draft-ietf-mboned-64-multicast-address-format-04.txt   draft-ietf-mboned-64-multicast-address-format-05.txt 
MBONED Working Group M. Boucadair, Ed. MBONED Working Group M. Boucadair, Ed.
Internet-Draft France Telecom Internet-Draft France Telecom
Updates: 3306 (if approved) J. Qin Intended status: Standards Track J. Qin
Intended status: Standards Track Cisco Expires: October 20, 2013 Cisco
Expires: February 25, 2013 Y. Lee Y. Lee
Comcast Comcast
S. Venaas S. Venaas
Cisco Systems Cisco Systems
X. Li X. Li
CERNET Center/Tsinghua CERNET Center/Tsinghua University
University
M. Xu M. Xu
Tsinghua University Tsinghua University
August 24, 2012 April 18, 2013
IPv6 Multicast Address With Embedded IPv4 Multicast Address IPv6 Multicast Address With Embedded IPv4 Multicast Address
draft-ietf-mboned-64-multicast-address-format-04 draft-ietf-mboned-64-multicast-address-format-05
Abstract Abstract
This document reserves one bit of the unicast prefix-based multicast This document reserves one bit (M-bit) of the unicast prefix-based
IPv6 address for ASM and an IPv6 multicast prefix for SSM mode to be multicast IPv6 address for ASM and an IPv6 multicast prefix for SSM
used in the context of IPv4-IPv6 interconnection. The document mode to be used in the context of IPv4-IPv6 interconnection.
specifies an algorithmic translation of an IPv6 multicast address to
a corresponding IPv4 multicast address, and vice versa. This
algorithmic translation can be used in both IPv4-IPv6 translation or
encapsulation schemes.
This document updates RFC 3306. One of the reserved bits defined in The document specifies an algorithmic translation of an IPv6
RFC 3306 has now a meaning. multicast address to a corresponding IPv4 multicast address, and vice
versa. This algorithmic translation can be used in both IPv4-IPv6
translation or encapsulation schemes.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
Status of this Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 25, 2013. This Internet-Draft will expire on October 20, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. IPv4-Embedded IPv6 Multicast Prefix & Address . . . . . . . . 5 3. IPv4-Embedded IPv6 Multicast Prefix & Address . . . . . . . . 4
3.1. Design Considerations . . . . . . . . . . . . . . . . . . 5 3.1. ASM Mode . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. ASM Mode . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.2. SSM Mode . . . . . . . . . . . . . . . . . . . . . . . . 5
3.3. SSM Mode . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.3. IPv4-Embedded IPv6 Multicast Address . . . . . . . . . . 5
3.4. IPv4-Embedded IPv6 Multicast Address . . . . . . . . . . . 7 3.4. Address Translation Algorithm . . . . . . . . . . . . . . 6
3.5. Address Translation Algorithm . . . . . . . . . . . . . . 7 3.5. Textual Representation . . . . . . . . . . . . . . . . . 6
3.6. Textual Representation . . . . . . . . . . . . . . . . . . 8 3.6. Source IPv4 Address in the IPv6 Realm . . . . . . . . . . 6
3.7. Source IPv4 Address in the IPv6 Realm . . . . . . . . . . 8 4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 8.1. Normative References . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . . 9 8.2. Informative References . . . . . . . . . . . . . . . . . 8
8.2. Informative References . . . . . . . . . . . . . . . . . . 10 Appendix A. Motivations . . . . . . . . . . . . . . . . . . . . 9
Appendix A. Motivations . . . . . . . . . . . . . . . . . . . . . 10 A.1. Why an Address Format is Needed for Multicast IPv4-IPv6
A.1. Why an Address Format is Needed for Multicast Interconnection? . . . . . . . . . . . . . . . . . . . . 9
IPv4-IPv6 Interconnection? . . . . . . . . . . . . . . . . 10 A.2. Why Identifying an IPv4-Embedded IPv6 Multicast Address
A.2. Why Identifying an IPv4-Embedded IPv6 Multicast is Required? . . . . . . . . . . . . . . . . . . . . . . 9
Address is Required? . . . . . . . . . . . . . . . . . . . 11 A.3. Location of the IPv4 Address . . . . . . . . . . . . . . 10
A.3. Location of the IPv4 Address . . . . . . . . . . . . . . . 12 Appendix B. Design Considerations . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction 1. Introduction
Various solutions (e.g., [I-D.ietf-softwire-mesh-multicast], Various solutions (e.g., [I-D.ietf-softwire-mesh-multicast],
[I-D.ietf-softwire-dslite-multicast]) have been proposed to allow [I-D.ietf-softwire-dslite-multicast]) have been proposed to allow
