IKEv2 Notification Codes for IPv4/IPv6 Coexistence
draft-boucadair-ipsecme-ipv6-ipv4-codes-00

Versions: 00                                                            
Network Working Group                                       M. Boucadair
Internet-Draft                                                    Orange
Updates: 7296 (if approved)                              October 6, 2017
Intended status: Standards Track
Expires: April 9, 2018


           IKEv2 Notification Codes for IPv4/IPv6 Coexistence
               draft-boucadair-ipsecme-ipv6-ipv4-codes-00

Abstract

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

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
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   This Internet-Draft will expire on April 9, 2018.

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Table of Contents

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

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 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 UE why an IP




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   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
   codes for the sake of deterministic UE behaviors.

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

   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.

2.  Why Not INTERNAL_ADDRESS_FAILURE?

   Section 3.15.4 of [RFC7296] defines a generic notification code that
   is related to a failure to handle an internal address failure.  That
   code 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 code
   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.

3.  An Update to RFC7296

   The following notification codes are defined:

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

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





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

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

   o  SINGLE_AF_SUPPORTED: This code is returned as a response to a
      request, that includes both IPv4 and IPv6 address(es)/prefixe(e)s,
      to indicate that only a single address family can be assigned per
      request.  The address family to be used is defined by a policy
      that is local to the responder.  If a responder received a request
      for both IPv4 and IPv6 address families, it replies with the
      preferred address family and includes SINGLE_AF_SUPPORTED
      notification code.  Upon receipt of this code, 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 codes, the repsonder/Initiator MUST
   follow the procedure defined in Section 3.15.4 of [RFC7849].

4.  Security Considerations

   This document adheres to the security considerations defined in
   [RFC7849].

5.  IANA Considerations

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

   Value           NOTIFY MESSAGES - ERROR 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]








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6.  Acknowledgements

   Many thanks to Christian Jacquenet for the review.

7.  References

7.1.  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>.

7.2.  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>.

Author's Address

   Mohamed Boucadair
   Orange
   Rennes  35000
   France

   Email: mohamed.boucadair@orange.com

















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