Network Working Group M. Montemurro, Ed. Internet-Draft A. Allen Intended status: Informational Research in Motion (RIM) Expires: April 3, 2009 D. McDonald unaffiliated P. Gosden GSM Association September 30, 2008 A Uniform Resource Name Namespace For The GSM Association (GSMA) and the International Mobile station Equipment Identity(IMEI) draft-montemurro-gsma-imei-urn-02 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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 April 3, 2009. 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 are both encoded using Binary Encoded Decimal (BCD). The IMEI and IMEISV were introduced as part of the specification for Global System for Montemurro, et al. Expires April 3, 2009 [Page 1] Internet-Draft The GSMA and IMEI URNs September 2008 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). Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Namespace Registration Template . . . . . . . . . . . . . . . 4 3.1. GSMA . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Specification . . . . . . . . . . . . . . . . . . . . . . . . 7 4.1. IMEI Format . . . . . . . . . . . . . . . . . . . . . . . 7 4.1.1. Type Allocation Code (TAC) . . . . . . . . . . . . . . 8 4.1.2. Serial Number (SNR) . . . . . . . . . . . . . . . . . 8 4.1.3. Spare . . . . . . . . . . . . . . . . . . . . . . . . 8 4.2. IMEISV Format . . . . . . . . . . . . . . . . . . . . . . 8 4.2.1. Type Allocation Code (TAC) . . . . . . . . . . . . . . 9 4.2.2. Serial Number (SNR) . . . . . . . . . . . . . . . . . 9 4.2.3. Software Version Number (SVN) . . . . . . . . . . . . 9 5. Community considerations . . . . . . . . . . . . . . . . . . . 9 6. Use as an Instance ID . . . . . . . . . . . . . . . . . . . . 9 7. Namespace considerations . . . . . . . . . . . . . . . . . . . 9 8. Security considerations . . . . . . . . . . . . . . . . . . . 10 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10 10.1. Normative references . . . . . . . . . . . . . . . . . . . 10 10.2. Informative references . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11 Intellectual Property and Copyright Statements . . . . . . . . . . 13 Montemurro, et al. Expires April 3, 2009 [Page 2] Internet-Draft The GSMA and IMEI URNs September 2008 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 April 3, 2009 [Page 3] Internet-Draft The GSMA and IMEI URNs September 2008 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::[]+ where = "imei" | "imeisv" = 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 significant digit first. Montemurro, et al. Expires April 3, 2009 [Page 4] Internet-Draft The GSMA and IMEI URNs September 2008 The formal definition of the IMEI string representation is provided by the following ABNF [5] IMEI = tac "-" snr "-" spare tac = 8Digit snr = 6Digit spare = 1Digit decDigit = "0" / "1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9" 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 [5] IMEISV = tac "-" snr "-" svn tac = 8Digit snr = 6Digit svn = 2Digit decDigit = "0" / "1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9" For example: urn:gsma:imeisv:90420156-025763-42 The and can comprise any ASCII characters compliant with URI syntax and must not contain the ":" character (see STD 66, RFC 3986 [6]). 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 April 3, 2009 [Page 5] Internet-Draft The GSMA and IMEI URNs September 2008 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 and including "imei" and "imeisv" identifier resources to maintain uniqueness. Montemurro, et al. Expires April 3, 2009 [Page 6] Internet-Draft The GSMA and IMEI URNs September 2008 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 [7]. The most significant digit is coded in the least significant bits of octet 1. The least significant digit is coded in the least significant bits of octet 8. Montemurro, et al. Expires April 3, 2009 [Page 7] Internet-Draft The GSMA and IMEI URNs September 2008 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 [7]. 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 April 3, 2009 [Page 8] Internet-Draft The GSMA and IMEI URNs September 2008 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 [8]. 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 [9]. 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 April 3, 2009 [Page 9] Internet-Draft The GSMA and IMEI URNs September 2008 IMEI and IMEISV URN formats are defined. 8. 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 [10]. 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 [11]. Specifically the IMEI is to be incorporated in a module which is contained within the terminal. The IMEI SHALL not be chnaged after the terminal's production process. It SHALL resist tampering, i.e. manipulation and change, by any means (e.g. physical, electrical and software). 9. 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 [9]. 10. References 10.1. Normative references [1] Daigle, L., van Gulik, D., Iannella, R., and P. Faltstrom, "Uniform Resource Names (URN) Namespace Definition Mechanisms", BCP 66, RFC 3406, October 2002. [2] 3GPP, "TS 23.003: Numbering, addressing and identification (Release 8)", 3GPP 23.003, September 2008, . [3] GSMA Association, "IMEI Allocation and Approval Guidelines", Montemurro, et al. Expires April 3, 2009 [Page 10] Internet-Draft The GSMA and IMEI URNs September 2008 PRD DG.06 version 3.6, February 2008, . [4] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [5] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 4234, October 2005. [6] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005. [7] 3GPP, "TS 24.008: Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 (Release 8)", 3GPP 24.008, September 2008, . 10.2. Informative references [8] Jennings, C. and R. Mahy, "Managing Client Initiated Connections in the Session Initiation Protocol (SIP)", draft-ietf-sip-outbound-15 (work in progress), June 2008. [9] Leach, P., Mealling, M., and R. Salz, "A Universally Unique IDentifier (UUID) URN Namespace", RFC 4122, July 2005. [10] 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. [11] 3GPP, "TS 22.016: International Mobile station Equipment Identities (IMEI)(Release 7)", 3GPP 22.016, May 2007, . Authors' Addresses Michael Montemurro (editor) Research in Motion (RIM) 5090 Commerce Blvd Mississauga, Ontario L4W 5W4 Canada Phone: unlisted Fax: unlisted Email: mmontemurro@rim.com Montemurro, et al. Expires April 3, 2009 [Page 11] Internet-Draft The GSMA and IMEI URNs September 2008 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 April 3, 2009 [Page 12] Internet-Draft The GSMA and IMEI URNs September 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). 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