Network Working Group C. Holmberg Internet-Draft N. Biondic Updates: 7315 (if approved) Ericsson Intended status: Informational G. Salgueiro Expires: August 8, 2016 Cisco February 5, 2016 Updates to Private Header (P-Header) Extension Usage in Session Initiation Protocol (SIP) Requests/Responses draft-holmberg-dispatch-rfc7315-updates-05 Abstract The 3rd-Generation Partnership Project 3GPP has identified cases where different SIP private header extensions referred to as P- header fields, defined in RFC 7315, need to be included in SIP requests and responses currently not allowed according to RFC 7315. This document updates RFC 7315, in order to allow inclusion of the affected P- header fields in such requests and responses. This document also makes updates for RFC 7315 in order to fix misalignments that occurred when RFC 3455 was updated and obsoleted by RFC 7315. 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 August 8, 2016. Copyright Notice Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved. Holmberg, et al. Expires August 8, 2016 [Page 1] Internet-Draft 7315 Updates February 2016 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 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. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Misalignments and 3GPP use-cases . . . . . . . . . . . . . . 3 3.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.2. Misalignments . . . . . . . . . . . . . . . . . . . . . . 3 3.3. 3GPP Use-cases . . . . . . . . . . . . . . . . . . . . . 4 3.3.1. General . . . . . . . . . . . . . . . . . . . . . . . 4 3.3.2. P-Access-Network-Info . . . . . . . . . . . . . . . . 4 3.3.3. P-Charging-Vector . . . . . . . . . . . . . . . . . . 5 4. Updates to RFC 7315 . . . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7 8. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 7 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 9.1. Normative References . . . . . . . . . . . . . . . . . . 7 9.2. Informative References . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction The 3rd-Generation Partnership Project (3GPP) has identified cases where different Session Initiation Protocol (SIP) [RFC3261] private header extensions referred to as P- header fields, defined in RFC 7315 [RFC7315], need to be included in SIP requests and responses currently not allowed according to RFC 7315. This document updates RFC 7315, in order to allow inclusion of the affected P- header fields in such requests and responses. This document also makes updates for RFC 7315 in order to fix misalignments that occurred when RFC 3455 [RFC3455] was updated and obsoleted by RFC 7315. As the P- header fields are mainly used in (and in most cases, only defined for) networks defined by the 3rd-Generation Partnership Project (3GPP), where the updates defined in this document are Holmberg, et al. Expires August 8, 2016 [Page 2] Internet-Draft 7315 Updates February 2016 already defined [TS.3GPP.24.229], the updates are not seen to cause backward compatibility concerns. 2. Conventions 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 [RFC2119]. 3. Misalignments and 3GPP use-cases 3.1. General RFC 7315 contains contradicting statements regarding the usage of SIP P- header fields in SIP requests and responses, which leave the presence of the SIP P- header fields in the SIP requests and responses open to interpretation, and different implementations. Statements in section 5.7 are not aligned with the definitions and usage of the SIP P- header fields specified in section 4. This section describes the misalignments that occurred when RFC 3455 was updated and obsoleted by RFC 7315, and how they are fixed. NOTE: In the case of the P-Called-Party-ID header field, allowing it in PUBLISH requests was deliberately done in RFC 7315. It will therefore not be considered a misalignment. Since RFC 7315 was published, 3GPP defined new use-cases that require the RFC to be updated. This section describes the 3GPP use-cases behind the updates, and the updates needed to RFC 7315 in order to support the use-cases. Section 4 updates RFC 7315, based on the misalignments and 3GPP use- cases. 