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rfc:rfc6625

Internet Engineering Task Force (IETF) E. Rosen, Ed. Request for Comments: 6625 Cisco Systems, Inc. Updates: 6514 Y. Rekhter, Ed. Category: Standards Track Juniper Networks, Inc. ISSN: 2070-1721 W. Henderickx

                                                        Alcatel-Lucent
                                                                R. Qiu
                                                                Huawei
                                                              May 2012
          Wildcards in Multicast VPN Auto-Discovery Routes

Abstract

 In Multicast Virtual Private Networks (MVPNs), customer multicast
 flows are carried in "tunnels" through a service provider's network.
 The base specifications for MVPN define BGP multicast VPN "auto-
 discovery routes" and specify how to use an auto-discovery route to
 advertise the fact that an individual customer multicast flow is
 being carried in a particular tunnel.  However, those specifications
 do not provide a way to specify, in a single such route, that
 multiple customer flows are being carried in a single tunnel.  Those
 specifications also do not provide a way to advertise that a
 particular tunnel is to be used by default to carry all customer
 flows, except in the case where that tunnel is joined by all the
 provider edge routers of the MVPN.  This document eliminates these
 restrictions by specifying the use of "wildcard" elements in the
 customer flow identifiers.  With wildcard elements, a single auto-
 discovery route can refer to multiple customer flows or even to all
 customer flows.

Status of This Memo

 This is an Internet Standards Track document.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 5741.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 http://www.rfc-editor.org/info/rfc6625.

Rosen, et al. Standards Track [Page 1] RFC 6625 Wildcards in MVPN A-D Routes May 2012

Copyright Notice

 Copyright (c) 2012 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
 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. Terminology ................................................3
    1.2. Wildcards in S-PMSI A-D Routes .............................5
    1.3. Use Cases ..................................................5
 2. Encoding of Wildcards ...........................................7
 3. Finding the Matching S-PMSI A-D Route ...........................8
    3.1. Finding the Match for Data Transmission ....................8
    3.2. Finding the Match for Data Reception .......................9
         3.2.1. Finding the Match for (C-S,C-G) .....................9
         3.2.2. Finding the Wildcard Match for (C-*,C-G) ............9
 4. Procedures for S-PMSI A-D Routes with Wildcards ................10
    4.1. Procedures for All Kinds of Wildcards .....................10
    4.2. Procedures for (C-*,C-G) S-PMSI A-D Routes ................11
    4.3. Procedures for (C-S,C-*) S-PMSI A-D Routes ................12
    4.4. Procedures for (C-*,C-*) S-PMSI A-D Routes ................13
 5. Security Considerations ........................................15
 6. Acknowledgments ................................................15
 7. Normative References ...........................................15

Rosen, et al. Standards Track [Page 2] RFC 6625 Wildcards in MVPN A-D Routes May 2012

1. Introduction

 In Multicast Virtual Private Networks (MVPNs), customer multicast
 flows are carried in tunnels through a service provider's network.
 The base specifications for MVPN define BGP multicast VPN
 "auto-discovery routes" and specify how to use an auto-discovery
 route to advertise the fact that an individual customer multicast
 flow is being carried in a particular tunnel.  However, those
 specifications do not provide a way to specify, in a single such
 route, that multiple customer flows are being carried in a single
 tunnel.  Those specifications also do not provide a way to advertise
 that a particular tunnel is to be used by default to carry all
 customer flows, except in the case where that tunnel is joined by all
 the provider edge routers of the MVPN.  This document eliminates
 these restrictions by specifying the use of "wildcard" elements in
 the customer flow identifiers.  With wildcard elements, a single
 auto-discovery route can refer to multiple customer flows or even to
 all customer flows.

