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Updates to Private Header (P-Header) Extension Usage in Session Initiation Protocol (SIP) Requests/Responses
draft-holmberg-dispatch-rfc7315-updates-07

The information below is for an old version of the document.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 7976.
Authors Christer Holmberg , Nevenka Biondic , Gonzalo Salgueiro
Last updated 2016-06-28 (Latest revision 2016-06-22)
RFC stream Internet Engineering Task Force (IETF)
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Stream WG state (None)
Document shepherd Jean Mahoney
Shepherd write-up Show Last changed 2016-05-18
IESG IESG state Became RFC 7976 (Informational)
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Responsible AD Ben Campbell
Send notices to (None)
IANA IANA review state IANA OK - No Actions Needed
draft-holmberg-dispatch-rfc7315-updates-07
Network Working Group                                        C. Holmberg
Internet-Draft                                                N. Biondic
Updates: 7315 (if approved)                                     Ericsson
Intended status: Informational                              G. Salgueiro
Expires: December 24, 2016                                         Cisco
                                                           June 22, 2016

    Updates to Private Header (P-Header) Extension Usage in Session
              Initiation Protocol (SIP) Requests/Responses
               draft-holmberg-dispatch-rfc7315-updates-07

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 December 24, 2016.

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   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  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     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

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   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 3455:

   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-

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      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 when triggered by a SIP 2xx response.

   o  P-Charging-Vector: Add statement that the header field can appear
      in the SIP ACK method when triggered by a SIP 2xx response.

   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

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   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 non-2xx responses.

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 SIP non-2xx responses.

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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 non-100 responses, except in CANCEL methods, CANCEL responses
   and ACK methods triggered by non-2xx responses. The P-Charging-Vector
   header field can appear in all SIP methods and non-100 responses,
   except in CANCEL methods, CANCEL responses and ACK methods triggered
   by non-2xx responses. The P-Charging-Function-Addresses header field
   can appear in all SIP methods and non-100 responses, except in ACK
   and CANCEL methods and CANCEL responses.

5.  Security Considerations

   The security considerations for these 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 the
   security considerations and assumptions (e.g. regarding only sending
   information to trusted entities) also to those messages.  In
   addition, this specification also disallow some header fields to be
   present in message 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,

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   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).  This document adds the ability to include P-
   Access-Network-Info in ACK requests.  As documented in [RFC7315], P-
   Access-Network-Info may include privacy sensitive information,
   including the user's location.  The security and privacy
   considerations for P-Access-Network-Info in ACK requests are similar
   to those for the other SIP requests discussed in [RFC7315].

6.  IANA Considerations

   This document makes no requests from IANA.

7.  Acknowledgments

   Thanks to Paul Kyzivat, Jean Mahoney, Ben Campbell and Adam Roach 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-06

   o  Changes based on AD comments from Ben Campbell.

   o  - Additional text added to Security Considerations.

   Changes from draft-holmberg-dispatch-rfc7315-updates-05

   o  Editorial changes based on comments from Adam Roach.

   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.

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   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,
              <http://www.rfc-editor.org/info/rfc2119>.

   [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,
              <http://www.rfc-editor.org/info/rfc3261>.

   [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, <http://www.rfc-editor.org/info/rfc7315>.

   [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,
              <http://www.rfc-editor.org/info/rfc3455>.

Authors' Addresses

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   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

   Gonzalo Salgueiro
   Cisco Systems, Inc.
   7200-12 Kit Creek Road
   Research Triangle Park, NC  27709
   US

   Email: gsalguei@cisco.com

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