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Versions: 00

Internet Engineering Task Force                                  H. Jeng
Internet-Draft                                                      AT&T
Updates: 5575 (if approved)                                      J. Haas
Intended status: Standards Track                              Y. Rekhter
Expires: August 8, 2014                                         J. Zhang
                                                        Juniper Networks
                                                        February 4, 2014


                Multicast Distribution Control Signaling
                         draft-ietf-idr-mdcs-00

Abstract

   This document describes a mechanism whereby the BGP Flow
   Specification NLRI format may be utilized to distribute multicast
   Control Plane filters.  This mechanism is called Multicast
   Distribution Control Signaling (MDCS).

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
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   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 August 8, 2014.

Copyright Notice

   Copyright (c) 2014 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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   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of



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


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Specification of Requirements . . . . . . . . . . . . . . . . . 3
     2.1.  Multicast Distribution Control Signaling  . . . . . . . . . 3
     2.2.  An example of configuration on ERs  . . . . . . . . . . . . 6
   3.  Summary of Updates to BGP Flowspec  . . . . . . . . . . . . . . 7
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 7
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 7
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . . . 7
     7.2.  Informative References  . . . . . . . . . . . . . . . . . . 8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 8

































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1.  Introduction

   Consider a content provider that wants to deliver a particular
   content to a set of customers/subscribers, where the provider and the
   subscribers are connected by an IP service provider and the content
   is distributed using multicast connectivity.  The content provider
   may wish to restrict delivery of the content to a subset of the
   subscribers in a centralized fashion.

   For the purpose of this document we assume that a content provider
   consists of one or more Content Servers, and one or more Content
   Distribution Controllers.  While this document assumes communication
   between Content Servers and Content Distribution Controllers, the
   procedures for implementing such communication is outside the scope
   of this document.

   Content Servers are connected to one or more IP service providers
   (ISPs) that are offering multicast delivery of the content to the
   subscribers of the content provider.  Content providers use these
   ISPs to deliver content to their subscribers.

   Subscribers are connected to the Edge Routers (ERs) of the ISP.  Note
   that the multicast connectivity service provided by the ISP extends
   all the way to the ERs.  Such service could be provided by either
   deploying IP multicast natively, or with some tunneling mechanism
   like AMT, or by a combination of both within the ISP.  However,
   between the ERs and the subscribers there may, or may not be
   multicast connectivity.

   For further information, see [geo-dist].


2.  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 RFC 2119 [RFC2119].

2.1.  Multicast Distribution Control Signaling

   Multicast distribution control signaling is intended to enforce
   exclusion/inclusion policies of a content provider, and specifically
   to prevent a subscriber from accessing a particular multicast channel
   carrying a particular content provided by the content provider if the
   subscriber obtained the information about this channel through some
   illegitimate means.

   Multicast distribution control signaling for a particular content is



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   originated by Content Distribution Controller(s), and uses BGP Flow
   Spec [RFC5575] as follows:

   For a particular content carried over a particular (S, G) multicast
   flow the Content Distribution Controller responsible for that content
   originates a BGP Flow Spec route.  This route is carried using BGP
   multi-protocol capabilities [RFC4760] with AFI 1 (for IPv4) or 2 (for
   IPv6), and the MCAST-FLOWSPEC SAFI.  The NLRI of the route carries S
   in the Source Prefix component (with length of 32 for IPv4 or 128 for
   IPv6), and G in the Destination Prefix component (with length of 32
   for IPv4 of 128 for IPv6).

   This route is ultimately propagated to the ER of the ISP connected to
   the content provider.

   An ER that receives BGP Flow Spec routes carrying the multicast
   distribution control information applies it to PIM and/or IGMP
   messages the ER receives from the subscribers connected to that ER.
   (Note that such IGMP messages may be encapsulated in MDT messages.)
   Specifically, the ER, based on the information received in the BGP
   Flow Spec routes, decides whether to accept (or reject) a particular
   PIM or IGMP Join received on one of its subscriber's ports, as
   follows:

   As a Content Distribution Controller originates a BGP Flow Spec route
   for a particular (S, G) multicast flow, such a route will carry one
   or more Route Targets [RFC4360], which will ultimately control
   inclusion/exclusion of that flow on individual ports of ERs that
   receive this route.