1.1. Terminology

 This document uses terminology from [MVPN] and, in particular, uses
 the prefixes "C-" and "P-", as specified in Section 3.1 of [MVPN], to
 distinguish addresses in the "customer address space" from addresses
 in the "provider address space".  The following terminology and
 acronyms are particularly important in this document:
  1. MVPN
      Multicast Virtual Private Network -- a VPN [L3VPN] in which
      multicast service is offered.
  1. VRF
      VPN Routing and Forwarding table [L3VPN].
  1. SP
      Service Provider.
  1. P-tunnel
      A tunnel through the network of one or more SPs.
  1. C-S
      Multicast Source.  A multicast source address, in the address
      space of a customer network.

Rosen, et al. Standards Track [Page 3] RFC 6625 Wildcards in MVPN A-D Routes May 2012

  1. C-G
      Multicast Group.  A multicast group address (destination
      address) in the address space of a customer network.
  1. C-multicast flow or C-flow
      A customer multicast flow.  Each C-flow is identified by the
      ordered pair (source address, group address), where each address
      is in the customer's address space.  The identifier of a
      particular C-flow is usually written as (C-S,C-G).
  1. RP
      A "Rendezvous Point", as defined in [PIM].
  1. C-RP
      A Rendezvous Point whose address is in the customer's address
      space.
  1. Selective P-tunnel
      A P-tunnel that is joined only by Provider Edge (PE) routers
      that need to receive one or more of the C-flows that are
      traveling through that P-tunnel.
  1. Inclusive P-tunnel
      A P-tunnel that is joined by all PE routers that attach to sites
      of a given MVPN.
  1. S-PMSI A-D route
      Selective Provider Multicast Service Interface Auto-Discovery
      route.  Carried in BGP Update messages, these routes are used to
      advertise the fact that particular C-flows are bound to (i.e.,
      are traveling through) particular P-tunnels.
 Familiarity with multicast concepts and terminology [PIM] is also
 presupposed.
 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].

Rosen, et al. Standards Track [Page 4] RFC 6625 Wildcards in MVPN A-D Routes May 2012

1.2. Wildcards in S-PMSI A-D Routes

 As specified in [MVPN] and [MVPN-BGP], an S-PMSI A-D route advertises
 that a particular C-flow is bound to a particular selective P-tunnel.
 The identifier of the specified C-flow, e.g., (C-S,C-G), is encoded
 into the Network Layer Reachability Information (NLRI) of the S-PMSI
 A-D route.  The identifier of the specified P-tunnel is encoded into
 an attribute (the "PMSI Tunnel Attribute") of the S-PMSI A-D route.
 Each S-PMSI A-D route thus specifies a single C-flow.  To bind
 multiple C-flows to a single P-tunnel, it is necessary to advertise
 one S-PMSI A-D route for each C-flow, specifying the same P-tunnel in
 each such route.
 This document defines OPTIONAL extensions to the procedures and
 encodings specified in [MVPN] and [MVPN-BGP].  These extensions
 enable a single S-PMSI A-D route to advertise that multiple
 C-multicast flows are bound to a single P-tunnel.
 The extensions specified in this document are based on the notion of
 allowing the NLRI of an S-PMSI A-D route to contain a "wildcard".  In
 the NLRI encoding, a wildcard can replace the C-S, the C-G, or both.
 We use the notation "C-*" to denote a wildcard.  The extensions allow
 the NLRI to encode three kinds of wildcards: (C-*,C-*), (C-S,C-*),
 and (C-*,C-G).
 By using wildcards, a PE may be able to reduce the number of S-PMSI
 A-D routes it originates, thereby improving the scalability of the
 control plane.  There is, however, no impact on data plane
 scalability, as the number of P-tunnels is not reduced.
 Encoding and detailed procedures are specified in subsequent sections
 of this document.

