IKEv2 Notification Status Types for IPv4/IPv6 Coexistence
draft-ietf-ipsecme-ipv6-ipv4-codes-01

Network Working Group                                       M. Boucadair
Internet-Draft                                                    Orange
Updates: 7296 (if approved)                            November 05, 2018
Intended status: Standards Track
Expires: May 9, 2019

       IKEv2 Notification Status Types for IPv4/IPv6 Coexistence
                 draft-ietf-ipsecme-ipv6-ipv4-codes-01

Abstract

   This document specifies new IKEv2 notification status types to better
   manage IPv4 and IPv6 co-existence.

   This document updates RFC7296.

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 https://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 May 9, 2019.

Copyright Notice

   Copyright (c) 2018 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
   (https://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.

Boucadair                  Expires May 9, 2019                  [Page 1]
Internet-Draft            An Update to RFC7296             November 2018

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Why Not INTERNAL_ADDRESS_FAILURE? . . . . . . . . . . . . . .   3
   4.  An Update to RFC7296  . . . . . . . . . . . . . . . . . . . .   3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   As described in [RFC7849], if the subscription data or network
   configuration allows only one IP address family (IPv4 or IPv6), the
   cellular host must not request a second PDP-Context to the same APN
   for the other IP address family.  The Third Generation Partnership
   Project (3GPP) network informs the cellular host about allowed Packet
   Data Protocol (PDP) types by means of Session Management (SM) cause
   codes.  In particular, the following cause codes can be returned:

   o  cause #50 "PDP type IPv4 only allowed": This cause code is used by
      the network to indicate that only PDP type IPv4 is allowed for the
      requested Public Data Network (PDN) connectivity.

   o  cause #51 "PDP type IPv6 only allowed": This cause code is used by
      the network to indicate that only PDP type IPv6 is allowed for the
      requested PDN connectivity.

   o  cause #52 "single address bearers only allowed": This cause code
      is used by the network to indicate that the requested PDN
      connectivity is accepted with the restriction that only single IP
      version bearers are allowed.

   If the requested IPv4v6 PDP-Context is not supported by the network
   but IPv4 and IPv6 PDP types are allowed, then the cellular host will
   be configured with an IPv4 address or an IPv6 prefix by the network.
   It must initiate another PDP-Context activation of the other address
   family in addition to the one already activated for a given Access
   Point Name (APN).  The purpose of initiating a second PDP-Context is
   to achieve dual-stack connectivity by means of two PDP-Contexts.

   According to 3GPP specifications (TS.24302), when the UE attaches the
   network using a WLAN access by means of IKEv2 capabilities [RFC7296],
   there are no equivalent notification codes to inform the User

Boucadair                  Expires May 9, 2019                  [Page 2]
Internet-Draft            An Update to RFC7296             November 2018

   Equipment (UE) why an IP address family is not assigned or whether
   that UE should retry with another address family.

   This document fills that void by introducing new IKEv2 notification
   status types for the sake of deterministic UE behaviors.

   These notification status types are not specific to 3GPP
   architectures, but can be used in other deployment contexts.
   Cellular networks are provided as an illustration example.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119][RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   This document makes use of the terms defined in [RFC7296].  In
   particular, readers should be familiar with "initiator" and
   "responder" terms used in that document.

3.  Why Not INTERNAL_ADDRESS_FAILURE?

   Section 3.15.4 of [RFC7296] defines a generic notification error type
   that is related to a failure to handle an internal address failure.
   That error type does not explicitly allow an initiator to determine
   why a given address family is not assigned, nor whether it should try
   using another address family.  INTERNAL_ADDRESS_FAILURE is a catch-
   all error type when an address-related issue is encountered by an
   IKEv2 responder.

   INTERNAL_ADDRESS_FAILURE does not provide sufficient hints to the
   IKEv2 initiator to adjust its behavior.

4.  An Update to RFC7296

   The following notification status types are defined:

   o  UNSUPPORTED_AF: This status type indicates that the requested
      address family (IPv4 or IPv6) is not supported.  Subsequent
      exchanges with the remote peer MUST NOT include any object of that
      address family.

   o  IP6_ONLY_SUPPORTED: This status type indicates that only IPv6 is
      supported.  Subsequent exchanges with the remote peer MUST NOT
      include any IPv4-related object.