access to IPv4 multicast content from hosts attached to IPv6-enabled access to IPv4 multicast content from hosts attached to IPv6-enabled
domains. Even if these solutions have distinct applicability scopes domains. Even if these solutions have distinct applicability scopes
(translation vs. encapsulation) and target different use cases, they (translation vs. encapsulation) and target different use cases, they
all make use of specific IPv6 multicast addresses to embed an IPv4 all make use of specific IPv6 multicast addresses to embed an IPv4
multicast address. Particularly, the IPv4-Embedded IPv6 Multicast multicast address. Particularly, the IPv4-Embedded IPv6 Multicast
Address is used as a destination IPv6 address of multicast flows Address is used as a destination IPv6 address of multicast flows
received from an IPv4-enabled domain and injected by the IPv4-IPv6 received from an IPv4-enabled domain and injected by the IPv4-IPv6
Interconnection Function into an IPv6-enabled domain. It is also Interconnection Function into an IPv6-enabled domain. It is also
used to build an IPv6 multicast state (*, G6) or (S6, G6) used to build an IPv6 multicast state (*, G6) or (S6, G6)
corresponding to their (*, G4) or (S4, G4) IPv4 counter parts by the corresponding to their (*, G4) or (S4, G4) IPv4 counter parts by the
IPv4-IPv6 Interconnection Function. [I-D.ietf-mboned-v4v6-mcast-ps] IPv4-IPv6 Interconnection Function. [I-D.ietf-mboned-v4v6-mcast-ps]
provides more discussion about issues related to IPv4/IPv6 multicast. provides more discussion about issues related to IPv4/IPv6 multicast.
This document reserves one bit of the unicast prefix-based multicast This document reserves one bit of the unicast prefix-based multicast
IPv6 address ([RFC3306]) for Any-Source Multicast (ASM) mode and an IPv6 address ([I-D.ietf-6man-multicast-addr-arch-update]) for Any-
IPv6 multicast prefix for Source-Specific Multicast (SSM) mode to be Source Multicast (ASM) mode and an IPv6 multicast prefix for Source-
used in the context of IPv4-IPv6 interconnection. This document also Specific Multicast (SSM) mode to be used in the context of IPv4-IPv6
defines how IPv4-Embedded IPv6 Multicast Addresses are constructed. interconnection. This document also defines how IPv4-Embedded IPv6
Both IPv4-IPv6 translation and encapsulation schemes can make use of Multicast Addresses are constructed. Both IPv4-IPv6 translation and
this specification. encapsulation schemes can make use of this specification.
This specification can be used in conjunction with other extensions This specification can be used in conjunction with other extensions
such as embedding the rendezvous point [RFC3956]. Unicast prefix- such as embedding the rendezvous point [RFC3956]. Unicast prefix-
based and embedded-RP techniques are important tools to simplify IPv6 based and embedded-RP techniques are important tools to simplify IPv6
multicast deployments. Indeed, unicast prefix-based IPv6 addressing multicast deployments. Indeed, unicast prefix-based IPv6 addressing
is used in many current IPv6 multicast deployments, and has also been is used in many current IPv6 multicast deployments, and has also been
defined for IPv4, and is seen as a very useful technique. Also defined for IPv4, and is seen as a very useful technique. Also
embedded-RP is used in existing deployments. embedded-RP is used in existing deployments.
This document is a companion document to [RFC6052] which focuses This document is a companion document to [RFC6052] which focuses
skipping to change at page 4, line 50 skipping to change at page 4, line 7
2. Terminology 2. Terminology
This document makes use of the following terms: This document makes use of the following terms:
o IPv4-Embedded IPv6 Multicast Address: denotes a multicast IPv6 o IPv4-Embedded IPv6 Multicast Address: denotes a multicast IPv6
address which includes in 32 bits an IPv4 address. address which includes in 32 bits an IPv4 address.
o Multicast Prefix64 (or MPREFIX64 for short) refers to an IPv6 o Multicast Prefix64 (or MPREFIX64 for short) refers to an IPv6
multicast prefix to be used to construct IPv4-Embedded IPv6 multicast prefix to be used to construct IPv4-Embedded IPv6
Multicast Addresses. This prefix is used to build an IPv4- Multicast Addresses. This prefix is used to build an
Embedded IPv6 Multicast Address as defined in Section 3.5. IPv4-Embedded IPv6 Multicast Address as defined in Section 3.4.