1.3. Use Cases

 There are a number of situations in which it can be useful to use
 wildcards in the NLRI of an S-PMSI A-D route.
  1. Using a selective P-tunnel as the default tunnel.
      There are procedures in [MVPN] and [MVPN-BGP] that allow a PE to
      advertise that it is going to use an inclusive P-tunnel as the
      P-tunnel on which it will transmit all C-flows by "default".
      However, those documents do not provide any way for a PE to
      advertise that it is going to use a selective P-tunnel as the
      P-tunnel on which it will transmit all C-flows by "default".
      Using the extensions defined in this document, a PE can

Rosen, et al. Standards Track [Page 5] RFC 6625 Wildcards in MVPN A-D Routes May 2012

      advertise that it is going to use a selective P-tunnel as its
      default P-tunnel.  It does so by advertising an S-PMSI A-D route
      whose NLRI contains (C-*,C-*).
  1. Binding multiple C-flows traveling along a customer's Protocol

Independent Multicast - Sparse Mode (PIM-SM) shared tree to a

      single P-tunnel.
      A PE router may be connected to an MVPN site that contains a
      customer RP (C-RP).  The C-RP may be the root of one or more
      shared trees.  In multicast terminology, these are known as
      (*,G) trees.  By advertising a single S-PMSI A-D route whose
      NLRI contains the (C-*,C-G) wildcard, the PE can bind all the
      C-flows traveling along a customer's (*,G) tree to a single
      P-tunnel.  This use case applies only when C-G is a
      non-bidirectional ASM (Any Source Multicast) group.
  1. Binding multiple C-flows with the same C-group address to a

single P-tunnel, even if each such C-flow is traveling along a

      customer's PIM source tree.
      A PE router may be connected to an MVPN site containing several
      multicast sources that are all sending to a common multicast
      group, along a customer's PIM source trees.  Alternatively, the
      PE may be connected to several sites, each containing at least
      one source sending to the common multicast group.  By
      advertising a single S-PMSI A-D route whose NLRI contains
      (C-*,C-G), the PE can bind these C-flows to a single P-tunnel.
      This use case applies only when the C-group is a
      non-bidirectional ASM group.
  1. Binding multiple C-flows with the same C-group address to a

single P-tunnel, when those C-flows are traveling along a

      customer's BIDIR-PIM shared tree.
      This use case applies only when the C-group is a BIDIR-PIM
      group.
  1. Binding multiple C-flows from a given C-source to a given

P-tunnel, irrespective of whether those C-flows all have the

      same C-group address.
      This can be useful when the C-group addresses are SSM (Single
      Source Multicast) addresses.  Suppose, for example, that a given
      source transmits multiple "channels" of information, each with

Rosen, et al. Standards Track [Page 6] RFC 6625 Wildcards in MVPN A-D Routes May 2012

      its own C-group address.  It may be desirable to bind all these
      channels to a single P-tunnel, without having to advertise an
      S-PMSI A-D route for each one.
 Of course, a specific C-flow, (C-S,C-G), can always be assigned
 individually to a particular P-tunnel by advertising an S-PMSI A-D
 route whose NLRI contains (C-S,C-G).
 In Section 4, we will sometimes speak of an S-PMSI A-D route being
 ignored.  When we say the route is "ignored", we do not mean that its
 normal BGP processing is not done, but that the route is not
 considered when determining which P-tunnel to use when receiving
 multicast data, and that the MPLS label values it conveys are not
 used.  We will use "ignore" in quotes to indicate this meaning.
 This document provides procedures only for the case where the
 P-tunnels are "unidirectional", i.e., point-to-multipoint.  The use
 of "bidirectional" (multipoint-to-multipoint) P-tunnels is outside
 the scope of this document.

2. Encoding of Wildcards

 Per [MVPN-BGP] Section 4.3, the MCAST-VPN NLRI in an S-PMSI A-D route
 is encoded as follows:
              +-----------------------------------+
              |      RD   (8 octets)              |
              +-----------------------------------+
              | Multicast Source Length (1 octet) |
              +-----------------------------------+
              |  Multicast Source (variable)      |
              +-----------------------------------+
              |  Multicast Group Length (1 octet) |
              +-----------------------------------+
              |  Multicast Group   (variable)     |
              +-----------------------------------+
              |   Originating Router's IP Addr    |
              +-----------------------------------+
 where the "source length" and "group length" fields always have a
 non-zero value.  This document specifies that a "zero-length" source
 or group represents the corresponding wildcard.  Specifically,
  1. A source wildcard is encoded as a zero-length source field.