Boucadair                  Expires May 9, 2019                  [Page 3]
Internet-Draft            An Update to RFC7296             November 2018

      Concretely, if the initiator requests both IPv4 and IPv6
      addresses/prefixes, the responder replies with IPv6
      address(es)/prefix(es) and the IP6_ONLY_SUPPORTED notification
      status type.  If the initiator requests only IPv4 address(es) but
      gets the IP6_ONLY_SUPPORTED notification status type from the
      responder, the IPv6-capable initiator should request IPv6
      address(es) only in subsequent requests.

   o  IP4_ONLY_SUPPORTED: This status type indicates that only IPv4 is
      supported.  Subsequent exchanges with the remote peer MUST NOT
      include any IPv6-related object.

      Concretely, if the initiator requests both IPv4 and IPv6
      addresses/prefixes, the responder replies with IPv4 address(es)
      and the IP4_ONLY_SUPPORTED notification status type.  If the
      initiator requests only IPv6 address(es) and gets the
      IP4_ONLY_SUPPORTED notification status type from the responder,
      the IPv4-capable initiator should request IPv4 address(es) only in
      subsequent requests.

   o  SINGLE_AF_SUPPORTED: This status type indicates that only a single
      address family can be assigned per request, not both.  This status
      type is returned when an initiator requested both IPv4 and IPv6
      addresses/prefixes in the same request, but only a single address
      family can be assigned per request by the responder.

      The address family preference is defined by a policy that is local
      to the responder.

      If a responder receives a request for both IPv4 and IPv6 address
      families, it replies with the preferred address family and
      includes SINGLE_AF_SUPPORTED notification status type.  Upon
      receipt of this status type, the initiator MAY re-issue another
      configuration request to ask for an additional address family.

   For other address-related error cases that have not been covered by
   the aforementioned notification status types, the repsonder/initiator
   MUST follow the procedure defined in Section 3.15.4 of [RFC7849].

5.  Security Considerations

   This document adheres to the security considerations defined in
   [RFC7296].

Boucadair                  Expires May 9, 2019                  [Page 4]
Internet-Draft            An Update to RFC7296             November 2018

6.  IANA Considerations

   This document requests IANA to update the "IKEv2 Notify Message Types
   - Status Types" registry available at:
   https://www.iana.org/assignments/ikev2-parameters/
   ikev2-parameters.xhtml with the following status types:

   Value           NOTIFY MESSAGES - STATUS TYPES        Reference
    TBD                     UNSUPPORTED_AF           [This-Document]
    TBD                   IP6_ONLY_SUPPORTED         [This-Document]
    TBD                   IP4_ONLY_SUPPORTED         [This-Document]
    TBD                  SINGLE_AF_SUPPORTED         [This-Document]

7.  Acknowledgements

   Many thanks to Christian Jacquenet for the review.

   Thanks to Paul Wouters, Yaov Nir, Valery Smyslov, and Daniel Migault
   for the comments.

8.  References

8.1.  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,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC7296]  Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
              Kivinen, "Internet Key Exchange Protocol Version 2
              (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
              2014, <https://www.rfc-editor.org/info/rfc7296>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

8.2.  Informative References

   [RFC7849]  Binet, D., Boucadair, M., Vizdal, A., Chen, G., Heatley,
              N., Chandler, R., Michaud, D., Lopez, D., and W. Haeffner,
              "An IPv6 Profile for 3GPP Mobile Devices", RFC 7849,
              DOI 10.17487/RFC7849, May 2016,
              <https://www.rfc-editor.org/info/rfc7849>.

Boucadair                  Expires May 9, 2019                  [Page 5]
Internet-Draft            An Update to RFC7296             November 2018

Author's Address

   Mohamed Boucadair
   Orange
   Rennes  35000
   France

   Email: mohamed.boucadair@orange.com

Boucadair                  Expires May 9, 2019                  [Page 6]