Dispatch Working Group R. Atarius, Ed. Internet-Draft Qualcomm Technologies, Inc. Intended status: Informational December 17, 2014 Expires: June 20, 2015 Using the Mobile Equipment Identity (MEID) Uniform Resource Name (URN) as an Instance ID draft-atarius-dispatch-meid-urn-as-instanceid-01 Abstract This specification specifies how the Uniform Resource Name (URN) namespace reserved for the Third Generation Partnership Project 2 (3GPP2) identities and its Namespace Specific String (NSS) for the Mobile Equipment Identity (MEID) can be used as an instance-id. Its purpose is to fulfill the requirements for defining how a specific URN needs to be constructed and used in the "+sip.instance" Contact header field parameter for outbound behavior. 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 working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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 June 20, 2015. Copyright Notice Copyright (c) 2014 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 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must Atarius Expires June 20, 2015 [Page 1] Internet-Draft Using MEID URN as an Instance ID December 2014 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. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Background . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. 3GPP2 Use Cases . . . . . . . . . . . . . . . . . . . . . . . 4 5. User Agent Client Procedures . . . . . . . . . . . . . . . . 4 6. User Agent Server Procedures . . . . . . . . . . . . . . . . 5 7. 3GPP2 SIP Registrar Procedures . . . . . . . . . . . . . . . 5 8. IANA considerations . . . . . . . . . . . . . . . . . . . . . 6 9. Security considerations . . . . . . . . . . . . . . . . . . . 6 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 11.1. Normative references . . . . . . . . . . . . . . . . . . 7 11.2. Informative references . . . . . . . . . . . . . . . . . 8 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction This specification specifies how the URN namespace reserved for 3GPP2 identities and its NSS for the MEID as specified in draft-atarius- dispatch-meid-urn [8] can be used as an instance-id as specified in RFC 5626 [2] and also as used by RFC 5627 [3]. RFC 5626 [2] specifies the "+sip.instance" Contact header field parameter that contains a URN as specified in RFC 2141 [4]. The instance-id uniquely identifies a specific User Agent (UA) instance. This instance-id is used as specified in RFC 5626 [2] so that the Session Initiation Protocol (SIP) registrar (as specified in RFC 3261 [1]) can recognize that the contacts from multiple registrations correspond to the same UA. The instance-id is also used as specified by RFC 5627 [3] 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 [2] requires that a UA SHOULD create a Universally Unique Identifier (UUID) URN as specified in RFC 4122 [7] as its instance-id but allows for the possibility to use other URN schemes. "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 3GPP2 MEID URN is used in the "+sip.instance" Contact header field parameter for outbound behavior Atarius Expires June 20, 2015 [Page 2] Internet-Draft Using MEID URN as an Instance ID December 2014 and draft-atarius-dispatch-meid-urn [8] specifies how the 3GPP2 MEID URN is constructed. The 3GPP2 MEID is a URN for the MEID a globally unique identifier that identifies mobile devices used in the 3GPP2 networks. The MEID allocation is managed by the 3GPP2 to ensure that the MEID values are globally unique. Details of the formatting of the MEID as a URN are specified in draft-atarius-dispatch-meid-urn [8] and the definition of the MEID is contained in 3GPP2 S.R0048-A [12]. 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 RFC 2119 [5]. 3. Background The mobile communication has been rapidly improved from low bit rate circuit switched system to the higher data rate packet switched system. The packet switched system has added mobile capability of Internet Protocol (IP) connectivity and thereby the IP Multimedia Subsystem (IMS) have made SIP based calls and IP multimedia sessions from mobile devices possible. 3GPP2 defines High Rate Packet Data (HRPD) with high data rates and dispenses with the 1x Circuit Switched (1xCS) infrastructure. This means that with HRPD networks, 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 will need to operate in both IP/SIP/IMS mode and circuit switched mode. This means that calls and sessions will need to be handed over between IP/SIP/IMS mode and circuit switched mode mid-call or mid- session. To achieve this the mobile device needs to be simultaneously attached via both the IP/SIP/IMS domain and the circuit switched domain. To meet this need 3GPP2 has specified how to maintain voice session continuity between the IP/SIP/IMS domain and the circuit switched domain in 3GPP2 S.X0042-B [13]. In order for the mobile device to access SIP/IMS voice service via the circuit switched domain 3GPP2 has specified that Mobile Switching Center (MSC) server either via IMS Media Gateway Control Function (MGCF) or directly, if enhanced by SIP interface, 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 mobile device MUST be identified Atarius Expires June 20, 2015 [Page 3] Internet-Draft Using MEID URN as an Instance ID December 2014 in both 1xCS and IP/SIP/IMS domains. The only mobile device identifier that is transportable using 1xCS signaling is the MEID therefore the instance-id included by the MGCF or the MSC server, and the instance-id directly included by the mobile device both need to be based on the MEID. Additionally in order to meet the above requirements, the same MEID that is obtained from the circuit switched signaling by the MSC server needs to be obtainable from SIP signaling so that it can be determined that both the SIP signaling and circuit switched signaling originate from the same mobile device. 