Section 3.4 specifies also how to extract an IPv4 address from an
Section 3.5 specifies also how to extract an IPv4 address from an
IPv4-Embedded IPv6 Multicast Address. IPv4-Embedded IPv6 Multicast Address.
o ASM_MPREFIX64: denotes a multicast Prefix64 used in Any Source o ASM_MPREFIX64: denotes a multicast Prefix64 used in Any Source
Multicast (ASM) mode. Multicast (ASM) mode.
o SSM_MPREFIX64: denotes a multicast Prefix64 used in Source o SSM_MPREFIX64: denotes a multicast Prefix64 used in Source
Specific Multicast (SSM) mode. Specific Multicast (SSM) mode.
o IPv4-IPv6 Interconnection Function: refers to a function which is o IPv4-IPv6 Interconnection Function: refers to a function which is
enabled in a node interconnecting an IPv4-enabled domain with an enabled in a node interconnecting an IPv4-enabled domain with an
IPv6-enabled one. It can be located in various places of the IPv6-enabled one. It can be located in various places of the
multicast network. Particularly, in terms of multicast control multicast network. Particularly, in terms of multicast control
messages, it can be an IGMP/MLD Interworking Function or an IPv4- messages, it can be an IGMP/MLD Interworking Function or an
IPv6 PIM Interworking Function. An IPv4-IPv6 Interconnection IPv4-IPv6 PIM Interworking Function. An IPv4-IPv6 Interconnection
Function is configured with one or two MPREFIX64s. Function is configured with one or two MPREFIX64s.
3. IPv4-Embedded IPv6 Multicast Prefix & Address 3. IPv4-Embedded IPv6 Multicast Prefix & Address
3.1. Design Considerations 3.1. ASM Mode
The following constraints should be met when reserving dedicated
prefix(es) to be used for IPv4/IPv6 multicast interconnection:
1: Belong to ff3x::/32 and be compatible with unicast-based prefix
[RFC3306] for SSM. Note that [RFC3306] suggests to set "plen" to
0 and "network-prefix" to 0. As such, any prefix in the 33-96
range can be convenient. Given [RFC4607] indicates future
specifications may allow a non-zero network prefix field, a /33
would allow for future extensions but it has the drawback of
reserving a large block. A /96 would be adequate for the use
cases already identified in [I-D.ietf-mboned-v4v6-mcast-ps]. In
the event of any concrete extension, reserving additional
prefixes may be considered.
2: Be compatible with embedded-RP [RFC3956] and unicast-based prefix
[RFC3306] for ASM. This results in reserving a bit in the 17-20
range. Defining the 17-20 bits range to have a meaning and be
used for IPv4/IPv6 transition has the advantage of allowing for
future extensions but it may be seen as a waste of the multicast
address space. Consequently, using one of the reserved bits (in
the range 17-20) from the unicast-based IPv6 multicast address
format [RFC3306] is preferred.
Meeting (1) and (2) with the same reserved bit is not feasible
without modifying embedded-RP and unicast-based prefix
specifications; this option is avoided.
As a consequence, this document proposes to reserve a multicast
prefix for SSM and define one bit of the unicast prefix-based
multicast IPv6 address for ASM when embedding IPv4 multicast address
in an IPv6 multicast address.
3.2. ASM Mode The format specified in Figure 1 uses some bits defined in
[I-D.ietf-6man-multicast-addr-arch-update]: M-bit (20th bit position)
now has a meaning.
The format specified in Figure 1 uses some reserved bits defined in Details on design considerations are discussed in Appendix B.
[RFC3306] and [RFC3956]: the last of the 17-20 reserved bits now has
a meaning.
| 8 | 4 | 4 | 3 |1| 76 | 32 | | 8 | 4 | 4 | 3 |1| 76 | 32 |
+--------+----+----+----+-+------------------------------+----------+ +--------+----+----+----+-+------------------------------+----------+
|11111111|flgs|scop|rsvd|M| sub-group-id |v4 address| |11111111|flgs|scop|flgs|M| sub-group-id |v4 address|
+--------+----+----+----+-+-----------------------------------------+ +--------+----+----+----+-+-----------------------------------------+
"rsvd" are reserved bits.
