Softwire WG J. Qin
Internet-Draft ZTE
Intended status: Standards Track M. Boucadair
Expires: May 3, 2012 France Telecom
T. Tsou
Huawei Technologies (USA)
October 31, 2011
DHCPv6 Options for IPv6 DS-Lite Multicast Prefix
draft-qin-softwire-multicast-prefix-option-01
Abstract
This document defines Dynamic Host Configuration Protocol version 6
(DHCPv6) Options for multicast transition solutions, aiming to convey
the IPv6 prefixes to be used to build unicast and multicast IPv4-
embedded IPv6 addresses.
These options can be in particular used in the context of DS-Lite,
Stateless A+P and other IPv4-IPv6 interconnection techniques.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on May 3, 2012.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
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publication of this document. Please review these documents
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carefully, as they describe your rights and restrictions with respect
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. PREFIX64 DHCPv6 Option . . . . . . . . . . . . . . . . . . . . 4
3.1. Option Format . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. M_PREFIX64 Sub-option . . . . . . . . . . . . . . . . . . . 4
3.3. U_PREFIX64 Sub-option . . . . . . . . . . . . . . . . . . . 5
4. Client Behaviour . . . . . . . . . . . . . . . . . . . . . . . 6
5. Server Behaviour . . . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1. Normative References . . . . . . . . . . . . . . . . . . . 8
9.2. Informative References . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
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1. Introduction
[I-D.ietf-softwire-dslite-multicast] and several other solutions
(e.g., [I-D.ietf-softwire-mesh-multicast],
[I-D.venaas-behave-mcast46], etc.) are proposed for the delivery of
multicast services in the context of transition to IPv6. Even these
solutions may have different applicable use cases, they all use
specific IPv6 addresses to embed IPv4 addresses, for both the
multicast group addresses
[I-D.boucadair-behave-64-multicast-address-format], and the multicast
source addresses [RFC6052].
This document defines DHCPv6 options [RFC3315] to convey the IPv6
prefixes (a.k.a., PREFIX64) to be used for constructing these IPv4-
embedded IPv6 addresses.
These options can be in particular used in the context of DS-Lite
[RFC6333], Stateless A+P [RFC6346] and other IPv4-IPv6
interconnection techniques.
1.1. Requirements Language
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 RFC 2119 [RFC2119].
2. Terminology
This document makes use of the following terms:
o IPv4-embedded IPv6 address: is an IPv6 address which embeds a 32
bit-encoded IPv4 address [RFC6052]. An IPv4-embedded IPv6 address
can be unicast or multicast address.
o PREFIX64: is a dedicated IPv6 prefix for building IPv4-embedded
IPv6 addresses. A PREFIX64 can be of unicast or multicast.
o M_PREFIX64: denotes a multicast PREFIX64. It may belong to the
SSM range (i.e., ff3x::/32 [RFC4607]) or ASM range.
o U_PREFIX64: denotes a unicast PREFIX64 for building the IPv4-
embedded IPv6 addresses of multicast sources in SSM mode.
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3. PREFIX64 DHCPv6 Option
OPTION_PREFIX64 is defined to convey the IPv6 prefix(es) to use to
synthesize IPv4-embbedded IPv6 addresses. This option MAY enclose
one or more sub-options.
3.1. Option Format
Figure 1 shows the format of the OPTION_PREFIX64 DHCPv6 option.
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_PREFIX64 | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-option |
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| preferred-lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| valid-lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code: OPTION_PREFIX64 (TBD)
option-length: The length of enclosed sub-option(s) + 8 in octets
sub-option: One or several sub-obtions. Two sub-codes are defined
in this document:
(1) SUB_OPTION_M_PREFIX64
(2) SUB_OPTION_U_PREFIX64
preferred-lifetime: The preferred lifetime for the IPv6 prefix(es)
in the sub-option(s), expressed in units of seconds.
valid-lifetime: The valid lifetime for the IPv6 prefix(es)
in the sub-option(s), expressed in units of seconds.
Figure 1: DHCPv6 Option Format for PREFIX64
3.2. M_PREFIX64 Sub-option
This sub-option (Figure 2) is defined to convey the IPv6 multicast
prefix to use to synthesize the IPv4-embedded IPv6 addresses of the
multicast groups [I-D.boucadair-behave-64-multicast-address-format].
The conveyed multicast IPv6 prefix MAY belong to the SSM range (i.e.,
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ff3x::/32 [RFC4607]) or ASM range.
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SUB_OPTION_M_PREFIX64 | sub-option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| prefix-length | reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| M_PREFIX64 (IPv6 multicast prefix) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
sub-option-code: SUB_OPTION_M_PREFIX64 (TBD)
sub-option-len: 20 in octets
prefix-length: the length of M_PREFIX64 in bits
M_PREFIX64: the multicast prefix for constructing the IPv4-embedded
IPv6 addresses of multicast groups. It MAY belong to
SSM or ASM address range.
Figure 2: DHCPv6 Sub-option Format for M_PREFIX64
3.3. U_PREFIX64 Sub-option
This sub-option (Figure 3) is defined to convey the IPv6 unicast
prefix to be used in SSM mode for constructing the IPv4-embedded IPv6
addresses of the multicast sources. It is also used to extract the
IPv4 address from received multicast data flows (e.g.,
[I-D.ietf-softwire-dslite-multicast]). The address synthesis MUST
follow the guidelines documented at [RFC6052].
