Dispatch Working Group                                     A. Allen, Ed.
Internet-Draft                                  Research in Motion (RIM)
Intended status: Informational                          January 11, 2011
Expires: July 15, 2011


Using the International Mobile station Equipment Identity(IMEI)URN as an
                              Instance ID
             draft-allen-dispatch-imei-urn-as-instanceid-02

Abstract

   This specification defines how the Uniform Resource Name namespace
   reserved for GSMA (Global Sstandard for Mobiles Association)
   identities and its sub namespace for the IMEI (International Mobile
   station Equipment Identity) can be used as an instance-id as
   specified in RFC 5626 [1] and also as used by RFC 5627 [2].

Status of this Memo

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   This Internet-Draft will expire on July 15, 2011.

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   described in the Simplified BSD License.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3

   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3

   3.  Background  . . . . . . . . . . . . . . . . . . . . . . . . . . 4

   4.  User Agent Client Procedures  . . . . . . . . . . . . . . . . . 5

   5.  Security considerations . . . . . . . . . . . . . . . . . . . . 5

   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 5

   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 6
     7.1.  Normative references  . . . . . . . . . . . . . . . . . . . 6
     7.2.  Informative references  . . . . . . . . . . . . . . . . . . 6

   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 7





























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1.  Introduction

   This specification defines how the Uniform Resource Name namespace
   reserved for GSMA identities and its sub namespace for the IMEI
   (International Mobile station Equipment Identity) as defined in
   draft-montemurro-gsma-imei-urn-06 [3] can be used as an instance-id
   as specified in RFC 5626 [1] and also as used by RFC 5627 [2].

   RFC 5626 [1] defines the "+sip.instance" Contact header field
   parameter which contains a URN as per RFC 2141 [4] defined as an
   instance-id that uniquely identifies a specific UA instance.  This
   instance-id is used as defined in RFC 5626 [1] so that registrar can
   recognize that the contacts from multiple registrations correspond to
   the same UA.  The instance-ID is also used as defined by RFC 5627 [2]
   to create Globally Routable User Agent URIs (GRUUs) that can be used
   to uniquely address a UA when multiple UAs are registered with the
   same Address of Record (AoR).

   RFC 5626 [1] defines that a UA SHOULD create a Universally Unique
   Identifier (UUID) URN as defined in RFC 4122 [6] as its instance-id
   but allows for the possibility of other URN schemes to be used.  If a
   URN scheme other than UUID is used, the UA MUST only use URNs for
   which an RFC (from the IETF stream) defines how the specific URN
   needs to be constructed and used in the "+sip.instance" Contact
   header field parameter for outbound behavior.  This specification
   meets this requirement by specifying how the GSMA IEMEI URN is used
   in the "+sip.instance" Contact header field parameter for outbound
   behavior and draft-montemurro-gsma-imei-urn-06 [3] defines how the
   GSMA IMEI URN is constructed

   The GSMA IMEI is an identifier for a namespace for the IMEI a
   globally unique identifier that identifies Mobile Equipment used in
   Global System for Mobile (GSM), Universal Mobile Telecommunications
   System (UMTS) and 3GPP LTE (Long Term Evolution)networks.  The IMEI
   allocation is managed by the GSMA to ensure that the IMEI values are
   globally unique.  Details of the formatting of the IMEI as a URN are
   defined in draft-montemurro-gsma-imei-urn-06 [3] and the definition
   of the IMEI is contained in 3GPP TS 23.003 [7].  Further details
   about the GSMA role in allocating the IMEI and the IMEI allocation
   guidelines can be found in GSMA PRD DG.06 [8]


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 [5].




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3.  Background

   GSM and UMTS capable mobile devices represent 90% of the mobile
   devices in use worldwide.  GSM and UMTS mobile devices each have an
   IMEI allocated which uniquely identifies the mobile device from all
   other GSM/UMTS mobile devices deployed.  Amongst other things in some
   regulatory jurisdictions the IMEI is used to identify a stolen mobile
   is being used and help to identify the subscription that is using it
   and to prevent its use.  Whilst GSM was originally a circuit switched
   system enhancements such as GPRS (General Packet Radio Service) and
   UMTS have added IP data capabilities which along with the definition
   of the IP Multimedia Subsystem (IMS) has made SIP based calls and IP
   multimedia sessions from mobile devices possible.  The latest
   enhancment known as LTE will introduce even higher data rates and
   dispenses with the circuit switched domain completely meaning that
   with LTE voice calls will need to be conducted using IP and IMS.
   However, the transition to all IP, SIP based IMS networks worldwide
   will take a great many years and mobile devices being mobile will
   need to operate in both IP/SIP/IMS mode and circuit switched mode.
   In fact calls and sessions will need to be handed over between IP/
   SIP/IMS mode and circuit switched mode during a call.  Also as many
   existing GSM and UMTS radio access networks are unable to support IP/
   SIP/IMS based voice services in a commercially acceptable manner some
   sessions may have some media types delivered via IP/IMS
   simultaneously with voice media delivered via circuit switched with
   the same mobile device simultaneously attached via both the IP/SIP/
   IMS domain and the circuit switched domain.  To meet this need 3GPP
   has specified how to maintain session continuity between the IP/SIP/
   IMS domain and the circuit switched domain in 3GPP TS 24.237 [9] and
   how to access IMS hosted services via both the IP/SIP/IMS domain and
   the circuit switched domain in 3GPP TS 24.292 [10].