Figure 1: IPv4-Embedded IPv6 Multicast Address Format: ASM Mode Figure 1: IPv4-Embedded IPv6 Multicast Address Format: ASM Mode
The description of the fields is as follows: The description of the fields is as follows:
o "flgs" and "scop" fields are defined in [RFC3956].
o "rsvd": These 3 bits are reserved. The usage of these bits is the o "flgs" fields are defined in
same as defined in [RFC3306]. [I-D.ietf-6man-multicast-addr-arch-update].
o "scop" field is defined in [RFC3956].
o M (20th bit position): When this bit is set to 1, it indicates o M (20th bit position): When this bit is set to 1, it indicates
that a multicast IPv4 address is embedded in the low-order 32 bits that a multicast IPv4 address is embedded in the low-order 32 bits
of the multicast IPv6 address. of the multicast IPv6 address.
o sub-group-id: This field is configurable according to local o sub-group-id: This field is configurable according to local
policies (e.g., enable embedded-RP) of the entity managing the policies (e.g., enable embedded-RP) of the entity managing the
IPv4-IPv6 Interconnection Function. This field MUST follow the IPv4-IPv6 Interconnection Function. This field MUST follow the
recommendations specified in [RFC3306] if unicast-based prefix is recommendations specified in [RFC3306] if unicast-based prefix is
used or the recommendations specified in [RFC3956] if embedded-RP used or the recommendations specified in [RFC3956] if embedded-RP
is used. The default value is all zeros. is used. The default value is all zeros.
o The low-order 32 bits MUST include an IPv4 multicast address when o The low-order 32 bits MUST include an IPv4 multicast address when
the M-bit is set to 1. The enclosed IPv4 multicast address SHOULD the M-bit is set to 1. The enclosed IPv4 multicast address SHOULD
NOT be in 232/8 range. NOT be in 232/8 range.
skipping to change at page 6, line 42 skipping to change at page 5, line 15
o sub-group-id: This field is configurable according to local o sub-group-id: This field is configurable according to local
policies (e.g., enable embedded-RP) of the entity managing the policies (e.g., enable embedded-RP) of the entity managing the
IPv4-IPv6 Interconnection Function. This field MUST follow the IPv4-IPv6 Interconnection Function. This field MUST follow the
recommendations specified in [RFC3306] if unicast-based prefix is recommendations specified in [RFC3306] if unicast-based prefix is
used or the recommendations specified in [RFC3956] if embedded-RP used or the recommendations specified in [RFC3956] if embedded-RP
is used. The default value is all zeros. is used. The default value is all zeros.
o The low-order 32 bits MUST include an IPv4 multicast address when o The low-order 32 bits MUST include an IPv4 multicast address when
the M-bit is set to 1. The enclosed IPv4 multicast address SHOULD the M-bit is set to 1. The enclosed IPv4 multicast address SHOULD
NOT be in 232/8 range. NOT be in 232/8 range.
3.3. SSM Mode 3.2. SSM Mode
For SSM mode, and given what is discussed in Section 3.1, the For SSM mode, and given what is discussed in Appendix B, the
following IPv6 prefix to embed IPv4 multicast addresses is reserved: following IPv6 prefix to embed IPv4 multicast addresses is reserved:
o ff3x:0:8000::/96 ('x' is any valid scope). o ff3x:0:8000::/96 ('x' is any valid scope).
3.4. IPv4-Embedded IPv6 Multicast Address 3.3. IPv4-Embedded IPv6 Multicast Address
For the delivery of the IPv4-IPv6 multicast interconnection services, For the delivery of the IPv4-IPv6 multicast interconnection services,
a dedicated multicast prefix denoted as MPREFIX64 should be a dedicated multicast prefix denoted as MPREFIX64 should be
provisioned (e.g., using NETCONF or provisioned (e.g., using NETCONF or
[I-D.ietf-softwire-multicast-prefix-option]) to any function [I-D.ietf-softwire-multicast-prefix-option]) to any function
requiring to build an IPv4-Embedded IPv6 Multicast Address based on requiring to build an IPv4-Embedded IPv6 Multicast Address based on
an IPv4 multicast address. MPREFIX64 can be of ASM or SSM type. an IPv4 multicast address. MPREFIX64 can be of ASM or SSM type.
