is 16 decimal digits encoded in 8 octets using BCD
   as defined in 3GPP TS 24.008 [6].  The most significant digit is
   coded in the most significant bits of octet 1.  The least significant
   digit is coded in the least significant bits of octet 8.

       15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0  Decimal Digits
      +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
      |                       |                 |     |
      |            T          |          S      |  S  |
      |            A          |          N      |  V  |
      |            C          |          R      |  N  |
      |                       |                 |     |
      +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
            1     2     3     4     5     6     7     8  Octets




Montemurro, et al.       Expires October 2, 2009                [Page 9]


Internet-Draft           The GSMA and IMEI URNs               March 2009


4.2.1.  Type Allocation Code (TAC)

   The TAC is the same as for the IMEI in Section 5.1.1.

4.2.2.  Serial Number (SNR)

   The SNR is the same as for the IMEI in Section 5.1.2.

4.2.3.  Software Version Number (SVN)

   The Software Version Number is allocated by the Mobile Equipment
   manufacturer to identify the software version of the Mobile
   Equipment.


5.  Community considerations

   GSM and UMTS mobile devices will be interoperating with Internet
   devices for a variety of voice and data services.  To do this, they
   need to make use of Internet protocols that will operate end to end
   between devices in GSM/UMTS networks and those in the general
   internet.  Many of these protocols require the use of URN's as
   identifiers.  Within the GSM/UMTS networks, mobile devices are
   identified by their IMEI and IMEISV.  Internet users will need to be
   able to receive and include the GSMA URN in various Internet protocol
   elements to facilitate communication between pure internet based
   devices and GSM and UMTS mobile devices.  Thus the existence and
   syntax of these namespaces needs to be available to the general
   internet community and the namespace needs to be reserved with IANA
   in order to guarantee uniqueness and prevent potential namespace
   conflicts both within the internet and within GSM/UMTS networks.


6.  Use as an Instance ID

   The IMEI and IMEISV URNs MAY be used as an Instance ID and included
   in the sip.instance parameter of a Contact header field of a SIP
   Register request as specified in draft-ietf-sip-outbound [9].


7.  Namespace considerations

   A URN was considered the most appropriate URI to represent the IMEI
   and IMEISV as these identifiers may be used and transported similarly
   to the Universally Unique Identifier (UUID)which is defined as a URN
   in [10].  Since specifications for protocols that are used to
   transport device identifiers often require the device identifier to
   be globally unique and in the URN format it is necessary that the



Montemurro, et al.       Expires October 2, 2009               [Page 10]


Internet-Draft           The GSMA and IMEI URNs               March 2009


   IMEI and IMEISV URN formats are defined.


8.  IANA considerations

   In accordance with BCP 66 [1], IANA is asked to register the Formal
   URN Namespace 'GSMA' in the Registry of URN Namespaces, using the
   registration template presented in Section 3 of this document.


9.  Security considerations

   IMEIs (with the Spare value set to zero) are displayable on most
   Mobile Equipment; therefore, they must not be used as security
   capabilities (identifiers whose mere possession grants access), for
   example.

   Revealing the specific software version of the terminal might make
   the terminal more vulnerable to attacks against software that is
   known to contain security holes.  This is a similar concern to the
   use of the User-Agent header in SIP as specified in RFC 3261 [11].
   It is therefore RECOMMENDED that the IMEISV is not delivered to
   devices that are not trusted.  Care should be taken regarding use of
   the IMEISV as it could help a malicious device identify Mobile
   Equipment running software that is known to be vulnerable to certain
   attacks.

   Additional security considerations are specified in 3GPP TS 22.016
   [7].  Specifically the IMEI is to be incorporated in a module which
   is contained within the terminal.  The IMEI SHALL not be changed
   after the terminal's production process.  It SHALL resist tampering,
   i.e. manipulation and change, by any means (e.g. physical, electrical
   and software).


10.  Acknowledgements

   This document draws heavily on the 3GPP work on Numbering, Addressing
   and Identification in 3GPP TS 23.003 [2] and also on the style and
   structure used in RFC 4122 [10].


11.  References

11.1.  Normative references

   [1]   Daigle, L., van Gulik, D., Iannella, R., and P. Faltstrom,
         "Uniform Resource Names (URN) Namespace Definition Mechanisms",



Montemurro, et al.       Expires October 2, 2009               [Page 11]


Internet-Draft           The GSMA and IMEI URNs               March 2009


         BCP 66, RFC 3406, October 2002.

   [2]   3GPP, "TS 23.003: Numbering, addressing and identification
         (Release 8)", 3GPP 23.003, September 2008,
         <ftp://ftp.3gpp.org/Specs/archive/23_series/23.003/>.

   [3]   GSMA Association, "IMEI Allocation and Approval Guidelines",
         PRD DG.06 version 3.6, February 2008,
         <http://www.gsmworld.com/documents/twg/dg06_3v6.pdf>.

   [4]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels", BCP 14, RFC 2119, March 1997.

   [5]   Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
         Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986,
         January 2005.

   [6]   3GPP, "TS 24.008: Mobile radio interface Layer 3 specification;
         Core network protocols; Stage 3 (Release 8)", 3GPP 24.008,
         September 2008,
         <ftp://ftp.3gpp.org/Specs/archive/24_series/24.008/>.

   [7]   3GPP, "TS 22.016: International Mobile station Equipment
         Identities (IMEI)(Release 7)", 3GPP 22.016, May 2007,
         <ftp://ftp.3gpp.org/Specs/archive/22_series/22.016/>.

11.2.  Informative references

   [8]   Crocker, D. and P. Overell, "Augmented BNF for Syntax
         Specifications: ABNF", STD 68, RFC 5234, January 2008.

   [9]   Jennings, C. and R. Mahy, "Managing Client Initiated
         Connections in the Session Initiation Protocol  (SIP)",
         draft-ietf-sip-outbound-16 (work in progress), October 2008.

   [10]  Leach, P., Mealling, M., and R. Salz, "A Universally Unique
         IDentifier (UUID) URN Namespace", RFC 4122, July 2005.

   [11]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
         Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP:
         Session Initiation Protocol", RFC 3261, June 2002.










Montemurro, et al.       Expires October 2, 2009               [Page 12]


Internet-Draft           The GSMA and IMEI URNs               March 2009


Authors' Addresses

   Michael Montemurro (editor)
   Research in Motion (RIM)
   4701 Tahoe Dr
   Mississauga, Ontario  L4W 0B4
   Canada

   Phone: unlisted
   Fax:   unlisted
   Email: mmontemurro@rim.com


   Andrew Allen
   Research in Motion (RIM)
   300 Knightsbridge Parkway, Suite 360
   Lincolnshire, Illinois  60069
   USA

   Phone: unlisted
   Fax:   unlisted
   Email: aallen@rim.com


   David McDonald
   unaffiliated

   Phone: unlisted
   Fax:   unlisted
   Email: mcdonalddm@hotmail.com


   Paul Gosden
   GSM Association
   1st Floor, Mid City Place, 71 High Holborn,
   London
   England

   Phone: unlisted
   Fax:   unlisted
   Email: pgosden@gsm.org










Montemurro, et al.       Expires October 2, 2009               [Page 13]