Network Working Group                                   N. Kumar
Internet Draft                                         S. Venaas
Intended status: Standard                     Cisco Systems, Inc
Expires: February 2013                            August 3, 2012



            Well-Known Prefix for V4V6 Mcast Translation
           draft-kumar-mboned-64mcast-wkp-address-00.txt


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   Provisions and are provided without warranty as described in
   the Simplified BSD License.

Abstract

   This document reserves 2 Well known IPv6 Multicast prefixes
   for the usage of IPv4-IPv6 Multicast transition.  These
   prefixes will be used to embed IPv4 group address as and when
   required.

Table of Contents


   1. Introduction...................................................2
   2. Terminology....................................................3
   3. Well-Known Prefix..............................................3
      3.1. SSM64PREFIX Format........................................3
      3.2. ASM64PREFIX Format........................................4
      3.3. Text Representation.......................................5
   4. Well-Known Prefix Usage........................................5
   5. Use Cases......................................................5
      5.1. IPv4 Receiver and Source connected over IPv6-Only
      network........................................................6
   6. Security Considerations........................................6
   7. IANA Considerations............................................7
   8. References.....................................................7
      8.1. Normative References......................................7
      8.2. Informative References....................................7
   9. Acknowledgments................................................8



1. Introduction

   As part of IPv4 to IPv6 migration, there are multiple
   standards developed for smooth transition for Unicast.
   Section 3 of [I-D.ietf-mboned-v4v6-mcast-ps] specifies
   different possible scenarios for IPv4 to IPv6 multicast
   transition as below,

      1. IPv4 Receiver and Source connected over IPv6-Only
        network
      2. IPv6 Receiver Connected to IPv4 Source through IPv4
        multicast access network and IPv6 Multicast network.
      3. IPv6 Receiver and Source connected to IPv4-Only network.
      4. IPv6 Receiver and IPv4 Source.
      5. IPv4 Receiver and IPv6 Source.


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   Section 3.6 of [I-D.ietf-mboned-v4v6-mcast-ps] identifies the
   use cases involving IPv4 source as highest priority.

   There are also various solutions proposed (ex., [I-D.ietf-
   softwire-mesh-multicast], [I-D.ietf-softwire-dslite-
   multicast]) addressing the above use cases requirement which
   requires to embed IPv4 multicast address into IPv6 address.
   This IPv4-embedded IPv6 multicast address will be used as
   group address within IPv6 cloud.

   There were multiple options considered and discussed and this
   draft is to document Well-known prefix option.

   This document reserves 2 Well-Known prefixes from IPv6
   Multicast address range which will be used for IPv4-IPv6
   transition.



2. Terminology



   (S4, G4)/(*, G4): (S, G) or (*, G) in IPv4 address format

   (S6, G6)/(*, G6): (S, G) or (*, G) in IPv6 address format

   SSM64PREFIX: Well-Known prefix reserved for SSM range IPv6
   Multicast address as specified in Section 3.1.

   ASM64PREFIX: Well-Known prefix reserved for ASM range IPv6
   Multicast address as specified in Section 3.2.



3. Well-Known Prefix

   This document reserves the below two address prefixes from
   IPv6 Multicast address range for IPv4-IPv6 transition.



3.1. SSM64PREFIX Format

   SSM64PREFIX is the prefix reserved from IPv6 SSM range
   represented as below,



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   |   8    |  4 |  4 |   8    |    8   | 16 |    48   |    32    |
   +--------+----+----+--------+--------+---------~----+----------+
   |11111111|0011|scop|00000000|00000000| WKP|0000~0000| V4-group |
   +--------+----+----+--------+--------+----+----~----+----------+


   Scop : Scope as specified in [RFC4291]

   WKP : Set to 04E6 in hexadecimal format.

   V4-group : IPv4 multicast group address



   The textual representation of SSM64PREFIX will be as below,

   FF3x:0:0:04E6::/96



3.2. ASM64PREFIX Format

   ASM64PREFIX is the prefix reserved from IPv6 ASM range
   represented as below,



   |   8    |  4 |  4 |   8    |    8   | 16 |    48   |    32    |
   +--------+----+----+--------+--------+---------~----+----------+
   |11111111|0000|scop|00000000|00000000| WKP|0000~0000| V4-group |
   +--------+----+----+--------+--------+----+----~----+----------+


   Scop : Scope as specified in [RFC4291]

   WKP : Set to 04E6 in hexadecimal format.

   V4-group : IPv4 multicast group address



   The textual representation of ASM64PREFIX will be as below,

   FF0x:0:0:04E6::/96



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3.3. Text Representation



   IPv4-embedded IPv6 Multicast address can be represented in
   text with IPv4 group address in dotted decimal notation or
   hexadecimal notation in conformity with Section 2.2 of
   [RFC4291].