When both modes are used, two prefixes are required to be When both modes are used, two prefixes are required to be
provisioned. provisioned.
skipping to change at page 7, line 43 skipping to change at page 6, line 12
When several MPREFIX64 are available, it is RECOMMENDED to use the When several MPREFIX64 are available, it is RECOMMENDED to use the
MPREFIX64 which preserve the scope of the IPv4 multicast address. MPREFIX64 which preserve the scope of the IPv4 multicast address.
| 96 | 32 | | 96 | 32 |
+------------------------------------------------------+----------+ +------------------------------------------------------+----------+
| MPREFIX64 |v4 address| | MPREFIX64 |v4 address|
+------------------------------------------------------+----------+ +------------------------------------------------------+----------+
Figure 2: IPv4-Embedded IPv6 Multicast Address Format Figure 2: IPv4-Embedded IPv6 Multicast Address Format
3.5. Address Translation Algorithm 3.4. Address Translation Algorithm
IPv4-Embedded IPv6 Multicast Addresses are composed according to the IPv4-Embedded IPv6 Multicast Addresses are composed according to the
following algorithm: following algorithm:
o Concatenate the MPREFIX64 and the 32 bits of the IPv4 address to o Concatenate the MPREFIX64 and the 32 bits of the IPv4 address to
obtain a 128-bit address. obtain a 128-bit address.
The IPv4 multicast addresses are extracted from the IPv4-Embedded The IPv4 multicast addresses are extracted from the IPv4-Embedded
IPv6 Multicast Addresses according to the following algorithm: IPv6 Multicast Addresses according to the following algorithm:
o If the multicast address has the 20th bit set to 1 or it matches o If the multicast address has the 20th bit set to 1 or it matches
ff3x:0:8000::/96 or a preconfigured MPREFIX64, extract the last 32 ff3x:0:8000::/96 or a preconfigured MPREFIX64, extract the last 32
bits of the IPv6 multicast address. bits of the IPv6 multicast address.
3.6. Textual Representation 3.5. Textual Representation
The embedded IPv4 address in an IPv6 multicast address is included in The embedded IPv4 address in an IPv6 multicast address is included in
the last 32 bits; therefore dotted decimal notation can be used. the last 32 bits; therefore dotted decimal notation can be used.
3.7. Source IPv4 Address in the IPv6 Realm 3.6. Source IPv4 Address in the IPv6 Realm
An IPv4 source is represented in the IPv6 realm with its IPv4- An IPv4 source is represented in the IPv6 realm with its
converted IPv6 address [RFC6052]. IPv4-converted IPv6 address [RFC6052].
4. Examples 4. Examples
Figure 3 provides some examples of ASM IPv4-Embedded IPv6 Address Figure 3 provides some examples of ASM IPv4-Embedded IPv6 Address
while Figure 4 provides an example of SSM IPv4-Embedded IPv6 Address. while Figure 4 provides an example of SSM IPv4-Embedded IPv6 Address.
IPv4 multicast addresses used in the examples are derived from the IPv4 multicast addresses used in the examples are derived from the
IPv4 multicast block reserved for documentation in [RFC6676]. IPv4 multicast block reserved for documentation in [RFC6676].
+----------------------+--------------+-----------------------------+ +----------------------+--------------+-----------------------------+
skipping to change at page 8, line 35 skipping to change at page 7, line 4
IPv4 multicast addresses used in the examples are derived from the IPv4 multicast addresses used in the examples are derived from the
IPv4 multicast block reserved for documentation in [RFC6676]. IPv4 multicast block reserved for documentation in [RFC6676].
+----------------------+--------------+-----------------------------+ +----------------------+--------------+-----------------------------+
| MPREFIX64 | IPv4 address | IPv4-Embedded IPv6 Address | | MPREFIX64 | IPv4 address | IPv4-Embedded IPv6 Address |
+----------------------+--------------+-----------------------------+ +----------------------+--------------+-----------------------------+
| ff3x:z000:0:abc::/96 | 233.252.0.1 |ff3x:z000:0:abc::233.252.0.1 | | ff3x:z000:0:abc::/96 | 233.252.0.1 |ff3x:z000:0:abc::233.252.0.1 |
| ff7x:z000:0:abc::/96 | 233.252.0.2 |ff7x:z000:0:abc::233.252.0.2 | | ff7x:z000:0:abc::/96 | 233.252.0.2 |ff7x:z000:0:abc::233.252.0.2 |
+----------------------+--------------+-----------------------------+ +----------------------+--------------+-----------------------------+
where: where:
"x" is any valid scope "x" is any valid scope
"z" is any 4 bits where the last bit is set (e.g., 1, 3, 7, ...) "z" is any 4 bits where the last bit is set (e.g., 1, 3, 7, ...)