That is, the "multicast source length" field contains the value

      0x00, and the "multicast source" field is omitted.

Rosen, et al. Standards Track [Page 7] RFC 6625 Wildcards in MVPN A-D Routes May 2012

  1. A group wildcard is encoded as a zero-length group field. That

is, the "multicast group length" field contains the value 0x00,

      and the "multicast group" field is omitted.

3. Finding the Matching S-PMSI A-D Route

 This section gives the precise rules for determining the S-PMSI A-D
 route that is "matched" by a given (C-S,C-G) or (C-*,C-G).  The
 procedures in Section 4 will make use of the matching rules defined
 in this section.
 All matching rules assume the context of a given VRF at a given PE.
 The rules that a PE applies to find the S-PMSI A-D route that matches
 a (C-S,C-G) C-flow that it needs to transmit are slightly different
 than the rules it applies to find the S-PMSI A-D route that matches a
 (C-S,C-G) C-flow that it needs to receive.  These rules are specified
 in Sections 3.1 and 3.2, respectively.
 The S-PMSI A-D route that is matched by a given (C-S,C-G) may change
 over time, as the result of S-PMSI A-D routes being withdrawn or as a
 result of new S-PMSI A-D routes being originated and/or advertised.
 In particular, if (C-S,C-G) matches an S-PMSI A-D route whose NLRI
 contains (C-*,C-*), the origination or reception of an S-PMSI A-D
 route whose NLRI contains (C-S,C-G) may cause (C-S,C-G) to match the
 latter route instead.  Note also that the S-PMSI A-D route that
 matches a given (C-S,C-G) is independent of the order in which the
 routes were originated or received.

3.1. Finding the Match for Data Transmission

 Consider a given PE; call it PE1.  At any given time, for a given VRF
 at PE1, there is a (possibly empty) set of S-PMSI A-D routes that PE1
 has originated and advertised, but not withdrawn.  We will refer to
 these routes as "currently originated" by PE1.  Suppose that PE1
 needs to transmit a particular C-flow (C-S,C-G) to one or more other
 PEs.  We use the following algorithm to find the S-PMSI A-D route
 that the C-flow "matches":
  1. If there is an S-PMSI A-D route currently originated by PE1,

whose NLRI contains (C-S,C-G), the (C-S,C-G) C-flow matches that

      route.
  1. Otherwise, if there is an S-PMSI A-D route currently originated

by PE1, whose NLRI contains (C-S,C-*), AND if C-G is an SSM

      group address, the (C-S,C-G) C-flow matches that route.

Rosen, et al. Standards Track [Page 8] RFC 6625 Wildcards in MVPN A-D Routes May 2012

  1. Otherwise, if there is an S-PMSI A-D route currently originated

by PE1, whose NLRI contains (C-*,C-G), AND if C-G is an ASM

      group address, the (C-S,C-G) C-flow matches that route.
  1. Otherwise, if there is an S-PMSI A-D route currently originated

by PE1, whose NLRI contains (C-*,C-*), the (C-S,C-G) C-flow

      matches that route.

3.2. Finding the Match for Data Reception

 We refer to an S-PMSI A-D route as being "installed" (in a given VRF)
 if it has been selected by the BGP decision process as the preferred
 route for its NLRI.
 An S-PMSI A-D route is considered to be "originated by a given PE" if
 that PE's IP address is contained in the "Originating Router's IP
 Address" field in the MCAST-VPN NLRI of the route.

3.2.1. Finding the Match for (C-S,C-G)

 Suppose that a PE router (call it PE1) needs to receive (C-S,C-G),
 and that PE1 has chosen another PE router (call it PE2) as the
 "upstream PE" [MVPN] for that flow.
  1. If there is an installed S-PMSI A-D route originated by PE2,

whose NLRI contains (C-S,C-G), then (C-S,C-G) matches that

      route.
  1. Otherwise, if there is an installed S-PMSI A-D route originated

by PE2, whose NLRI contains (C-S,C-*), AND if C-G is an SSM

      multicast group address, then (C-S,C-G) matches that route.
  1. Otherwise, if there is an installed S-PMSI A-D route originated

by PE2, whose NLRI contains (C-*,C-G), AND if C-G is an ASM

      multicast group address, then (C-S,C-G) matches that route.
  1. Otherwise, if there is an installed S-PMSI A-D route originated

by PE2, whose NLRI contains (C-*,C-*), then (C-S,C-G) matches

      that route.

