Internet Engineering Task Force (IETF)                       C. Holmberg
Request for Comments: 7913                                      Ericsson
Updates: 7315                                                  June 2016
Category: Informational
ISSN: 2070-1721


                   P-Access-Network-Info ABNF Update

Abstract

   This document updates RFC 7315, by modifying the extension-access-
   info part of the P-Access-Network-Info header field Augmented Backus-
   Naur Form (ABNF), and by adding the following 'access-info' header
   field parameter values to the list of 'access-info' header field
   parameter values in the ABNF: 'operator-specific-GI' and
   'utran-sai-3gpp'.  The values are defined in the ABNF but are not
   included in the list.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7913.

Copyright Notice

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   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Update to RFC 7315  . . . . . . . . . . . . . . . . . . . . .   3
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   4.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   [RFC7315] defines the Session Initiation Protocol (SIP) [RFC3261]
   P-Access-Network-Info header field.

   The header field syntax contains an 'access-info' header field
   parameter, with a set of pre-defined values.  Most pre-defined values
   follow the 'generic-param' rule [RFC3261].  However, currently the
   Augmented Backus-Naur Form (ABNF) [RFC5234] in [RFC7315] requires new
   values to follow the 'gen-value' rule [RFC3261], which is more
   restrictive than 'generic-param'.  There is no justification for the
   restriction, and new values have already been defined following the
   'generic-param' rule.

   The ABNF also defines the following 'access-info' header field
   parameter values: 'operator-specific-GI' and 'utran-sai-3gpp'.
   However, the values are not included in the list of 'access-info'
   values.

   This document updates Section 5.4 of [RFC7315], by modifying the
   extension-access-info part of the P-Access-Network-Info header field
   ABNF.

   As the P-Access-Network-Info header field is mainly used in networks
   defined by the 3rd-Generation Partnership Project (3GPP), where new
   values following the 'generic-param' rule have been defined
   [TS.3GPP.24.229], the update is not considered to cause issues with
   backward compatibility.

2.  Update to RFC 7315

   This section updates the ABNF defined in Section 5.4 of RFC 7315, as
   described below:

  Old syntax:

      access-info            = cgi-3gpp / utran-cell-id-3gpp /
                               dsl-location / i-wlan-node-id /
                               ci-3gpp2 / eth-location /
                               ci-3gpp2-femto / fiber-location /
                               np / gstn-location /local-time-zone /
                               dvb-rcs2-node-id / extension-access-info
      np                     = "network-provided"
      extension-access-info  = gen-value

  New syntax:

      access-info            = cgi-3gpp / utran-cell-id-3gpp /
                               dsl-location / i-wlan-node-id /
                               ci-3gpp2 / eth-location /
                               ci-3gpp2-femto / fiber-location /
                               np / gstn-location /local-time-zone /
                               dvb-rcs2-node-id / operator-specific-GI /
                               utran-sai-3gpp / extension-access-info
      np                     = "network-provided"
      extension-access-info  = generic-param

3.  Security Considerations

   The security considerations for the P-Access-Network-Info header
   field are defined in [RFC7315].  The ABNF update defined in this
   document does not impact the security considerations.

4.  Normative References

   [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>.

   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234,
              DOI 10.17487/RFC5234, January 2008,
              <http://www.rfc-editor.org/info/rfc5234>.

   [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 13.5.1, March
              2016, <http://www.3gpp.org/ftp/Specs/html-info/24229.htm>.

Acknowledgments

   Thanks to Ben Campbell, Cullen Jennings, Gonzalo Salgueiro, Jean
   Mahoney, Menachem Dodge, Olafur Gudmundsson, Paul Kyzivat, and the
   3GPP community for providing guidance, input, and comments on the
   document.

Author's Address

   Christer Holmberg
   Ericsson
   Hirsalantie 11
   Jorvas  02420
   Finland

   Email: christer.holmberg@ericsson.com