   Below are the example of text representation for ASM64PREFIX
   and SSM64PREFIX,



    +-------------------+--------------+------------------------------+
    | Well-Known Prefix | IPv4 address |V4-Embedded V6 group address  |
    +-------------------+--------------+------------------------------+
    | FF0x:0:0:4E6::/96 |  233.252.0.1 |  FF0X:0:0:04E6::233.252.0.1  |
    |                   |              |           (OR)               |
    |                   |              |   FF0X:0:0:04E6::E9FC:0001   |
    +-------------------+--------------+------------------------------+
    | FF3x:0:0:4E6::/96 |  233.252.0.1 |  FF3X:0:0:04E6::233.252.0.1  |
    |                   |              |            (OR)              |
    |                   |              |    FF3X:0:0:04E6::E9FC:0001  |
    +-------------------+--------------+------------------------------+



4. Well-Known Prefix Usage

   This document doesn't propose any procedure to define the
   usage of the reserved well-known IPv6 Multicast prefix. Any
   solution proposed to solve the transition problem mentioned
   in [I-D.ietf-mboned-v4v6-mcast-ps] may use this reserved
   prefixes.

5. Use Cases

   In this document, we also describe the behavior of one high
   priority scenario with above procedure.







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5.1. IPv4 Receiver and Source connected over IPv6-Only network





   This scenario simply known as 4-6-4 is shown below in Figure
   1.

           +--------+                              +--------+
           |  Host  |                              |  IPv4  |
           |  Rcvr  |                              |   DR   |
           |        |                              |        |
           +--------+                              +--------+
               |                                       |
          IGMP/IPv4 PIM                          IGMP/IPv4 PIM
               |                                       |
               |                                       |
           +--------+          +--------+          +--------+
           |        |   MLD    |  IPv6  |   IPv6   |        |
           |  AFBR1 |----------|  Only  |----------| AFBR2  |
           |        | IPv6 PIM |   Rtr  |    PIM   |        |
           +--------+          +--------+          +--------+
                      Figure 1: 4-6-4 Scenario



   AFBR1 on receiving (S4, G4) or (*, G4) PIM Join or IGMP
   Report will perform the below,



      1. If Upstream is IPv6 PIM neighbor and if G4 is from ASM
        range, should embed the IPv4 multicast group into last
        32 bits of ASM64PREFIX and send PIMv6 JOIN towards
        remote AFBR.
      2. If Upstream is IPv6 PIM router, and if G4 is from SSM
        range, should embed the IPv4 multicast group into last
        32 bits of SSM64PREFIX and send PIMv6 JOIN upstream.


6. Security Considerations

   This document reserves 2 IPv6 Multicast prefixes for Ipv4-
   IPv6 transition purpose. The same security considerations



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   apply as those for [RFC6052]. This document doesn't introduce
   any new security issues.



7. IANA Considerations

   IANA is requested to reserve 2 variable scope IPv6 Multicast
   prefixes for IPv4-IPv6 transition purpose. These should be the
   /96 prefixes;



   SSM Range - FF3x:0:0:04E6::/96

   ASM Range - FF0x:0:0:04E6::/96



8. References

8.1. Normative References

    [RFC2119]  Bradner, S., "Key words for use in RFCs to
             Indicate Requirement Levels", BCP 14, RFC 2119,
             March 1997.

   [RFC5234] Crocker, D. and Overell, P.(Editors), "Augmented
             BNF for Syntax Specifications: ABNF", RFC 5234,
             January 2008.

8.2. Informative References

 [I-D.ietf-mboned-v4v6-mcast-ps]
             Jacquenet, C., Boucadair, M., Lee, Y., Qin, J.,
             Tsou, T., and Q. Sun, "IPv4-IPv6 Multicast: Problem
             Statement and Use Cases", draft-ietf-mboned-v4v6-
             mcast-ps-00 (work in progress), May 2012.
[I-D.ietf-softwire-dslite-multicast]
              Qin, J., Boucadair, M., Jacquenet, C., Lee, Y.,
              and Q. Wang, "Multicast Extension to DS-Lite
              Technique in Broadband Deployments",
              Draft-ietf-softwire-dslite-multicast-02 (work in
              progress), May 2012.



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[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-02 (work in
              progress), April 2012.

   [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.


9. Acknowledgments

   This document was prepared using 2-Word-v2.0.template.dot.

Authors' Addresses

    Stig Venaas
    Cisco Systems, Inc.
    Tasman Drive
    San Jose, CA 95134
    USA
    Email: stig@cisco.com

    Nagendra Kumar
    Cisco Systems
    Cessna Business Park, Sarjapura Marathalli Outer Ring Road
    Bangalore, KARNATAKA  560 087
    India
    Email: naikumar@cisco.com









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