3.2.2. Finding the Wildcard Match for (C-*,C-G)

 Suppose that a PE router (call it PE1) needs to receive (C-*,C-G)
 traffic.  Note that even if (C-*,C-G) matches a non-wildcard S-PMSI
 A-D route (as detailed in Section 12.3 of [MVPN-BGP]), it may also
 match one or more wildcard S-PMSI A-D routes, as specified below.

Rosen, et al. Standards Track [Page 9] RFC 6625 Wildcards in MVPN A-D Routes May 2012

 If on PE1 there is an installed S-PMSI A-D route originated by PE2,
 whose NLRI contains (C-*,C-G), then (C-*,C-G) matches this route if
 one of the following conditions holds:
  1. PE1 determines that PE2 is the "upstream" PE [MVPN] for the C-RP

of C-G, or

  1. PE1 has installed one or more Source Active A-D routes for C-G

originated by PE2, and for at least one of these routes, PE1

      does not have a corresponding (C-S,C-G) state, or
  1. C-G is a BIDIR-PIM group, or
  1. Source Active A-D routes are not being used.
 If (C-*,C-G) does not match a (C-*,C-G) S-PMSI A-D route from PE2,
 but PE1 has an installed (C-*,C-*) S-PMSI A-D route from PE2, then
 (C-*,C-G) matches the (C-*,C-*) route if one of the following
 conditions holds:
  1. PE1 determines that PE2 is the "upstream" PE [MVPN] for the C-RP

of C-G, or

  1. PE1 has installed one or more Source Active A-D routes for C-G

originated by PE2, and for at least one of these routes, PE1

      does not have a corresponding (C-S,C-G) state, or
  1. C-G is a BIDIR-PIM group, or
  1. Source Active A-D routes are not being used.

4. Procedures for S-PMSI A-D Routes with Wildcards

4.1. Procedures for All Kinds of Wildcards

 This document defines procedures for the following uses of the
 wildcard in the NLRI of an S-PMSI A-D route:
  1. (C-*,C-G): Source wildcard, group specified.
  1. (C-S,C-*): Source specified, group wildcard.
  1. (C-*,C-*): Source wildcard, group wildcard.
 All other wildcard functionality is outside the scope of this
 document.

Rosen, et al. Standards Track [Page 10] RFC 6625 Wildcards in MVPN A-D Routes May 2012

 The ability to originate S-PMSI A-D routes with a particular kind of
 wildcard is OPTIONAL.  However, if a PE has the ability to originate
 S-PMSI A-D routes with a particular kind of wildcard, it MUST have
 the ability to interpret and correctly process S-PMSI A-D routes with
 that kind of wildcard, and it SHOULD have the ability to interpret
 and correctly process all three kinds of wildcards.
 For a given MVPN, A PE MUST NOT originate S-PMSI A-D routes with a
 particular kind of wildcard unless it is known a priori that all PEs
 attached to that MVPN have the ability to interpret and correctly
 process that kind of wildcard.
 The criteria for originating and withdrawing S-PMSI A-D routes with
 wildcards are local to the originating PE.
 As specified in [MVPN-BGP], an S-PMSI A-D route is carried in the
 NLRI field of an MP_REACH_NLRI attribute (see [BGP-MP]).  Every
 S-PMSI A-D route has a particular address family (IPv4 or IPv6), as
 specified in the Address Family Identifier (AFI) field of the
 MP_REACH_NLRI attribute.  A wildcard in a particular S-PMSI A-D route
 always refers only to multicast flows of that same address family.
 The procedures specified in this document apply only when the PMSI
 Tunnel Attribute of an S-PMSI A-D route specifies a "unidirectional"
 P-tunnel.  The use of "bidirectional" P-tunnels (e.g., Multipoint-to-
 Multipoint Label Switched Paths, BIDIR-PIM trees) is outside the
 scope of this document.
 In the following sections, an S-PMSI A-D route whose NLRI contains
 (C-*,C-G), (C-S,C-*), or (C-*,C-*) will be referred to as a
 "(C-*,C-G) route", a "(C-S,C-*) route", or a "(C-*,C-*)" route,
 respectively.