Figure 3: Example of ASM IPv4-embedded IPv6 address Figure 3: Example of ASM IPv4-embedded IPv6 address
+---------------------+--------------+----------------------------+ +---------------------+--------------+----------------------------+
| MPREFIX64 | IPv4 address | IPv4-Embedded IPv6 Address | | MPREFIX64 | IPv4 address | IPv4-Embedded IPv6 Address |
+---------------------+--------------+----------------------------+ +---------------------+--------------+----------------------------+
| ff3x:0:8000::/96 | 233.252.0.5 | ff3x:0:8000::233.252.0.5 | | ff3x:0:8000::/96 | 233.252.0.5 | ff3x:0:8000::233.252.0.5 |
+---------------------+--------------+----------------------------+ +---------------------+--------------+----------------------------+
Figure 4: Example of SSM IPv4-embedded IPv6 address Figure 4: Example of SSM IPv4-embedded IPv6 address
5. IANA Considerations 5. IANA Considerations
This document requests IANA to reserve: This document requests IANA to reserve:
o ff3x:0:8000::/96 SSM range to embed an IPv4 multicast address in o ff3x:0:8000::/96 SSM range to embed an IPv4 multicast address in
the last 32 bits. the last 32 bits.
6. Security Considerations 6. Security Considerations
This document defines an algorithmic translation of an IPv6 multicast This document defines an algorithmic translation of an IPv6 multicast
address into an IPv4 multicast address, and vice versa. The security address into an IPv4 multicast address, and vice versa. The security
considerations discussed in [RFC6052] are to be taken into considerations discussed in [RFC6052] are to be taken into
consideration. consideration.
7. Acknowledgements 7. Acknowledgements
Many thanks to R. Bonica, B. Sarikaya, P. Savola, T. Tsou, C. Many thanks to R. Bonica, B. Sarikaya, P. Savola, T. Tsou, C.
Bormann, T. Chown and P. Koch for their comments and review. Bormann, T. Chown, P. Koch, B. Haberman, and B. Hinden for their
comments and review.
8. References 8. References
8.1. Normative References 8.1. Normative References
[I-D.ietf-6man-multicast-addr-arch-update]
Boucadair, M. and S. Venaas, "Updates to the IPv6
Multicast Addressing Architecture", draft-ietf-6man-
multicast-addr-arch-update-00 (work in progress), April
2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3306] Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6 [RFC3306] Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6
Multicast Addresses", RFC 3306, August 2002. Multicast Addresses", RFC 3306, August 2002.
[RFC3307] Haberman, B., "Allocation Guidelines for IPv6 Multicast [RFC3307] Haberman, B., "Allocation Guidelines for IPv6 Multicast
Addresses", RFC 3307, August 2002. Addresses", RFC 3307, August 2002.
[RFC3956] Savola, P. and B. Haberman, "Embedding the Rendezvous [RFC3956] Savola, P. and B. Haberman, "Embedding the Rendezvous
Point (RP) Address in an IPv6 Multicast Address", Point (RP) Address in an IPv6 Multicast Address", RFC
RFC 3956, November 2004. 3956, November 2004.
[RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for [RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for
IP", RFC 4607, August 2006. IP", RFC 4607, August 2006.
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X. [RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052, Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
October 2010. October 2010.
8.2. Informative References 8.2. Informative References
[I-D.ietf-behave-nat64-learn-analysis] [I-D.ietf-behave-nat64-learn-analysis]
Korhonen, J. and T. Savolainen, "Analysis of solution Korhonen, J. and T. Savolainen, "Analysis of solution
proposals for hosts to learn NAT64 prefix", proposals for hosts to learn NAT64 prefix", draft-ietf-
draft-ietf-behave-nat64-learn-analysis-03 (work in behave-nat64-learn-analysis-03 (work in progress), March
progress), March 2012. 2012.
[I-D.ietf-mboned-v4v6-mcast-ps] [I-D.ietf-mboned-v4v6-mcast-ps]
Jacquenet, C., Boucadair, M., Lee, Y., Qin, J., Tsou, T., Jacquenet, C., Boucadair, M., Lee, Y., Qin, J., Tsou, T.,
and Q. Sun, "IPv4-IPv6 Multicast: Problem Statement and and Q. Sun, "IPv4-IPv6 Multicast: Problem Statement and
Use Cases", draft-ietf-mboned-v4v6-mcast-ps-00 (work in Use Cases", draft-ietf-mboned-v4v6-mcast-ps-02 (work in
progress), May 2012. progress), March 2013.