3.2. Misalignments The following updates are needed in order to fix the misalignments between RFC 7315 and RFC 3245: o P-Associated-URI: Remove statement that the header field can appear in the SIP REGISTER method. o P-Called-Party-ID: Delete statement that the header field can appear in SIP responses. Add statement that the P-Called-Party-ID header field can appear in the SIP REFER method. o P-Visited-Network-ID: Delete statement that the header field can appear in SIP responses. Add statement that the P-Visited- Holmberg, et al. Expires August 8, 2016 [Page 3] Internet-Draft 7315 Updates February 2016 Network-ID header field cannot appear in the SIP NOTIFY, PRACK, INFO and UPDATE methods. o P-Access-Network-Info: Add statement that header field can appear in SIP responses. o P-Charging-Vector: Add statement that the header field can appear in SIP responses. Add statement that the header field can not appear in the SIP ACK method. o P-Charging-Function-Addresses: Add statement that the P-Charging- Function-Addresses header field can appear in SIP responses. 3.3. 3GPP Use-cases 3.3.1. General The following updates are needed in order to implement the 3GPP use- cases: o P-Access-Network-Info: Add statement that the header field can appear in the SIP ACK method. o P-Charging-Vector: Add statement that the header field can appear in the SIP ACK method. This following sections describe, for individual P- header fields, the 3GPP use-cases that are base for the updates. 3.3.2. P-Access-Network-Info The P-Access-Network-Info header field may contain the Network provided Location information (NPLI). The Network Provided Location Information (NPLI) is described in 3GPP TS 23.228. A proxy in possession of appropriate information about the access technology might insert a P-Access-Network-Info header field with its own values. Such values are identified by the string "network- provided" defined in RFC 7315. Based on operator policy and/or roaming agreement, local time of visited network may be included. The CDRs generated within IMS have to contain the NPLI in order to guarantee correct billing. When an IMS Session is modified the NPLI also needs to be stored as the location of the user at the time when the session is modified may generate a charging event. In case of a session modification event at IMS, the NPLI needs to be provided: o when the bearer establishment is triggered, or Holmberg, et al. Expires August 8, 2016 [Page 4] Internet-Draft 7315 Updates February 2016 o at session release when the bearer deactivation is triggered, or o when the bearer modification is triggered e.g. QoS modification for the use of newly negotiated codec. In some scenarios, the bearer modification may be triggered by the proxy upon reception of an SDP answer within SIP 2xx response to the SIP INVITE request. In such case the NPLI needs to be provided within the SIP ACK request. However, RFC 7315 does not allow the usage of the P-Access-Network-Info header field in SIP ACK request. Upon reception of the SDP answer within SIP 2xx response on the SIP INVITE request a proxy may initiate procedures to obtain the NPLI and MAY include the P-Access-Network-Info header field with the NPLI in the SIP ACK request. The P-Access-Network-Info header field shall not be included in SIP ACK requests triggered by a 3xx-6xx response. 3.3.3. P-Charging-Vector RFC 7315 defines an Inter Operator Identifier (IOI) to enable different operators involved in a SIP dialog or a transaction outside a dialog to identify each other by exchanging operator identification information within the P-Charging-Vector header field. In the interconnection scenarios in multi operator environments, where one or more transit operators are between the originating and terminating operator, the identities of the involved transit operators are represented by a transit-ioi parameter of the P- Charging-Vector header field. Transit operators can be selected independently for each SIP method and direction of request. A transit network will only have knowledge of an individual SIP request and transit network selection will be an independent decision for each request and could be made based on load, cost, percentage, time of day, and more. For this reason, it is necessary that the P-Charging-Vector header field, which carries the transit IOI information, is included in each SIP request and response. However, RFC 7315 does not allow the usage of the P-Charging- Vector header field in SIP ACK request. A SIP proxy that supports this extension and receives the SIP ACK request MAY include a P-Charging-Vector header field in the SIP ACK request. The P-Charging-Vector header field shall not be included in SIP ACK requests triggered by a 3xx-6xx response. Holmberg, et al. Expires August 