4.2. Procedures for (C-*,C-G) S-PMSI A-D Routes

 This document specifies the use of (C-*,C-G) S-PMSI A-D routes only
 in the case where C-G is an ASM group address.  Use of (C-*,C-G)
 S-PMSI A-D routes where C-G is an SSM group address is outside the
 scope of this document.  If a PE receives a (C-*,C-G) S-PMSI A-D
 route, and the PE can determine that C-G is an SSM group address, the
 PE SHOULD "ignore" this S-PMSI A-D route.
 By default, the set of Route Targets carried by a (C-*,C-G) S-PMSI
 A-D route originated by a given VRF is the same as the set of Route
 Targets carried in the (unicast) VPN-IP routes that originated from
 that VRF.  An implementation MUST allow the set of Route Targets

Rosen, et al. Standards Track [Page 11] RFC 6625 Wildcards in MVPN A-D Routes May 2012

 carried by the (C-*,C-G) S-PMSI A-D route to be specified by
 configuration.  In the absence of a configured set of Route Targets,
 the route MUST carry the default set of Route Targets.
 If a PE needs to transmit packets of a (C-S,C-G) C-flow, and if
 (C-S,C-G) matches a (C-*,C-G) S-PMSI A-D route according to the rules
 of Section 3.1, then the PE MUST use the P-tunnel advertised in this
 route for transmitting that C-flow.  (Note that it is impossible for
 a given (C-S,C-G) to match both a (C-*,C-G) wildcard and a (C-S,C-*)
 wildcard.)
 If PIM is being used as the PE-PE control protocol, then if the PE
 has (C-*,C-G) and/or (C-S,C-G) state that matches (according to the
 procedures of Section 3.2) an S-PMSI A-D route, the PE MUST join the
 P-tunnel specified in the PMSI Tunnel Attribute of that route.
 If BGP is being used as the PE-PE control protocol, then
  1. If a given PE has currently originated a C-multicast Shared Tree

Join for (C-*,C-G), and if (C-*,C-G) matches a (C-*,C-G) S-PMSI

      A-D route, then the PE applies the procedures of Section 12.3
      ("Receiving S-PMSI A-D Routes by PEs") of [MVPN-BGP] to that
      S-PMSI A-D route.
  1. Otherwise (the given PE does not have a currently originated

C-multicast Shared Tree Join for (C-*,C-G)), if there are one or

      more values of C-S for which the PE has a currently originated
      Source Tree Join C-multicast route for (C-S,C-G), the PE MUST
      join the tunnels advertised by the S-PMSI A-D routes that match
      (according to Section 3.2) each such (C-S,C-G).
  1. Otherwise, the PE "ignores" the route.

4.3. Procedures for (C-S,C-*) S-PMSI A-D Routes

 This document covers the use of (C-S,C-*) S-PMSI A-D routes for only
 the C-multicast flows where C-G is an SSM group address.  Use of
 (C-S,C-*) S-PMSI A-D routes for other C-multicast flows is outside
 the scope of this document.  Specifically, if a PE receives a
 (C-S,C-*) S-PMSI A-D route, and the PE can determine that C-G is not
 an SSM group address, the PE SHOULD "ignore" this S-PMSI A-D route.
 By default, the set of Route Targets carried by a (C-S,C-*) S-PMSI
 A-D route originated by a given VRF is an intersection between the
 set of Route Targets carried in the Intra-AS I-PMSI A-D route that
 originated from that VRF, and the set of Route Targets carried by the
 unicast VPN-IP route to C-S originated from that VRF.  An
 implementation MUST allow the set of Route Targets carried by the