[I-D.ietf-softwire-dslite-multicast] [I-D.ietf-softwire-dslite-multicast]
Qin, J., Boucadair, M., Jacquenet, C., Lee, Y., and Q. Qin, J., Boucadair, M., Jacquenet, C., Lee, Y., and Q.
Wang, "Delivery of IPv4 Multicast Services to IPv4 Clients Wang, "Delivery of IPv4 Multicast Services to IPv4 Clients
over an IPv6 Multicast Network", over an IPv6 Multicast Network", draft-ietf-softwire-
draft-ietf-softwire-dslite-multicast-03 (work in dslite-multicast-05 (work in progress), April 2013.
progress), August 2012.
[I-D.ietf-softwire-mesh-multicast] [I-D.ietf-softwire-mesh-multicast]
Xu, M., Cui, Y., Wu, J., Yang, S., Metz, C., and G. Xu, M., Cui, Y., Wu, J., Yang, S., Metz, C., and G.
Shepherd, "Softwire Mesh Multicast", Shepherd, "Softwire Mesh Multicast", draft-ietf-softwire-
draft-ietf-softwire-mesh-multicast-03 (work in progress), mesh-multicast-04 (work in progress), January 2013.
July 2012.
[I-D.ietf-softwire-multicast-prefix-option] [I-D.ietf-softwire-multicast-prefix-option]
Boucadair, M., Qin, J., Tsou, T., and X. Deng, "DHCPv6 Boucadair, M., Qin, J., Tsou, T., and X. Deng, "DHCPv6
Option for IPv4-Embedded Multicast and Unicast IPv6 Option for IPv4-Embedded Multicast and Unicast IPv6
Prefixes", draft-ietf-softwire-multicast-prefix-option-01 Prefixes", draft-ietf-softwire-multicast-prefix-option-04
(work in progress), August 2012. (work in progress), April 2013.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, July 2006. Description Protocol", RFC 4566, July 2006.
[RFC6676] Venaas, S., Parekh, R., Van de Velde, G., Chown, T., and [RFC6676] Venaas, S., Parekh, R., Van de Velde, G., Chown, T., and
M. Eubanks, "Multicast Addresses for Documentation", M. Eubanks, "Multicast Addresses for Documentation", RFC
RFC 6676, August 2012. 6676, August 2012.
Appendix A. Motivations Appendix A. Motivations
A.1. Why an Address Format is Needed for Multicast IPv4-IPv6 A.1. Why an Address Format is Needed for Multicast IPv4-IPv6
Interconnection? Interconnection?
Arguments why an IPv6 address format is needed to embed multicast Arguments why an IPv6 address format is needed to embed multicast
IPv4 address are quite similar to those of [RFC6052]. Concretely, IPv4 address are quite similar to those of [RFC6052]. Concretely,
the definition of a multicast address format embedding a multicast the definition of a multicast address format embedding a multicast
IPv4 address allows: IPv4 address allows:
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o Minimal operational constraints on the multicast address o Minimal operational constraints on the multicast address
management: IPv6 multicast addresses can be constructed using what management: IPv6 multicast addresses can be constructed using what
has been deployed for IPv4 delivery mode. has been deployed for IPv4 delivery mode.
A.2. Why Identifying an IPv4-Embedded IPv6 Multicast Address is A.2. Why Identifying an IPv4-Embedded IPv6 Multicast Address is
Required? Required?
Reserving a dedicated multicast prefix for IPv4-IPv6 interconnection Reserving a dedicated multicast prefix for IPv4-IPv6 interconnection
purposes is a means to guide the address selection process at the purposes is a means to guide the address selection process at the
receiver side; in particular it assists the receiver to select the receiver side; in particular it assists the receiver to select the
appropriate IP multicast address while avoiding to involve an IPv4- appropriate IP multicast address while avoiding to involve an
IPv6 interconnection function in the path. IPv4-IPv6 interconnection function in the path.