   In order for the the mobile device to access SIP/IMS services via the
   circuit switched domain 3GPP has defined a MSC (Mobile Switching
   Center) server enhanced for ICS which controls mobile voice call
   setup over the circuit switched radio access while establishing the
   corresponding voice session in the core network using SIP/IMS.  To
   enable this the MSC server enhanced for ICS (IMS centralized
   services) performs SIP registration on behalf of the mobile device
   which may simultaneously also be directly registered with the IP/SIP/
   IMS domain.  The SIP/IMS network needs to be able to identify that
   both of these SIP registrations are from the same UA instance and
   also correctly handle sessions establishment requests addressed using
   GRUUs as defined in RFC 5627 [2] when the mobile device is attached
   using the circuit switched domain.  The only mobile device identifier
   that is transportable using GSM/UMTS/LTE signaling is the IMEI
   therefore the instance-id used by the MSC server enhanced for ICS
   when registering on behalf of the mobile device and the instance-id



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   when the mobile device registers directly needs to be based on the
   IMEI.

   Additionally in order to meet the regulatory requirements to use the
   IMEI to identify a stolen mobile is being used and help to identify
   the subscription that is using it and to prevent its use the same
   IMEI that is obtained from the circuit switched signaling needs to be
   obtainable from SIP signaling.

   3GPP TS 24.237 [9] and 3GPP TS 24.292 [10] already define the use of
   the URN namespace for the GSMA and IMEI as defined in
   draft-montemurro-gsma-imei-urn-06 [3] as the instance-id used by
   mobile devices and the MSC server enhanced for ICS for SIP/IMS
   registrations for these reasons.



4.  User Agent Client Procedures

   A UAC that has an IMEI as defined in 3GPP TS 23.003 [7] SHALL include
   in the "sip.instance" media feature tag the GSMA IMEI URN according
   to the syntax defined in draft-montemurro-gsma-imei-urn-06 [3] when
   performing the registration procedures defined in RFC 5626 [1] or RFC
   5627 [2] or any other procedure requiring including the
   "sip.instance" media feature tag.  The UAC must provide lexically
   equivalent URNs in each registration [1].  Hence, any optional or
   variable components of the URN (e.g., the "vers" and "svn"
   parameters) must be presented with the same values and in the same
   order in every registration as in the first registration.


5.  Security considerations

   In order to protect from tampering the REGISTER requests containing
   the GSMA IMEI URN SHOULD be sent using a security mechanism such as
   TLS [11] (or other security mechanism that provides equivalent levels
   of protection).


6.  Acknowledgements

   The author would like to thank Paul Kyzivat and Dale Worley for
   reviewing this draft and providing their comments.


7.  References





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7.1.  Normative references

   [1]   Jennings, C., Mahy, R., and F. Audet, "Managing Client-
         Initiated Connections in the Session Initiation Protocol
         (SIP)", RFC 5626, October 2009.

   [2]   Rosenberg, J., "Obtaining and Using Globally Routable User
         Agent URIs (GRUUs) in the Session Initiation Protocol (SIP)",
         RFC 5627, October 2009.

   [3]   Montemurro, M., "A Uniform Resource Name Namespace For The GSM
         Association (GSMA) and the International Mobile  station
         Equipment Identity(IMEI), work in progress", Internet
         Draft draft-montemurro-gsma-imei-urn-06, January 2011.

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

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

7.2.  Informative references

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

   [7]   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/>.

   [8]   GSMA Association, "IMEI Allocation and Approval Guidelines",
         PRD DG.06 version 3.6, February 2008,
         <http://gsmworld.com/newsroom/document%2Dlibrary/>.

   [9]   3GPP, "TS 24.237: Mobile radio interface Layer 3 specification;
         Core network protocols; Stage 3 (Release 8)", 3GPP 24.237,
         March 2009,
         <ftp://ftp.3gpp.org/Specs/archive/24_series/24.237/>.

   [10]  3GPP, "TS 24.292: IP Multimedia (IM) Core Network (CN)
         subsystem Centralized Services (ICS); Stage 3 (Release 8)",
         3GPP 24.292, March 2009,
         <ftp://ftp.3gpp.org/Specs/archive/24_series/24.292/>.

   [11]  Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
         RFC 2246, January 1999.






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Author's Address

   Andrew Allen (editor)
   Research in Motion (RIM)
   2550 West Golf Road
   Rolling Meadows, Illinois  60008
   USA

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








































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