Rosen, et al. Standards Track [Page 12] RFC 6625 Wildcards in MVPN A-D Routes May 2012

 (C-S,C-*) S-PMSI A-D route to be specified by configuration.  In the
 absence of a configured set of Route Targets, the route MUST carry
 the default set of Route Targets.
 If a PE needs to transmit packets of a (C-S,C-G) C-flow, and if
 (C-S,C-G) matches a (C-S,C-*) S-PMSI A-D route according to the rules
 of Section 3.1, then the PE MUST use the P-tunnel advertised in this
 route for transmitting that C-flow.  (Note that it is impossible for
 a given (C-S,C-G) to match both a (C-*,C-G) wildcard and a (C-S,C-*)
 wildcard.)
 If PIM is being used as the PE-PE control protocol for distributing
 C-multicast routing, and if a given PE needs to receive a (C-S,C-G)
 flow, and if (C-S,C-G) matches the (C-S,C-*) S-PMSI A-D route
 (according to the procedures of Section 3.2), then the PE MUST join
 the P-tunnel specified in the PMSI Tunnel Attribute of that route.
 If BGP is being used as the PE-PE control protocol for distributing
 C-multicast routing, and if there is some (C-S,C-G) such that (a) the
 PE has a currently originated (C-S,C-G) Source Tree Join C-multicast
 route, AND (b) the given (C-S,C-G) matches (according to the
 procedures of Section 3.2) a (C-S,C-*) S-PMSI A-D route, then PE1
 applies the procedures of Section 12.3 ("Receiving S-PMSI A-D Routes
 by PEs") of [MVPN-BGP] to the matching S-PMSI A-D route.

4.4. Procedures for (C-*,C-*) S-PMSI A-D Routes

 (C-*,C-*) S-PMSI A-D routes are used when, for a given MVPN, a PE has
 a policy not to use an I-PMSI for carrying multicast data traffic
 originated in the MVPN's site(s) connected to that PE.  When the
 (C-*,C-*) wildcard is used together with BGP C-multicast routing,
 this results in the "S-PMSI only" model, where no I-PMSIs are used at
 all for the given MVPN.
 A (C-*,C-*) S-PMSI A-D route is originated for a given MVPN by a
 given PE only if that PE has been provisioned with the policy to
 do so.
 When so provisioned, the PE MAY originate the (C-*,C-*) S-PMSI A-D
 route as soon as it is enabled to support the given MVPN.
 Alternatively, the PE MAY delay originating the route until one of
 the following conditions holds:
  1. The PE-PE protocol for distributing C-multicast routing is PIM,

and for the given MVPN, the PE has some (C-S,C-G) or (C-*,C-G)

      state for which the upstream interface is one of the VRF
      interfaces for the given MVPN.

Rosen, et al. Standards Track [Page 13] RFC 6625 Wildcards in MVPN A-D Routes May 2012

  1. The PE-PE protocol for distributing C-multicast routing is BGP,

and the given PE has received and installed either of the

      following:
  • a Source Tree Join C-multicast route, with the C-S contained

in the route's NLRI being reachable via one of the given

        MVPN's VRF interfaces, or
  • a Shared Tree Join C-multicast route, with the C-RP carried in