Two use cases to illustrate this behavior are provided below: Two use cases to illustrate this behavior are provided below:
1. An ALG is required to help an IPv6 receiver to select the 1. An ALG is required to help an IPv6 receiver to select the
appropriate IP address when only the IPv4 address is advertised appropriate IP address when only the IPv4 address is advertised
(e.g., using SDP); otherwise the access to the IPv4 multicast (e.g., using SDP); otherwise the access to the IPv4 multicast
content can not be offered to the IPv6 receiver. The ALG may be content can not be offered to the IPv6 receiver. The ALG may be
located downstream the receiver. As such, the ALG does not know located downstream the receiver. As such, the ALG does not know
in advance whether the receiver is dual-stack or IPv6-only. The in advance whether the receiver is dual-stack or IPv6-only. The
ALG may be tuned to insert both the original IPv4 address and ALG may be tuned to insert both the original IPv4 address and
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A.3. Location of the IPv4 Address A.3. Location of the IPv4 Address
There is no strong argument to allow for flexible options to encode There is no strong argument to allow for flexible options to encode
the IPv4 address inside the multicast IPv6 address. The option the IPv4 address inside the multicast IPv6 address. The option
retained by the authors is to encode the multicast IPv4 address in retained by the authors is to encode the multicast IPv4 address in
the low-order 32 bits of the IPv6 address. the low-order 32 bits of the IPv6 address.
This choice is also motivated by the need to be compliant with This choice is also motivated by the need to be compliant with
[RFC3306] and [RFC3956]. [RFC3306] and [RFC3956].
Appendix B. Design Considerations
The following constraints should be met when reserving dedicated
prefix(es) to be used for IPv4/IPv6 multicast interconnection:
1: Belong to SSM prefix range (preferably ff3x::/32) and be
compatible with unicast-based prefix [RFC3306] for SSM. Note that
[RFC3306] suggests to set "plen" to 0 and "network-prefix" to 0.
As such, any prefix in the 33-96 range can be convenient. Given
[RFC4607] indicates future specifications may allow a non-zero
network prefix field, a /33 would allow for future extensions but
it has the drawback of reserving a large block. A /96 would be
adequate for the use cases already identified in
[I-D.ietf-mboned-v4v6-mcast-ps]. In the event of any concrete
extension, reserving additional prefixes may be considered.
2: Be compatible with embedded-RP [RFC3956] and unicast-based prefix
[RFC3306] for ASM. This results in associating a meaning with one
of the reserved bits in
[I-D.ietf-6man-multicast-addr-arch-update]. Defining the 17-20
bits range to have a meaning and be used for IPv4/IPv6 transition
has the advantage of allowing for future extensions but it may be
seen as a waste of the multicast address space. Consequently,
using one of the reserved bits (in the range 17-20) from the
unicast-based IPv6 multicast address format [RFC3306] is
preferred.
Meeting (1) and (2) with the same reserved bit is not feasible
without modifying embedded-RP and unicast-based prefix
specifications; this option is avoided.
As a consequence, this document proposes to reserve a multicast
prefix for SSM and define one bit of the unicast prefix-based
multicast IPv6 address for ASM when embedding IPv4 multicast address
in an IPv6 multicast address.
Authors' Addresses Authors' Addresses
Mohamed Boucadair (editor) Mohamed Boucadair (editor)
France Telecom France Telecom
Rennes, 35000 Rennes 35000
France France
Email: mohamed.boucadair@orange.com Email: mohamed.boucadair@orange.com
Jacni Qin Jacni Qin
Cisco Cisco
China China
Email: jacni@jacni.com Email: jacni@jacni.com
skipping to change at page 13, line 15 skipping to change at page 12, line 15
Cisco Systems Cisco Systems
Tasman Drive Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
USA USA
Email: stig@cisco.com Email: stig@cisco.com
Xing Li Xing Li
CERNET Center/Tsinghua University CERNET Center/Tsinghua University
Room 225, Main Building, Tsinghua University Room 225, Main Building, Tsinghua University
Beijing, 100084 Beijing 100084
P.R. China P.R. China
Phone: +86 10-62785983 Phone: +86 10-62785983
Email: xing@cernet.edu.cn Email: xing@cernet.edu.cn
Mingwei Xu Mingwei Xu
Tsinghua University Tsinghua University
Department of Computer Science, Tsinghua University Department of Computer Science, Tsinghua University
Beijing, 100084 Beijing 100084
P.R.China P.R.China
Phone: +86-10-6278-5822 Phone: +86-10-6278-5822
Email: xmw@cernet.edu.cn Email: xmw@cernet.edu.cn
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