4. 3GPP2 Use Cases 1. The mobile device includes its MEID in the SIP REGISTER request so that the SIP registrar can perform a check of the Equipment Identity Register (EIR) to verify if this mobile device is allowed or barred from accessing the network for non-emergency services (e.g., because it has been stolen). If the mobile device is not allowed to access the network for non-emergency services the SIP registrar can reject the registration. Thus a barred mobile device is prevented from accesssing the network for non-emergency services. 2. The mobile device includes its MEID in SIP INVITE requests used to establish emergency sessions. This is so that the Public Safety Answering Point (PSAP) can obtain the MEID of the mobile device for identification purposes if required by regulations. 3. The inclusion by the mobile device of its MEID in SIP INVITE requests used to establish emergency sessions is also used in the cases of unauthenticated emergency sessions to enable the network to identify the mobile device. This is especially important if the unauthenticated emergency session is handed over from the packet switched domain to the circuit switched domain. In this scenario the MEID is the only identifier that is common to both domains. The Emergency Access Transfer Function (EATF) which coordinates the call transfer between the domains, can thus use the MEID to identify that the circuit switched call is from the same mobile device that was in the emergency session in the packet switched domain. 5. User Agent Client Procedures A single mode Third Generation Partnership Project (3GPP) User Agent Client (UAC) which uses only 3GPP technology to transmits and receive voice or data, or a dual mode 3GPP/3GPP2 UAC which uses either 3GPP or 3GPP2 technology to transmit and receive voice or data has an International Mobile station Equipment Identity (IMEI) as specified in 3GPP TS 23.003 [14]. A single mode 3GPP2 UAC which uses only Atarius Expires June 20, 2015 [Page 4] Internet-Draft Using MEID URN as an Instance ID December 2014 3GPP2 technology to transmit and receive voice or data has however an MEID as specified in 3GPP2 S.R0048-A [12]. The single mode 3GPP2 UAC that is registering with a 3GPP2 IMS network MUST include in the "sip.instance" media feature tag the 3GPP2 MEID URN according to the syntax specified in draft-atarius-dispatch-meid-urn [8] when performing the registration procedures specified in RFC 5626 [2] or RFC 5627 [3] or any other procedure requiring the inclusion of the "sip.instance" media feature tag. Note that the syntax of IMEI URN is specified in RFC 7254 [10]. A UAC MUST NOT use the 3GPP2 MEID URN as an instance-id except when registering with a 3GPP2 IMS network. When a UAC is operating in IMS mode it will obtain the domain of the carrier's IMS network to register with, from the Universal Integrated Circuit Card (UICC), preconfiguration, or the network at the time of establishing the Packet Data Protocol (PDP) context. These three methods are carrier specific and are only performed by the carrier. The UAC will also obtain the address of the IMS edge proxy to send the REGISTER request containing the MEID using information elelments in the Attach response when it attempts to connect to the carriers packet data network. When registering with a non-3GPP or non-3GPP2 IMS network a UAC SHOULD use a Universally Unique Identifier (UUID) as an instance- id as specified in RFC 5626 [2]. A UAC MUST NOT include the "sip.instance" media feature tag containing the 3GPP2 MEID URN in the Contact header field of non- REGISTER requests except when the request is related to an emergency session. Regulatory requirements can require the MEID to be provided to the PSAP. Any future exceptions to this prohibition require an RFC that addresses how privacy is not violated by such a usage. 6. User Agent Server Procedures A User Agent Server (UAS) MUST NOT include its "sip.instance" media feature tag containing the 3GPP2 MEID URN in the Contact header field of responses except when the response is related to an emergency session. Regulatory requirements can require the MEID to be provided to the PSAP. Any future exceptions to this prohibition require an RFC that addresses how privacy is not violated by such a usage. 7. 