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Versions: 00

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


             Multicast Distribution Reachability Signaling
                         draft-ietf-idr-mdrs-00

Abstract

   This document describes a mechanism whereby a subscriber's Internet
   service provider may signal in BGP the ability of the subscriber
   network to receive content using multicast connectivity.  This
   mechanism is called Multicast Distribution Reachability Signaling
   (MDRS).

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   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
   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



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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.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Specification of Requirements . . . . . . . . . . . . . . . . . 3
     2.1.  Multicast Distribution Reachability Signaling . . . . . . . 4
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 5
   6.  Normative References  . . . . . . . . . . . . . . . . . . . . . 5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 5




































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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.  This content
   provider can deliver its content via unicast connectivity or, if
   supported by the subscriber network, multicast connectivity.  A
   mechanism is required to determine if the subscriber network supports
   delivery of content to subscribers via multicast connectivity.

   This document describes a mechanism whereby the subscriber's Internet
   service provider may signal in BGP the ability of the subscriber
   network to receive the content using multicast connectivity.  This
   mechanism is called Multicast Distribution Reachability Signaling
   (MDRS).

   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 can offer both multicast and unicast connectivity service
   to the subscribers of the content provider.  Content providers use
   these ISPs to deliver content to their subscribers.

   Subscribers are connected to the Egress 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.

   In the case where a particular subscriber of a given content provider
   does not have multicast connectivity to its ER, the content provider
   would use IP unicast service provided by the ISP to transmit the
   particular content to that subscriber.


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].




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2.1.  Multicast Distribution Reachability Signaling

   Multicast distribution reachability signaling is responsible for
   giving a content provider, and specifically Content Distribution
   Controller(s) of the content provider the information of whether a
   particular subscriber of that content provider has multicast
   connectivity to an ER of an ISP that the content provider uses for
   distributing its content.

   This document assumes that each ER can determine the multicast
   reachability status for each of the subscriber connected to that ER.
   Procedures by which an ER accomplishes this are outside the scope of
   this document.

   To indicate whether a given ER has multicast reachability to a
   subscriber (be that either a native multicast or AMT) this document
   uses BGP as follows.  An ER originates into IBGP routes for the
   subscribers connected to that ER for which the ER has multicast
   reachability.  These routes are carried using BGP multi-protocol
   capabilities [RFC4760] with AFI 1 or 2, and the MCAST-REACH SAFI.
   The NLRI field in the MP_REACH_NLRI/MP_UNREACH_NLRI attribute of
   these routes contains subscribers' IP addresses encoded as IP address
   prefixes.  The value of the AFI field in the MP_REACH_NLRI/
   MP_UNREACH_NLRI attribute of these routes determines whether
   subscribers' addresses are IPv4 or IPv6 (AFI 1 indicates IPv4
   addresses, AFI 2 indicates IPv6 addresses).

   A Content Distribution Controller, when it receives such routes, uses
   them to determine whether the content could be delivered to the
   subscribers via the ISP who owns the ERs using the multicast
   connectivity service provided by the ISP.

   To constrain the flow of BGP routes that carry multicast distribution
   reachability information such routes carry a particular Route Target
   (RT) Extended Community [RFC4360], and Content Distribution
   Controller(s) are provisioned to import routes with such a RT.

   RTs carried by routes with AFI 1 and MCAST-REACH SAFI SHOULD NOT be
   re-used by routes with any other AFI and/or SAFI.  Likewise, RTs
   carried by routes with AFI 2 and MCAST-REACH SAFI SHOULD NOT be re-
   used by routes with any other AFI and/or SAFI.

   To facilitate such constrained distribution of multicast distribution
   reachability information one MAY use Constrained Route Distribution
   [RFC4684].






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3.  IANA Considerations

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


4.  Security Considerations

   TBD


5.  Acknowledgements

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


6.  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.

   [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.


Authors' Addresses

   Huajin Jeng
   AT&T


   Phone:
   Email: hj2387@att.com






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

   Email: jhaas@juniper.net


   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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