Network Working Group                                          Yiqun Cai
Internet Draft                                    Eric C. Rosen (Editor)
Intended Status: Proposed Standard                     IJsbrand Wijnands
Expires: November 21, 2010                           Cisco Systems, Inc.

                                                            May 21, 2010


  MVPN: Customer IPv6 Using PIM Control Plane and S-PMSI Join Messages


                draft-ietf-l3vpn-mvpn-spmsi-joins-00.txt

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Internet Draft  draft-ietf-l3vpn-mvpn-spmsi-joins-00.txt        May 2010


   described in the Simplified BSD License.


Abstract

   The specification for Multicast Virtual Private Networks (MVPN)
   contains an option that allows the use of PIM as the control protocol
   between provider edge routers.  It also contains an option that
   allows UDP-based "S-PMSI Join" messages to be used to bind particular
   customer multicast flows to particular tunnels through a service
   provider's network.  This document extends the MVPN specification so
   that these options can be used when the customer multicast flows are
   IPv6 flows.



Table of Contents

 1          Specification of requirements  .........................   3
 2          Introduction  ..........................................   3
 3          S-PMSI Joins Binding IPv6 Flows to GRE/IPv4 P-Tunnels  .   3
 3.1        Encoding  ..............................................   4
 3.2        Encapsulation of S-PMSI Joins in UDP Datagrams  ........   5
 4          PE-PE PIM/IPv6 over an IPv4 P-Tunnel  ..................   5
 5          IANA Considerations  ...................................   5
 6          Security Considerations  ...............................   6
 7          Acknowledgments  .......................................   6
 8          Authors' Addresses  ....................................   6
 9          Normative References  ..................................   6

















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1. Specification of requirements

   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 [RFC2119].


2. Introduction

   The Multicast Virtual Private Networks (MVPN) specification [MVPN]
   allows PIM to be used as the control protocol between Provider Edge
   (PE) routers.  This requires PIM messages to be sent through a tunnel
   (a "P-tunnel") from one PE in an MVPN to others in the same MVPN.
   These PIM messages carry customer multicast routing information.
   However, that specification does not cover the case where the
   customer is using IPv6, but the service provider is using P-tunnels
   created by PIM over an IPv4 infrastructure.  The MVPN specification
   also specifies "S-PMSI Join" messages, which are optionally used to
   bind particular customer multicast flows to particular P-tunnels.
   However, the specification does not cover the case where the customer
   flows are IPv6 flows.

   This document extends [MVPN] by adding the specifications for
   handling customer IPv6 multicast flows when a service provider is
   using PE-PE PIM and/or S-PMSI Join messages over an IPv4
   infrastructure.  This document also specifies how to send multiple
   S-PMSI Join messages in a single UDP datagram.

   This document uses terminology defined in [MVPN]: C-Source, C-Group,
   C-flow, P-Group, (C-S,C-G)


3. S-PMSI Joins Binding IPv6 Flows to GRE/IPv4 P-Tunnels

   The S-PMSI Join message is defined in section 7.4.2.2 of [MVPN].
   These messages contain a type field, and [MVPN] defines only "Type 1"
   S-PMSI Joins.  A Type 1 S-PMSI Join may be used to assign a customer
   IPv4 (C-S,C-G) flow to a P-tunnel that is created by PIM/IPv4.
   GRE/IPv4 encapsulation is used to send data or control packets on the
   P-tunnel.

   In this document we define the Type 4 S-PMSI Join.  A Type 4 S-PMSI
   Join may be used to assign a customer IPv6 (C-S,C-G) flow to a
   P-tunnel that is created by PIM/IPv4.  GRE/IPv4 encapsulation is used
   to send data or control packets on the P-tunnel.






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3.1. Encoding

        0                   1                   2                   3
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |     Type      |           Length            |    Reserved     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       |                           C-Source                            |
       |                                                               |
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       |                           C-Group                             |
       |                                                               |
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                           P-Group                             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



   Type (8 bits): 4

   Length (16 bits): 40, the length in octets of the entire S-PMSI Join
   message, including the Type, Length, Reserved, C-Source, C-Group, and
   P-Group fields.

