Network Working Group M. Montemurro, Ed. Internet-Draft A. Allen Intended status: Experimental Research in Motion (RIM) Expires: August 6, 2007 D. McDonald GSM Association February 2, 2007 A Uniform Resource Name Namespace For The GSM Association (GSMA) and the International Mobile station Equipment Identity(IMEI) draft-montemurro-gsma-imei-urn-01 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 August 6, 2007. Copyright Notice Copyright (C) The IETF Trust (2007). 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 Montemurro, et al. Expires August 6, 2007 [Page 1] Internet-Draft The GSMA and IMEI URNs February 2007 both 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). Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Namespace Registration Template . . . . . . . . . . . . . . . 5 4.1. GSMA . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 5. Specification . . . . . . . . . . . . . . . . . . . . . . . . 9 5.1. IMEI Format . . . . . . . . . . . . . . . . . . . . . . . 9 5.1.1. Type Allocation Code (TAC) . . . . . . . . . . . . . . 10 5.1.2. Serial Number (SNR) . . . . . . . . . . . . . . . . . 10 5.1.3. Spare . . . . . . . . . . . . . . . . . . . . . . . . 10 5.2. IMEISV Format . . . . . . . . . . . . . . . . . . . . . . 10 5.2.1. Type Allocation Code (TAC) . . . . . . . . . . . . . . 10 5.2.2. Serial Number (SNR) . . . . . . . . . . . . . . . . . 10 5.2.3. Software Version Number (SVN) . . . . . . . . . . . . 11 6. Community considerations . . . . . . . . . . . . . . . . . . . 11 7. Namespace considerations . . . . . . . . . . . . . . . . . . . 11 8. Security considerations . . . . . . . . . . . . . . . . . . . 11 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 10.1. Normative references . . . . . . . . . . . . . . . . . . . 12 10.2. Informative references . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 Intellectual Property and Copyright Statements . . . . . . . . . . 14 Montemurro, et al. Expires August 6, 2007 [Page 2] Internet-Draft The GSMA and IMEI URNs February 2007 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]. 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. 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 690 GSM mobile phone operators across 214 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 TW.06 [3] Montemurro, et al. Expires August 6, 2007 [Page 3] Internet-Draft The GSMA and IMEI URNs February 2007 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. Motivation The theft of mobile phones has become a significant problem in many countries and often involves the use of violence and intimidation which is frequently perpetrated against children. The ability of the network to identify that a stolen mobile is being used and identify the subscription that is using it or to prevent its use should help to reduce these problems. The potential for damage by malfunctioning mobiles is also of increasing concern. In earlier times when there was a limited well specified set of features and services that were defined for Mobile Equipment it was possible to define and conduct rigorous conformance testing of the Mobile Equipment to ensure its appropriateness for use on the Cellular network. Now however as the networks and services are becoming much more complex, varied and feature rich and with the associated drive for rapid deployment of new services leveraging the great flexibility provided by Internet Protocols this kind of rigorous conformance testing of every service, application and capability is becoming no longer viable. As a result it is more likely that Mobile Equipment commercially deployed in the networks in future will not always exhibit the correct behaviors under all circumstances. Sometimes this may result in more than just dissatisfaction for a particular mobile user but could potentially result in an unintended Denial of Service (DoS) attack on the network that could potentially impact thousands of other users. The use of the IMEISV is additionally helpful in this respect as it allows specific problematic software versions of Mobile Equipment to be identified so that appropriate defensive or corrective action can be taken. There is also increasing concern that the increasingly disturbing phenomenon of malware such as viruses and other trojans will rapidly spread to Mobile Equipment. This equipment has become more computer like through the increasing use of smartphones and PDAs with standardized Operating Systems. Such devices provide support for downloadable installable applications and the communication ability through peer to peer IP to deliver these programs from one Mobile Phone to another. There is a real concern that once the appearance of malware viruses on Mobile Equipment becomes common that coordinated DoS attacks could be conducted against Mobile Networks by Montemurro, et al. Expires August 6, 2007 [Page 4] Internet-Draft The GSMA and IMEI URNs February 2007 possibly millions of mobile phones. Since the bandwidth capabilities of Cellular Networks are an order of magnitude lower than those of broadband access networks it is potentially much easier to congest a cellular network through a coordinated attack than the fixed network. These networks are also already relied upon for Emergency Services so the consequences of widespread network failure through coordinated Mobile Phone virus DoS attack are potentially much more severe. The IMEI can play a significant role in identifying Mobile Equipment that is known to be infected with viruses and to prevent its use and limit potential damage to the operation of the network and the Mobile Equipment of other users. Likewise the IMEISV can help identify Mobile Equipment running software versions vulnerable to attack by such malware. Currently GSM and UMTS network lower layers provide the ability to transport the IMEI and IMEISV between the Mobile Equipment and the network. However these networks are now transitioning to IP Core Networks such as the 3GPP IP Multimedia Subssytem (IMS) where the cellular access network signaling is becoming decoupled from the IP based network and applications such that it is becoming more difficult for the session and application layers