Network Working Group M. Boucadair Internet-Draft France Telecom Updates: 4192 (if approved) J. Qin Intended status: Standards Track ZTE Expires: July 4, 2011 Y. Lee Comcast December 31, 2010 IPv4-Embedded IPv6 Multicast Address Format draft-boucadair-behave-64-multicast-address-format-00 Abstract This document specifies an extension to the IPv6 multicast addressing architecture to be used in the context of IPv4-IPv6 interconnection. In particular, this document defines an address format for IPv4- embedded IPv6 multicast addresses. This address format can be used for IPv4-IPv6 translation or encapsulation schemes. 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]. 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 http://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 July 4, 2011. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. Boucadair, et al. Expires July 4, 2011 [Page 1]
Internet-Draft 64 Multicast Address Format December 2010 This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Motivations . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. IPv4-Embedded IPv6 Multicast Address Format . . . . . . . . . . 4 4.1. Role of the S-bit . . . . . . . . . . . . . . . . . . . . . 6 4.2. Textual Representation . . . . . . . . . . . . . . . . . . 6 4.3. Lifetime of the IPv4-Embeded IPv6 Multicast Address . . . . 6 4.4. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.5. SSM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5. Multicast PREFIX64 . . . . . . . . . . . . . . . . . . . . . . 6 6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 8. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 10.1. Normative References . . . . . . . . . . . . . . . . . . . 8 10.2. Informative References . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Boucadair, et al. Expires July 4, 2011 [Page 2]
Internet-Draft 64 Multicast Address Format December 2010 1. Introduction This document specifies an extension to the multicast IPv6 addressing architecture [RFC4291]. This extension is used for building IPv4- embedded IPv6 multicast addresses. This specification can be used in conjunction with other extensions such as building unicast prefix-based multicast IPv6 address [RFC3306] or embedding the rendez-vous point [RFC3956]. This is left to the taste of operators. In particular, the extension defined in this document can be used in a context where [RFC3306] and [RFC3956] are not implemented. This document updates [RFC6052] which focuses exclusively on IPv4- embeded IPv6 unicast addresses. 1.1. Scope The address format defined in this document applies for both IPv4- IPv6 translation and encapsulation schemes. It is out of scope of this document to define the overall procedure for the delivery of IPv4-embeded IPv6 multicast to the requesting receivers. Practical details about the procedure is defined in specific documents such as [I-D.venaas-behave-v4v6mc-framework] and [I-D.qin-softwire-dslite-multicast]. 2. Terminology This document makes use of the following terms: o IPv4-embeded IPv6 multicast address: denotes a multicast IPv6 address which includes in 32 bits an IPv4 address. The format to build such address is defined in Section 4. o IPv4-IPv6 Interconnection Function: refers to a function which is enabled in a node interconnecting an IPv4-enabled domain with an IPv6-enabled one. An IPv4-IPv6 Interconnection Function can be implemented using encapsulation or translation techniques. t can be located in various places of the multicast network, and that is the deployment specific issue left to operators. Particularly, in terms of multicast control message, it can be an "IGMP/MLD interworking function" or an "IPv4-IPv6 PIM interworking function". Since from the protocol perspective, the MLD protocol is a translation of IGMP in the semantics of IPv6 and PIM has been designed to accommodate both IPv4 and IPv6, no extra functionality is needed to be defined but to follow the address format specified Boucadair, et al. Expires July 4, 2011 [Page 3]
Internet-Draft 64 Multicast Address Format December 2010 in Section 4. In terms of multicast traffic forwarding, it can be translation-based or encapsulation- based. o Multicast Prefix64 (or MPREFIX64 for short) refers to an IPv6 multicast prefix to be used to construct IPv4-embedded IPv6 multicast addresses. o ASM_MPREFIX64: denotes an MPREFIX64 used in ASM mode. o SSM_MPREFIX64: denotes an MPREFIX64 used in SSM mode. 3. Motivations Recently various solutions (e.g., [I-D.venaas-behave-v4v6mc-framework], [I-D.xu-softwire-mesh-multicast] or [I-D.qin-softwire-dslite-multicast]) have been proposed to allow access to IPv4 multicast content from hosts attached to IPv6-enabled domains. Even if these solutions have distinct applicability scopes (translation vs. encapsulation) and target various use cases, they all make use of specific IPv6 multicast addresses to embed an IPv4 multicast address. Particularly, the IPv4-embeded IPv6 multicast address is used as a destination IPv6 address of multicast flows received from the IPv4-enabled domain and injected by the IPv4-IPv6 Interconnection Function into the IPv6-enabled domain. It is also used to build the IPv6 multicast state (*, G6) or (S6,G6) corresponding to their (*, G4) or (S4,G4) IPv4 counter parts by the IPv4-IPv6 Interconnection Function. This document aims at harmonizing the definition of an IPv4-embeded IPv6 address format. 4. IPv4-Embedded IPv6 Multicast Address Format This document specifies a modification to the IPv6 multicast address format [RFC4291] by defining the first higher bit of the "flags" field. Boucadair, et al. Expires July 4, 2011 [Page 4]