   Reserved (8 bits):  this field SHOULD be zero when transmitted, and
   MUST be ignored when received.

   C-Source (128 bits): the IPv6 address of the traffic source in the
   VPN.

   C-Group (128 bits): the IPv6 group address of the multicast traffic

   P-Group (32 bits): the IPv4 group address identifying the P-tunnel.
   Data packets sent on this tunnel are encapsulated in IPv4 GRE packets
   with this group address in the IP destination address field of the
   outer header.











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3.2. Encapsulation of S-PMSI Joins in UDP Datagrams

   All S-PMSI Joins are encapsulated in UDP datagrams.  A Type 4 S-PMSI
   Join MUST be encapsulated in an IPv6 UDP datagram.  The IPv6 source
   address field of these datagrams SHOULD be the IPv4-mapped IPv6
   address [RFC4291] corresponding to the IPv4 address that the
   originating PE router uses as its source address in the instance of
   PIM that is used to create the specified P-tunnel.

   A single UDP datagram MAY carry multiple S-PMSI Join Messages, as
   many as can fit entirely within it.  If there are multiple S-PMSI
   Joins in a UDP datagram, they MUST be of the same S-PMSI Join type.
   The end of the last S-PMSI Join (as determined by the S-PMSI Join
   length field) MUST coincide with the end of the UDP datagram, as
   determined by the UDP length field.  When processing a received UDP
   datagram that contains one or more S-PMSI Joins, a router MUST
   process all the S-PMSI Joins that fit into the datagram.


4. PE-PE PIM/IPv6 over an IPv4 P-Tunnel

   If a VPN customer is using PIM over IPv6, but the SP is using an IPv4
   infrastructure (i.e., is using an IPv4-based control protocol to
   construct its P-tunnels), then the PE routers will need to originate
   IPv6 PIM control messages.  The IPv6 Source Address field of any such
   IPv6 PIM control message SHOULD be the IPv4-mapped IPv6 address
   [RFC4291] corresponding to the IPv4 address that the originating PE
   router uses as its source address in the instance of PIM that is used
   to create the specified P-tunnel.  If the IPv6 Destination Address
   field is the multicast address ALL-PIM-ROUTERS, the IPv6 form of the
   address (ff02::d) is used.  These IPv6 PIM control messages are of
   course not transmitted natively over the service provider's network,
   but rather are encapsulated in GRE/IPv4.


5. IANA Considerations

   [MVPN] creates an IANA registry for the "S-PMSI Join Message Type
   Field". This document requires that a new value be added to the
   registry:

     - The value 4 should be registered, and its description should read
       "GRE S-PMSI for IPv6 traffic (unaggregated)".








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6. Security Considerations

   There are no additional security considerations beyond those of
   [MVPN].


7. Acknowledgments

   The authors wish to thank DP Ayadevara, Arjen Boers, Rayen Mohanty,
   Rajesh Sharma, and Karthik Subramanian.


8. Authors' Addresses

   Yiqun Cai
   Cisco Systems, Inc.
   170 Tasman Drive
   San Jose, CA, 95134
   E-mail: ycai@cisco.com



   Eric C. Rosen
   Cisco Systems, Inc.
   1414 Massachusetts Avenue
   Boxborough, MA, 01719
   E-mail: erosen@cisco.com



   IJsbrand Wijnands
   Cisco Systems, Inc.
   De kleetlaan 6a Diegem 1831
   Belgium
   E-mail: ice@cisco.com



9. Normative References

   [MVPN] "Multicast in MPLS/BGP IP VPNs", Rosen, Aggarwal, et. al.,
   draft-ietf-l3vpn-2547bis-mcast-10.txt, January 2010

   [RFC2119] "Key words for use in RFCs to Indicate Requirement
   Levels.", Bradner, March 1997

   [RFC4291] "IPv6 Addressing Architecture", Hinden, Deering, February
   2006



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