that route being reachable via one of the given MVPN's VRF

        interfaces.
 By default, the set of Route Targets carried by a (C-*,C-*) S-PMSI
 A-D route originated from a given VRF is the same as the set of Route
 Targets carried in the VPN-IP unicast routes originated from that
 VRF.  An implementation MUST allow the set of Route Targets carried
 by the (C-*,C-*) S-PMSI A-D route to be specified by configuration.
 In the absence of a configured set of Route Targets, the route MUST
 carry the default set of Route Targets, as specified above.
 If a PE needs to transmit packets of a (C-S,C-G) C-flow, and if
 (C-S,C-G) matches a (C-*,C-*) S-PMSI A-D route according to the rules
 of Section 3.1, then the PE MUST use the P-tunnel advertised in this
 route for transmitting that C-flow.  (Note that it is impossible for
 a given (C-S,C-G) to match both a (C-*,C-*) wildcard and any other
 wildcard.)
 If PIM is being used as the PE-PE control protocol for distributing
 C-multicast routing, and if a given PE, say PE1, needs to receive a
 (C-S,C-G) flow, and if (C-S,C-G) matches the (C-*,C-*) S-PMSI A-D
 route (according to the procedures of Section 3.2), then PE1 MUST
 join the P-tunnel specified in the PMSI Tunnel Attribute of that
 route.
 If BGP is being used as the PE-PE control protocol for distributing
 C-multicast routing, then if (and only if) one of the following
 conditions holds, the PE applies the procedures of Section 12.3
 ("Receiving S-PMSI A-D Routes by PEs") of [MVPN-BGP] to the matching
 S-PMSI A-D route.  The conditions are as follows:
  1. The PE has a currently originated C-multicast Source Tree Join

route for (C-S,C-G) that matches (according to the procedures of

      Section 3.2) the (C-*,C-*) S-PMSI A-D route, or
  1. The PE has a currently originated a C-multicast Shared Tree Join

route for (C-*,C-G) that matches (according to the procedures of

      Section 3.2) the (C-*,C-*) S-PMSI A-D route.

Rosen, et al. Standards Track [Page 14] RFC 6625 Wildcards in MVPN A-D Routes May 2012

5. Security Considerations

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

6. Acknowledgments

 The authors wish to thank Arjen Boers, Dongling Duan, Apoorva Karan,
 Thomas Morin, Keyur Patel, Karthik Subramanian, and Kurt Windisch for
 many helpful discussions.

7. Normative References

 [BGP-MP]    Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
             "Multiprotocol Extensions for BGP-4", RFC 4760,
             January 2007.
 [L3VPN]     Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
             Networks (VPNs)", RFC 4364, February 2006.
 [MVPN]      Rosen, E., Ed., and R. Aggarwal, Ed., "Multicast in
             MPLS/BGP IP VPNs", RFC 6513, February 2012.
 [MVPN-BGP]  Aggarwal, R., Rosen, E., Morin, T., and Y.  Rekhter, "BGP
             Encodings and Procedures for Multicast in MPLS/BGP IP
             VPNs", RFC 6514, February 2012.
 [PIM]       Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
             "Protocol Independent Multicast - Sparse Mode (PIM-SM):
             Protocol Specification (Revised)", RFC 4601, August 2006.
 [RFC2119]   Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

Rosen, et al. Standards Track [Page 15] RFC 6625 Wildcards in MVPN A-D Routes May 2012

Authors' Addresses

 Rahul Aggarwal
 Arktan
 EMail: raggarwa_1@yahoo.com
 Yiqun Cai
 Microsoft
 1065 La Avenida
 Mountain View, CA  94043
 EMail: yiqunc@microsoft.com
 Wim Henderickx
 Alcatel-Lucent
 EMail: wim.henderickx@alcatel-lucent.be
 Praveen Muley
 Alcatel-Lucent
 EMail: Praveen.Muley@alcatel-lucent.com
 Ray (Lei) Qiu
 2330 Central Expressway
 Santa Clara, CA  95050
 USA
 EMail: rayq@huawei.com
 Yakov Rekhter (editor)
 Juniper Networks
 1194 North Mathilda Ave.
 Sunnyvale, CA  94089
 EMail: yakov@juniper.net

Rosen, et al. Standards Track [Page 16] RFC 6625 Wildcards in MVPN A-D Routes May 2012

 Eric C. Rosen (editor)
 Cisco Systems, Inc.
 1414 Massachusetts Avenue
 Boxborough, MA  01719
 EMail: erosen@cisco.com
 IJsbrand Wijnands
 Cisco Systems, Inc.
 De kleetlaan 6a Diegem 1831
 Belgium
 EMail: ice@cisco.com

Rosen, et al. Standards Track [Page 17]

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