Internet-Draft 64 Multicast Address Format December 2010 | 8 | 4 | 4 | 4 | 76 | 32 | +--------+----+----+----+------------------------------+----------+ |11111111|flgs|scop|sche| sub-group-id |v4 address| +--------+----+----+----+-----------------------------------------+ +-+-+-+-+ flgs is a set of four flags: |M|R|P|T| +-+-+-+-+ +-+-+-+-+ IPv4-IPv6 interconnection scheme bits: |r|r|r|S| +-+-+-+-+ Figure 1: IPv4-Embedded IPv6 Multicast Address Format The description of the fields is as follows: o Binary 11111111 at the start of the address identifies the address as being a multicast address. o Flags * "T-bit" is defined in [RFC4291]. * "P-bit" is defined in [RFC3306]. * "R-bit" is defined in [RFC3956]. * "M-bit" when set to 1 indicates that an IPv4 address is embedded in the last 32 bits of the multicast IPv6 address o Scope is defined in [RFC4291]. Allowed values are 8 for Organization-Local scope or E for Global scope. o Reserved bits: the 5th higher bit "S-bit" indicates the scheme used to carry IPv6 multicast flows in the IPv6 domain. When set to 0, it indicates flows are transported using IPv4-in-IPv6 encapsulation scheme (i.e., IPv4-IPv6 Interconnection Function is an IPv4-IPv6 encapsulator). When set to 1, it indicates the multicast flows are to be transported in native IPv6 (i.e., IPv4- IPv6 Interconnection Function is an IPv4-IPv6 translator). All remaining bits SHOULD be set to 0 by default. This bit is only used by the IPv4-IPv6 Interconnection Function. See Section 4.1. o sub-group-id: This field is configurable according to local policies of the entity managing the IPv4-IPv6 Interconnection Function. The default value is all zeros. [[NOTE: 64??]] Boucadair, et al. Expires July 4, 2011 [Page 5]
Internet-Draft 64 Multicast Address Format December 2010 o The last 32 bits MUST include an IPv4 multicast address. [[Discussion note: Below is provided an alternative proposal for the location of the bits]] +-+-+-+-+ flgs is a set of four flags: |0|R|P|T| +-+-+-+-+ +-+-+-+-+ IPv4-IPv6 interconnection scheme bits: |r|r|M|S| +-+-+-+-+ 4.1. Role of the S-bit IPv4-IPv6 encapsulator and translator may be embedded in the same device or even implemented with the same software module. In order to help the function whether an encapsulated IPv6 multicast packets or translated IPv6 ones are to be transferred; the "S-bit" is used for that purpose. 4.2. Textual Representation The embedded IPv4 address is included in the last 32 bits; therefore dotted decimal notation can be used. 4.3. Lifetime of the IPv4-Embeded IPv6 Multicast Address TBC. 4.4. Scope Fixed or let it be configurable. 4.5. SSM Further elaboration on SSM [RFC4607]. 5. Multicast PREFIX64 For the delivery of the IPv4-IPv6 multicast interconnection services, a dedicated multicast prefix denoted as MPREFIX64 should be provisioned to any function requiring to build an IPv4-embedded IPv6 multicast address based on an IPv4 multicast address. MPREFIX64 can be of ASM or SSM type. The structure of the MPREFIX64 follows the guidelines specified in Boucadair, et al. Expires July 4, 2011 [Page 6]
Internet-Draft 64 Multicast Address Format December 2010 Section 4. MPREFIX64 MAY be of any length from /32 to /96; /96 being the RECOMMENDED prefix length as shown in Figure 3). The format of the MPREFIX64 should be compatible with what proposed in [RFC3306] and [RFC3956] if corresponding mechanisms are used. | 8 | 4 | 4 | 4 | 76 | 32 | +--------+----+----+----+-----------------------------+----------+ |11111111|flgs|scop|sche| sub-group-id |v4 address| +--------+----+----+----+-----------------------------+----------+ | | | v v | +-----------------------------------------------------+----------+ | MPREFIX64 |v4 address| +-----------------------------------------------------+----------+ Figure 3: MPREFIX64 6. Examples To be added: encapsulation or and translation. 7. IANA Considerations TBC. 8. Security Considerations This document defined an address format to embed an IPv4 multicast address in an IPv6 multicast address. The same security considerations as those discussed in [RFC6052] are to be taken into consideration. 9. Acknowledgements TBC. 10. References Boucadair, et al. Expires July 4, 2011 [Page 7]
Internet-Draft 64 Multicast Address Format December 2010 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3306] Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6 Multicast Addresses", RFC 3306, August 2002. [RFC3956] Savola, P. and B. Haberman, "Embedding the Rendezvous Point (RP) Address in an IPv6 Multicast Address", RFC 3956, November 2004. [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, February 2006. [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. 10.2. Informative References [I-D.qin-softwire-dslite-multicast] Wang, Q., Qin, J., Sun, P., Boucadair, M., and C. Jacquenet, "Multicast Extensions to DS-Lite in Broadband Deployments", draft-qin-softwire-dslite-multicast-01 (work in progress), October 2010. [I-D.venaas-behave-v4v6mc-framework] Venaas, S., Li, X., and C. Bao, "Framework for IPv4/IPv6 Multicast Translation", draft-venaas-behave-v4v6mc-framework-02 (work in progress), December 2010. [I-D.xu-softwire-mesh-multicast] Xu, M., Cui, Y., Yang, S., Metz, C., and G. Shepherd, "Softwire Mesh Multicast", draft-xu-softwire-mesh-multicast-00 (work in progress), October 2010. Boucadair, et al. Expires July 4, 2011 [Page 8]
Internet-Draft 64 Multicast Address Format December 2010 Authors' Addresses Mohamed Boucadair France Telecom Rennes, 35000 France Email: mohamed.boucadair@orange-ftgroup.com Jacni Qin ZTE Shanghai China Email: jacniq@gmail.com Yiu L. Lee Comcast Email: yiu_lee@cable.comcast.com URI: http://www.comcast.com Boucadair, et al. Expires July 4, 2011 [Page 9]