   Each subscriber port on an ER is associated with one or more zones.
   For each zone that a port belongs to, the port is provisioned with
   two sets of RTs associated with that zone - the inclusion set is for
   allowing to accept PIM or IGMP Join for some content (or to be more
   precise for the (S, G) flow that carries that content), and the
   exclusion set is for disallowing to accept PIM or IGMP Joins for some
   other content.  All those RTs (of all subscribers ports) control
   import of BGP Flow Spec routes by the ER.

   Note that the RTs associated with the subscriber port are ordered.
   This permits configurations that accommodate include or exclude
   policies of zones of differing geographic size or overlap.  See below
   for an example.

   If the RTs carried by a given BGP Flow Spec route carrying multicast
   distribution control signaling match the inclusion set of RTs
   associated with a given port on an ER, then PIM or IGMP Joins for the
   (S, G) carried in the route and received from the subscriber(s)



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   connected to that port SHOULD be accepted by the ER.  If the RTs
   carried by the route match the exclusion set, then PIM or IGMP Joins
   for the (S, G) carried in the route MUST NOT be accepted when
   received from the subscriber(s) connected to that port.  (See example
   section below.)

   Each subscriber port on an ER is provisioned with the default
   inclusion/exclusion policy that controls acceptance (or rejection) of
   PIM or IGMP Join messages in the absence of any multicast
   distribution control signaling.  In the former case, in the absence
   of any multicast distribution signaling, subscribers connected to
   that port may receive any multicast flow.  In the latter case, in the
   absence of any multicast distribution control signaling, subscribers
   connected to that port may receive no multicast flows.  BGP Flow Spec
   routes that carry multicast distribution control signaling modify
   such default behavior.

   Once a Content Distribution Controller determines that a particular
   (S, G) multicast stream no longer used to carry a particular content,
   the Content Distribution Controller withdraws the BGP Flow Spec route
   that carries multicast distribution control information for that
   content.

   Note that while [RFC5575] uses the information carried in BGP Flow
   Spec routes for the purpose of Data Plane filtering, this document
   uses this information for the purpose of filtering multicast Control
   Plane traffic (PIM or IGMP).

   To constrain the distribution of BGP Flow Spec routes that carry
   multicast distribution control information to only the relevant ERs,
   the ERs MAY originate Route Target Constraint (RTC) routes that carry
   the RTs that control import of the BGP Flow Spec routes on these ERs.

   To constrain the import of these RTC routes to only the Content
   Distribution Controllers, the Content Distribution Controllers are
   configured with one or more RTs.  These RTs control import by the
   Content Distribution Controller(s) of the RTC routes originated by
   the ERs.  Furthermore, the Content Distribution Controllers MAY
   themselves originate RTC routes that carry the import RT(s)
   configured on these Content Distribution Controllers, and that
   control import of RTC routes by these Content Distribution
   Controllers.

   This document assumes that if a given content provider has multiple
   Content Distribution Controllers, then all of these Controllers are
   provisioned with the same RT(s) that control import of the RTC routes
   originated by the ERs.  Furthermore, this document assumes that if a
   given ISP is providing (multicast) connectivity service to more than



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   one content provider, then the RTC routes originated by any of the
   ERs of that ISP MUST carry the set union of the import RTs used by
   the Content Distribution Controllers of all of these content
   providers.

   RTs carried by routes with AFI 1 and MCAST-FLOWSPEC SAFI SHOULD NOT
   be re-used by routes with any other AFI and/or SAFI.  Likewise, RTs
   carried by routes wiht AFI 2 and MCAST-FLOWSPEC SAFI SHOULD NOT be
   re-used by routes with any other AFI and/or SAFI.  Furthermore, RTs
   carried by routes with AFI 1 and SAFI 132 (AFI/SAFI used by RTC
   routes) SHOULD NOT be re-used by routes with any other AFI and/or
   SAFI.