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SUB_OPTION_U_PREFIX64 | sub-option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| prefix-length | reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| U_PREFIX64 (IPv6 unicast prefix) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
sub-option-code: SUB_OPTION_U_PREFIX64 (TBD)
sub-option-len: 20 in octets
prefix-length: the length of U_PREFIX64 in bits
U_PREFIX64: the unicast prefix for constructing the IPv4-embedded
IPv6 addresses of the multicast sources in SSM mode
Figure 3: DHCPv6 Sub-option Format for U_PREFIX64
4. Client Behaviour
To retrieve the IPv6 prefixes to use to synthesize unicast and
multicast IPv4-embedded IPv6 addresses, the DHCPv6 client MUST
include OPTION_PREFIX64 in its OPTION_ORO.
If the DHCPv6 client receives more than one OPTION_PREFIX64 option
from the DHCPv6 server, only the first instance of that option MUST
be used.
When OPTION_PREFIX64 option is received from the DHCPv6 server, at
most three sub-options MAY be included.
The prefix conveyed in SUB_OPTION_U_PREFIX64 is used to synthesize
unicast IPv4-embedded IPv6 addresses as specified in [RFC6052].
The prefix conveyed in SUB_OPTION_M_PREFIX64 is used to synthesize
multicast IPv4-embedded IPv6 addresses as specified in
[I-D.boucadair-behave-64-multicast-address-format].
5. Server Behaviour
A DHCPv6 server MUST NOT reply with a value for the OPTION_PREFIX64
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if the DHCPv6 client has not explicitly included OPTION_PREFIX64 in
its OPTION_ORO.
If OPTION_PREFIX64 option is requested by the DHCPv6 client, the
DHCPv6 server MUST NOT send more than one OPTION_PREFIX64 option in
the response.
One or two SUB_OPTION_M_PREFIX64 sub-options MAY be enclosed in
OPTION_PREFIX64 DHCPv6 option. In particular, if only SSM or ASM
mode is supported, only one SUB_OPTION_M_PREFIX64 sub-option MUST be
returned to the requesting client. If both SSM and ASM mode are
supported, two SUB_OPTION_M_PREFIX64 sub-options MUST be returned.
When two SUB_OPTION_M_PREFIX64 sub-options are present, one
SUB_OPTION_M_PREFIX64 sub-option MUST convey an IPv6 prefix in SSM
range and the other one MUST enclose an IPv6 prefix in the ASM range.
If the IPv6 multicast prefix conveyed in SUB_OPTION_M_PREFIX64 is an
SSM prefix, U_PREFIX64 sub-option MUST also be present.
6. Security Considerations
The security considerations in [RFC3315] are to be considered.
7. Acknowledgements
TBD
8. IANA Considerations
A new DHCPv6 option:
OPTION_PREFIX64
and two sub-options:
SUB_OPTION_M_PREFIX64,
SUB_OPTION_U_PREFIX64
need to be assigned by IANA.
9. References
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9.1. Normative References
[I-D.boucadair-behave-64-multicast-address-format]
Boucadair, M., Qin, J., Lee, Y., Venaas, S., Li, X., and
M. Xu, "IPv4-Embedded IPv6 Multicast Address Format",
draft-boucadair-behave-64-multicast-address-format-03
(work in progress), October 2011.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for
IP", RFC 4607, August 2006.
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
October 2010.
9.2. Informative References
[I-D.ietf-softwire-dslite-multicast]
Wang, Q., Qin, J., Boucadair, M., Jacquenet, C., and Y.
Lee, "Multicast Extensions to DS-Lite Technique in
Broadband Deployments",
draft-ietf-softwire-dslite-multicast-00 (work in
progress), September 2011.
[I-D.ietf-softwire-mesh-multicast]
Xu, M., Cui, Y., Yang, S., Wu, J., Metz, C., and G.
Shepherd, "Softwire Mesh Multicast",
draft-ietf-softwire-mesh-multicast-01 (work in progress),
October 2011.
[I-D.venaas-behave-mcast46]
Venaas, S., Asaeda, H., SUZUKI, S., and T. Fujisaki, "An
IPv4 - IPv6 multicast translator",
draft-venaas-behave-mcast46-02 (work in progress),
December 2010.
[RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
Stack Lite Broadband Deployments Following IPv4
Exhaustion", RFC 6333, August 2011.
[RFC6346] Bush, R., "The Address plus Port (A+P) Approach to the
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IPv4 Address Shortage", RFC 6346, August 2011.
Authors' Addresses
Jacni Qin
ZTE
Shanghai,
China
Phone: +86 1391 8619 913
Email: jacni@jacni.com
Mohamed Boucadair
France Telecom
Rennes, 35000
France
Phone:
Email: mohamed.boucadair@orange.com
Tina Tsou
Huawei Technologies (USA)
2330 Central Expressway
Santa Clara, CA 95050
USA
Phone: +1 408 330 4424
Email: tina.tsou.zouting@huawei.com
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