





L3VPN Working Group                                            Yiqun Cai
Internet Draft                                    Eric C. Rosen (Editor)
Intended Status: Proposed Standard                     IJsbrand Wijnands
Expires: May 8, 2011                                 Cisco Systems, Inc.

                                                        November 8, 2010


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


                draft-ietf-l3vpn-mvpn-spmsi-joins-02.txt

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 messages, known as S-PMSI ("Selective Provider
   Multicast Service Interface") 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.


Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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Copyright and License Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors. All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   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          Specification of requirements  .........................   3
 2          Introduction  ..........................................   3
 3          S-PMSI Joins Binding IPv6 Flows to GRE/IPv4 P-Tunnels  .   3
 3.1        Encoding  ..............................................   5
 3.2        Encapsulation of S-PMSI Joins in UDP Datagrams  ........   6
 4          PE-PE PIM/IPv6 over an IPv4 P-Tunnel  ..................   6
 5          IANA Considerations  ...................................   6
 6          Security Considerations  ...............................   7
 7          Acknowledgments  .......................................   7
 8          Authors' Addresses  ....................................   7
 9          Normative References  ..................................   7

















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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]
   defines the notion of a "PMSI" (Provider Multicast Service
   Interface), and specifies how a PMSI can be instantiated by various
   kinds of tunnels through a service provider's network ("P-tunnels").
   It also specifies the procedures for using PIM ("Protocol Independent
   Multicast", [RFC4601]) as the control protocol between Provider Edge
   (PE) routers.  When PIM is used as the control protocol, PIM messages
   are sent through a P-tunnel from one PE in an MVPN to others in the
   same MVPN.  These PIM messages carry customer multicast routing
   information.  However, [MVPN] 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 (Selective 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 specification 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.  To
   transmit data or control packets over such a P-tunnel, the packets
   are encapsulated in GRE ("Generic Routing Encapsulation") within
   IPv4, as specified in section 12 of [MVPN].

   In this document we define the Type 4 S-PMSI Join.  A Type 4 S-PMSI



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   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 [RFC768].  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 (Service
   Provider) 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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   [RFC4601] "Protocol Independent Multicast - Sparse Mode (PIM-SM)",
   Fenner, Handley, Holbrook, Kouvelas, August 2006, RFC 4601

   [RFC768] "User Datagram Protocol", Postel, August 1980, RFC 768















































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