to obtain the IMEI and IMEISV of the Mobile Equipment involved in the session or accessing the application or server. Also access for Mobile Equipment to these networks is now being extended via non cellular access technologies such as WLAN and Bluetooth and various broadband technologies that do not provide any transport layer support for the IMEI or IMEISV. It is therefore necessary that support for transport of these identifiers by IP protocols be provided by defining URNs for them. 4. Namespace Registration Template 4.1. GSMA Namespace ID: "gsma" requested Registration Information: Registration date: 2006-10-11 Declared registrant of the namespace: GSMA. Declaration of syntactic structure: Montemurro, et al. Expires August 6, 2007 [Page 5] Internet-Draft The GSMA and IMEI URNs February 2007 GSMA is an identifier for a namespace for identifiers used by Mobile Equipment used in GSM and UMTS networks. The identifier is expressed in ASCII (UTF-8) characters and has a hierarchical structure as follows: urn:gsma:[]+ where = "imei" | "imeisv" | = GSMA-approved specifier to be defined = GSMA-approved string to be defined + = 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. The formal definition of the IMEISV string representation is provided by the following ABNF [5] IMEI = tac "-" snr "-" svn tac = 8decDigit snr = 6decDigit spare = 1decDigit 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 Montemurro, et al. Expires August 6, 2007 [Page 6] Internet-Draft The GSMA and IMEI URNs February 2007 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 = 8decDigit snr = 6decDigit svn = 2decDigit 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". The GSMA will take responsibility to assign other gsma-specifiers and manage the sub level and its applicable gsma-specifier defined string(s). Relevant ancillary documentation: None. 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. Montemurro, et al. Expires August 6, 2007 [Page 7] Internet-Draft The GSMA and IMEI URNs February 2007 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. The process of assigning additional URNs at the sub-level will be managed by the GSMA. The process for IMEI and IMEISV assignment is documented in GSMA PRD TW.06 [3] Process for identifier resolution: Since the GSMA namespace is not globally resolvable, this is not applicable. 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. Montemurro, et al. Expires August 6, 2007 [Page 8] Internet-Draft The GSMA and IMEI URNs February 2007 Rules for Lexical Equivalence: 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. 5. Specification 5.1. IMEI Format The IMEI format is 15 decimal digits encoded in 8 octets using BCD as defined in 3GPP TS 24.008 [7]. The least significant digit is coded in the 1st 3 bits of octet 1. The most significant digit is coded in the least significant bits of octet 8. Last 4 digits of octet 8 are all 1's. 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 Decimal Digits +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | |S| | T | S |p| | A | N |a| | C | R |r| | | |e| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1 2 3 4 5 6 7 8 Octets Montemurro, et al. Expires August 6, 2007 [Page 9] Internet-Draft The GSMA and IMEI URNs February 2007 5.1.1. 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. 5.1.2. 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 5.1.3. 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. 5.2. IMEISV Format The IMEISV format is 16 decimal digits encoded in 8 octets using BCD as defined in 3GPP TS 24.008 [7]. The least significant digit is coded in the 1st 3 bits of octet 1. The most significant digit is coded in the least significant bits of octet 8. 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 Decimal Digits +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | | | T | S | S | | A | N | V | | C | R | N | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1 2 3 4 5 6 7 8 Octets 5.2.1. Type Allocation Code (TAC) The TAC is the same as for the IMEI in Section 5.1.1. 5.2.2. Serial Number (SNR) The SNR is the same as for the IMEI in Section 5.1.2. Montemurro, et al. Expires August 6, 2007 [Page 10] Internet-Draft The GSMA and IMEI URNs February 2007 5.2.3. Software Version Number (SVN) The Software Version Number is allocated by the Mobile Equipment manufacturer to identify the software version of the Mobile Equipment. 6. Community considerations 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 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. 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. This is a similar concern to the use of the User-Agent header in SIP as specified in RFC 3261 [8]. Additional security considerations are specified in 3GPP TS 22.016 [9]. 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 [10]. 10. References Montemurro, et al. Expires August 6, 2007 [Page 11] Internet-Draft The GSMA and IMEI URNs February 2007 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 7)", 3GPP 23.003, June 2006, . [3] GSMA Assocaition, "IMEI Allocation and Approval Guidelines", PRD TW.06 version 3.3.0, December 2004, . [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 7)", 3GPP 24.008, June 2006, . 10.2. Informative references [8] 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. [9] 3GPP, "TS 22.016: International Mobile station Equipment Identities (IMEI)(Release 6)", 3GPP 22.016, January 2005, . [10] Leach, P., Mealling, M., and R. Salz, "A Universally Unique IDentifier (UUID) URN Namespace", RFC 4122, July 2005. Montemurro, et al. Expires August 6, 2007 [Page 12] Internet-Draft The GSMA and IMEI URNs February 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 Andrew Allen Research in Motion (RIM) 102 Decker Court, Suite 100 Irving, Texas 75062 USA Phone: unlisted Fax: unlisted Email: aallen@rim.com David McDonald GSM Association Block 2, Deansgrange Business Park Deansgrange, Co. Dublin Ireland Phone: unlisted Fax: unlisted Email: DMcDonald@gsm.org Montemurro, et al. Expires August 6, 2007 [Page 13] Internet-Draft The GSMA and IMEI URNs February 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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