   Note that while [RFC4684] uses RTC routes to constrain distribution
   of VPN-IP routes [RFC4364], this document uses RTC routes to
   constrain distribution of BGP Flow Spec routes, and also to
   (recursively) constrain distribution of RTC routes themselves.

2.2.  An example of configuration on ERs

   Consider an ER in Manhattan that has a port that is provisioned with
   the following import RTs:

         <include-manhattan, exclude-manhattan, include-nyc, exclude-
         nyc, include-east, exclude-east, include-usa, exclude-usa>

   When the ER receives a Flow Spec route with <exclude-nyc, include-
   manhattan, include-usa> RTs, the ER first try to match "include-
   manhattan" or "exclude-manhattan" (the first ones on the list) - and
   the result is "include-manhattan".  Therefore, the (S, G) carried in
   the Flow Spec route is allowed on that port of the ER.

   Consider another ER in Boston that has a port that is provisioned
   with the following import RTs:

         <include-cambridge, exclude-cambridge, include-bos, exclude-
         bos, include-east, exclude-east, include-usa, exclude-usa>

   The above mentioned Flow Spec route will be imported (due to the
   include-usa RT), and will result in the (S, G) carried in the flow
   Spec route to be allowed on that port of the ER.

   Now consider a different Flow Spec route with the <exclude-usa,
   include-bos, include-nyc, exclude-manhattan> RTs.  The (S, G) carried
   in the route will be disallowed in Manhattan, allowed in Boston, and
   allowed in Queens (as the route will match the "include-nyc" RT).





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3.  Summary of Updates to BGP Flowspec

   As described above, this document makes small changes to the BGP Flow
   Specifcation mechanism when carried using the MCAST-FLOWSPEC SAFI:

   o  Destination addresses will contain a multicast group rather than a
      unicast destination.

   o  Flow specification routes for this SAFI are used for filtering
      multicast Control Plane traffic rather than the matching multicast
      traffic itself.

   o  Flow specification routes for this SAFI will carry one or more
      Route Target extended communities.

   o  Flow specification component types not applicable to signaling
      multicast Control Plane traffic MUST be ignored.  E.g.: ICMP type,
      ICMP code, TCP flags, Fragment.


4.  IANA Considerations

   This document defines a new BGP Subsequent Address Family Identifier
   (SAFI) value, MCAST-FLOWSPEC.  The authors request assignment of a
   value from the First Come, First Served portion of this registry.


5.  Security Considerations

   TBD


6.  Acknowledgements

   The authors would like to thank Han Nguyen for his contributions to
   this document.


7.  References

7.1.  Normative References

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

   [RFC4360]  Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
              Communities Attribute", RFC 4360, February 2006.




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   [RFC4684]  Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk,
              R., Patel, K., and J. Guichard, "Constrained Route
              Distribution for Border Gateway Protocol/MultiProtocol
              Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual
              Private Networks (VPNs)", RFC 4684, November 2006.

   [RFC4760]  Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
              "Multiprotocol Extensions for BGP-4", RFC 4760,
              January 2007.

   [RFC5575]  Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
              and D. McPherson, "Dissemination of Flow Specification
              Rules", RFC 5575, August 2009.

7.2.  Informative References

   [RFC4364]  Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
              Networks (VPNs)", RFC 4364, February 2006.

   [geo-dist]
              Jeng, H., Haas, J., Rekhter, Y., and J. Zhang, "Multicast
              Geo Distribution Control",
              draft-rekhter-geo-distribution-control-03.txt (work in
              progress), 2014.


Authors' Addresses

   Huajin Jeng
   AT&T

   Email: hj2387@att.com


   Jeffrey Haas
   Juniper Networks
   1194 N. Mathida Ave.
   Sunnyvale, CA  94089
   US

   Email: jhaas@juniper.net










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   Yakov Rekhter
   Juniper Networks
   1194 N. Mathida Ave.
   Sunnyvale, CA  94089
   US

   Email: yakov@juniper.net


   Jeffrey (Zhaohui) Zhang
   Juniper Networks
   1194 N. Mathida Ave.
   Sunnyvale, CA  94089
   US

   Email: zzhang@juniper.net



































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