8, 2016 [Page 5] Internet-Draft 7315 Updates February 2016 4. Updates to RFC 7315 This section implements the update to section 5.7 of RFC 7315, in order to implement the misalignment fixes and the 3GPP requirements described in Section 3. Old text: The P-Associated-URI header field can appear in SIP REGISTER method and 2xx resonses. The P-Called-Party-ID header field can appear in SIP INVITE, OPTIONS, PUBLISH, SUBSCRIBE, and MESSAGE methods and all responses. The P-Visited-Network-ID header field can appear in all SIP methods except ACK, BYE, and CANCEL and all responses. The P-Access-Network-Info header field can appear in all SIP methods except ACK and CANCEL. The P-Charging-Vector header field can appear in all SIP methods except CANCEL. The P-Charging-Function-Addresses header field can appear in all SIP methods except ACK and CANCEL. New text: The P-Associated-URI header field can appear in SIP REGISTER 2xx responses. The P-Called-Party-ID header field can appear in SIP INVITE, OPTIONS, PUBLISH, REFER, SUBSCRIBE, and MESSAGE methods. The P-Visited-Network-ID header field can appear in all SIP methods except ACK, BYE, CANCEL, NOTIFY, PRACK, INFO and UPDATE. The P-Access-Network-Info header field can appear in all SIP methods and responses, except in CANCEL methods and CANCEL responses. The P-Charging-Vector header field can appear in all SIP methods and responses, except in CANCEL methods and CANCEL responses. The P-Charging-Function-Addresses header field can appear in all SIP methods and responses, except in ACK and CANCEL methods and CANCEL responses. 5. Security Considerations The security considerations for P- header fields are defined in [RFC7315]. This specification allows some header fields to be present in messages where they were previously not allowed, and disallow some header fields to be present in messages where they were previously allowed. That does not cause any security issues, but implementations need to be aware that implementations may not have been updated according to this document, and take proper actions if a header field occur, or does not occur, in a message where it should occur (or occurs in a message where it should not occur). Holmberg, et al. Expires August 8, 2016 [Page 6] Internet-Draft 7315 Updates February 2016 6. IANA Considerations This document makes no requests from IANA. 7. Acknowledgments Thanks to Paul Kyzivat, Jean Mahoney and Ben Campbell for providing comments on the draft. 8. Change Log [RFC EDITOR NOTE: Please remove this section when publishing] Changes from draft-holmberg-dispatch-rfc7315-updates-04 o - Errata removed. All changes defined as RFC 7315 updates. o - Title changed. o - Text added to the Security Considerations. Changes from draft-holmberg-dispatch-rfc7315-updates-03 o - Minor editorial corrections. Changes from draft-holmberg-dispatch-rfc7315-updates-02 o - Justification text for P-Charging-Vector update added. Changes from draft-holmberg-dispatch-rfc7315-updates-01 o - Justification text for P-Access-Network-Info update added. Changes from draft-holmberg-dispatch-rfc7315-updates-00 o - Title corrected. 9. References 9.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . Holmberg, et al. Expires August 8, 2016 [Page 7] Internet-Draft 7315 Updates February 2016 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, DOI 10.17487/RFC3261, June 2002, . [RFC7315] Jesske, R., Drage, K., and C. Holmberg, "Private Header (P-Header) Extensions to the Session Initiation Protocol (SIP) for the 3GPP", RFC 7315, DOI 10.17487/RFC7315, July 2014, . [TS.3GPP.24.229] 3GPP, "IP multimedia call control protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP);Stage 3", 3GPP TS 24.229 13.3.1, September 2015. 9.2. Informative References [RFC3455] Garcia-Martin, M., Henrikson, E., and D. Mills, "Private Header (P-Header) Extensions to the Session Initiation Protocol (SIP) for the 3rd-Generation Partnership Project (3GPP)", RFC 3455, DOI 10.17487/RFC3455, January 2003, . Authors' Addresses Christer Holmberg Ericsson Hirsalantie 11 Jorvas 02420 Finland Email: christer.holmberg@ericsson.com Nevenka Biondic Ericsson Krapinska 45 Zagreb 10002 Croatia Email: nevenka.biondic@ericsson.com Holmberg, et al. Expires August 8, 2016 [Page 8] Internet-Draft 7315 Updates February 2016 Gonzalo Salgueiro Cisco Systems, Inc. 7200-12 Kit Creek Road Research Triangle Park, NC 27709 US Email: gsalguei@cisco.com Holmberg, et al. Expires August 8, 2016 [Page 9]