3GPP2 SIP Registrar Procedures In 3GPP2 IMS when the SIP Registrar receives in the Contact header field a "sip.instance" media feature tag containing the 3GPP2 MEID URN according to the syntax specified in draft-atarius-dispatch-meid- urn [8] the SIP registrar follows the procedures specified in RFC 5626 [2]. The MEID URN MAY be validated as described in the draft- atarius-dispatch-meid-urn [8]. If the UA indicates that it supports Atarius Expires June 20, 2015 [Page 5] Internet-Draft Using MEID URN as an Instance ID December 2014 the extension in RFC 5627 [3] and the SIP Registrar allocates a GRUU according to the procedures specified in RFC 5627 [3] the instance-id MUST be obfuscated when creating the "gr" parameter in order not to reveal the MEID to other UAs when the public GRUU is included in non- REGISTER requests and responses. 3GPP TS 24.229 [9] subclause 5.4.7A.2 specifies the mechanism for obfuscating the MEID when creating the "gr" parameter. 8. IANA considerations This document defines no items requiring action by IANA. 9. Security considerations Since MEIDs like other formats of instance-ids can be correlated to a user, they are personally identifiable information and MUST be treated as such. In particular, the "sip.instance" media feature tag containing the 3GPP2 MEID URN MUST NOT be included in requests or responses intended to convey any level of anonymity, as this could violate the users privacy. RFC 5626 [2] states "One case where a UA could prefer to omit the "sip.instance" media feature tag is when it is making an anonymous request or some other privacy concern requires that the UA not reveal its identity". The same concerns apply when using the 3GPP2 MEID URN as an instance-id. Publication of the 3GPP2 MEID URN to networks that the UA is not attached to or the UA does not have a service relationship with is a security breach and the "sip.instance" media feature tag MUST NOT be forwarded by the service provider's network elements when forwarding requests or responses towards the destination UA. Additionally, an instance-id containing the 3GPP2 MEID URN identifies a mobile device and not a user. The instance-id containing the 3GPP2 MEID URN MUST NOT be used alone as an address for a user or as an identification credential for a user. The GRUU mechanism specified in RFC 5627 [3] provides a means to create URIs that address the user at a specific device or User Agent. Entities that log the instance-id, need to protect them as personally identifiable information. Regulatory requirements can require carriers to log SIP MEIDs. In order to protect the "sip.instance" media feature tag containing the 3GPP2 MEID URN from being tampered with, those REGISTER requests containing the 3GPP2 MEID URN MUST be sent using a security mechanism such as Transport Layer Security (TLS) as specified in RFC 4346 [6] or any other security mechanism that provides equivalent levels of protection such as hop-by-hop security based upon IP Security (IPSec). Atarius Expires June 20, 2015 [Page 6] Internet-Draft Using MEID URN as an Instance ID December 2014 10. Acknowledgements This document draws heavily on draft-atarius-dispatch-meid-urn [8] and also on the style and structure used in RFC 7255 [11]. The author thanks for the detailed comments, provided by Andrew Allen. 11. References 11.1. Normative references [1] 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. [2] Jennings, C., Mahy, R., and F. Audet, "Managing Client- Initiated Connections in the Session Initiation Protocol (SIP)", RFC 5626, October 2009. [3] Rosenberg, J., "Obtaining and Using Globally Routable User Agent URIs (GRUUs) in the Session Initiation Protocol (SIP)", RFC 5627, October 2009. [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. [6] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.1", RFC 4346, April 2006. [7] Leach, P., Mealling, M., and R. Salz, "A Universally Unique IDentifier (UUID) URN Namespace", RFC 4122, July 2005. [8] Atarius, R., "A Uniform Resource Name Namespace for the Device Identity and the Mobile Equipment Identity (MEID)", Internet Draft draft-atarius-dispatch-meid-urn, October 2014. [9] 3GPP, "TS 24.229: IP multimedia call control protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP); Stage 3 (Release 10)", 3GPP 24.229, September 2013, . Atarius Expires June 20, 2015 [Page 7] Internet-Draft Using MEID URN as an Instance ID December 2014 11.2. Informative references [10] Montemurro, M., 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, May 2014. [11] Allen, A., "Using the International Mobile station Equipment Identity (IMEI) Uniform Resource Name (URN) as an Instance ID", RFC 7255, May 2014. [12] 3GPP2, "S.R0048-A: 3G Mobile Equipment Identifier (MEID) - Stage 1, Version 4.0", 3GPP2 S.R0048-A 4.0, June 2005. [13] 3GPP2, "S.X0042-B: Voice Call Continuity between IMS and Circuit Switched Systems - Version 1.0", 3GPP2 S.X0042-B 1.0, December 2013. [14] 3GPP, , "TS 23.003: Numbering, addressing and identification (Release 8)", 3GPP 23.003, September 2013, . Author's Address Roozbeh Atarius (editor) Qualcomm Technologies, Inc. 5775 Morehouse Drive San Diego, CA 92121 USA Phone: +1 858 845 1341 Email: ratarius@qti.qualcomm.com Atarius Expires June 20, 2015 [Page 8]