Internet DRAFT - draft-boucadair-ipsecme-ipv6-ipv4-codes
draft-boucadair-ipsecme-ipv6-ipv4-codes
Network Working Group M. Boucadair
Internet-Draft Orange
Updates: 7296 (if approved) September 20, 2018
Intended status: Standards Track
Expires: March 24, 2019
IKEv2 Notification Codes for IPv4/IPv6 Coexistence
draft-boucadair-ipsecme-ipv6-ipv4-codes-03
Abstract
This document specifies new IKEv2 notification codes to better manage
IPv4 and IPv6 co-existence.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on March 24, 2019.
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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 . . . . . . . . . . . . . . . . . . . . . 4
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . 5
8.2. 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 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
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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
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.
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 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.
4. 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.
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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
code. If the initiator requests 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.
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 requests both IPv4 and IPv6
addresses/prefixes, the responder replies with IPv4 address(es)
and the IP4_ONLY_SUPPORTED notification code. If the initiator
requests 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 indicates that only a single
address family can be assigned per request, not both. This code
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 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].
5. Security Considerations
This document adheres to the security considerations defined in
[RFC7849].
6. IANA Considerations
This document requests IANA to update the "IKEv2 Notify Message Types
- Error Types" registry available at:
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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]
7. Acknowledgements
Many thanks to Christian Jacquenet for the review.
Thanks to Paul Wouters 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>.
Author's Address
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Mohamed Boucadair
Orange
Rennes 35000
France
Email: mohamed.boucadair@orange.com
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