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Versions: (draft-schmidt-multimob-pmipv6-source) 00 01 02 03 04 05 06 07 08 09 RFC 7287

MULTIMOB Group                                         T C. Schmidt, Ed.
Internet-Draft                                               HAW Hamburg
Intended status: Standards Track                                  S. Gao
Expires: July 12, 2012                                          H. Zhang
                                             Beijing Jiaotong University
                                                            M. Waehlisch
                                                    link-lab & FU Berlin
                                                         January 9, 2012


 Mobile Multicast Sender Support in Proxy Mobile IPv6 (PMIPv6) Domains
                  draft-ietf-multimob-pmipv6-source-00

Abstract

   Multicast communication can be enabled in Proxy Mobile IPv6 domains
   via the Local Mobility Anchors by deploying MLD Proxy functions at
   Mobile Access Gateways, via a direct traffic distribution within an
   ISP's access network, or by selective route optimization schemes.
   This document describes the support of mobile multicast senders in
   Proxy Mobile IPv6 domains for all three scenarios.  Mobile sources
   always remain agnostic of multicast mobility operations.

Requirements Language

   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].

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 July 12, 2012.

Copyright Notice




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   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
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Base Solution for Source Mobility and PMIPv6 Routing . . . . .  4
     3.1.  Overview . . . . . . . . . . . . . . . . . . . . . . . . .  4
     3.2.  Base Solution for Source Mobility: Details . . . . . . . .  8
       3.2.1.  Operations of the Mobile Node  . . . . . . . . . . . .  8
       3.2.2.  Operations of the Mobile Access Gateway  . . . . . . .  8
       3.2.3.  Operations of the Local Mobility Anchor  . . . . . . .  8
       3.2.4.  IPv4 Support . . . . . . . . . . . . . . . . . . . . .  9
       3.2.5.  Efficiency of the Distribution System  . . . . . . . . 10
   4.  Direct Multicast Routing . . . . . . . . . . . . . . . . . . . 10
     4.1.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . 10
     4.2.  MLD Proxies at MAGs  . . . . . . . . . . . . . . . . . . . 11
       4.2.1.  PIM-SM Considerations  . . . . . . . . . . . . . . . . 12
       4.2.2.  SSM Considerations . . . . . . . . . . . . . . . . . . 12
     4.3.  PIM-SM . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     4.4.  BIDIR PIM  . . . . . . . . . . . . . . . . . . . . . . . . 13
   5.  Extended Source Mobility Schemes in PMIPv6 . . . . . . . . . . 13
     5.1.  Multiple Upstream Interface Proxy  . . . . . . . . . . . . 13
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 14
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 15
   Appendix A.  Evaluation of Traffic Flows . . . . . . . . . . . . . 16
   Appendix B.  Change Log  . . . . . . . . . . . . . . . . . . . . . 16
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16







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1.  Introduction

   Proxy Mobile IPv6 (PMIPv6) [RFC5213] extends Mobile IPv6 (MIPv6)
   [RFC6275] by network-based management functions that enable IP
   mobility for a host without requiring its participation in any
   mobility-related signaling.  Additional network entities called the
   Local Mobility Anchor (LMA), and Mobile Access Gateways (MAGs), are
   responsible for managing IP mobility on behalf of the mobile node
   (MN).  An MN connected to a PMIPv6 domain, which only operates
   according to the base specifications of [RFC5213], cannot participate
   in multicast communication, as MAGs will discard group packets.

   Multicast support for mobile listeners can be enabled within a PMIPv6
   domain by deploying MLD Proxy functions at Mobile Access Gateways,
   and multicast routing functions at Local Mobility Anchors [RFC6224].
   This base deployment option is the simplest way to PMIPv6 multicast
   extensions in the sense that it follows the common PMIPv6 traffic
   model and neither requires new protocol operations nor additional
   infrastructure entities.  Standard software functions need to be
   activated on PMIPv6 entities, only, at the price of possibly non-
   optimal multicast routing.

   Alternate solutions leverage performance optimization by providing
   multicast routing at the access gateways directly, or by selective
   route optimization schemes.  Such approaches (partially) follow the
   business model of providing multicast data services in parallel to
   PMIPv6 unicast routing.

   Multicast listener support satisfies the needs of receptive use cases
   such as IPTV or sever-centric gaming on mobiles.  However, current
   trends in the Internet enfold towards user-centric, highly
   interactive group applications like user generated streaming,
   conferencing, collective mobile sensing, etc.  Many of these popular
   applications create group content at end systems and can largely
   profit from a direct data transmission to a multicast-enabled
   network.

   This document describes the support of mobile multicast senders in
   Proxy Mobile IPv6 domains subsequently for the base deployment
   scenario [RFC6224], for direct traffic distribution within an ISP's
   access network, as well as for selective route optimization schemes.
   The contribution of this work reflects the source mobility problem as
   discussed in [RFC5757].  Mobile Nodes in this setting remain agnostic
   of multicast mobility operations.







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2.  Terminology

   This document uses the terminology as defined for the mobility
   protocols [RFC6275], [RFC5213] and [RFC5844], as well as the
   multicast edge related protocols [RFC3376], [RFC3810] and [RFC4605].


3.  Base Solution for Source Mobility and PMIPv6 Routing

3.1.  Overview

   The reference scenario for multicast deployment in Proxy Mobile IPv6
   domains is illustrated in Figure 1.  MAGs play the role of first-hop
   access routers that serve multiple MNs on the downstream while
   running an MLD/IGMP proxy instance for every LMA upstream tunnel.




































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                       +-------------+
                       | Multicast   |
                       | Listeners   |
                       +-------------+
                              |
                     ***  ***  ***  ***
                    *   **   **   **   *
                   *                    *
                    *  Fixed Internet  *
                   *                    *
                    *   **   **   **   *
                     ***  ***  ***  ***
                      /            \
                  +----+         +----+
                  |LMA1|         |LMA2|                 Multicast Anchor
                  +----+         +----+
             LMAA1  |              |  LMAA2
                    |              |
                    \\           //\\
                     \\         //  \\
                      \\       //    \\                 Unicast Tunnel
                       \\     //      \\
                        \\   //        \\
                         \\ //          \\
               Proxy-CoA1 ||            ||  Proxy-CoA2
                       +----+          +----+
                       |MAG1|          |MAG2|           MLD Proxy
                       +----+          +----+
                        |  |             |
                MN-HNP1 |  | MN-HNP2     | MN-HNP3
                        |  |             |
                       MN1 MN2          MN3

                 Multicast Sender + Listener(s)

   Figure 1: Reference Network for  Multicast Deployment in PMIPv6 with
                              Source Mobility

   An MN in a PMIPv6 domain will decide on multicast data transmission
   completely independent of its current mobility conditions.  It will
   send packets as initiated by applications, using its source address
   with Home Network Prefix (HNP) and a multicast destination address
   chosen by application needs.  Multicast packets will arrive at the
   currently active MAG via one of its downstream local (wireless)
   links.  A multicast unaware MAG would simply discard these packets in
   the absence of a multicast routing information base (MRIB).

   An MN can successfully distribute multicast data in PMIPv6, if MLD



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   proxy functions are deployed at the MAG as described in [RFC6224].
   In this set-up, the MLD proxy instance serving a mobile multicast
   source has configured its upstream interface at the tunnel towards
   MN's corresponding LMA.  For each LMA, there will be a separate
   instance of an MLD proxy.

   According to the specifications given in [RFC4605], multicast data
   arriving from a downstream interface of an MLD proxy will be
   forwarded to the upstream interface and to all but the incoming
   downstream interfaces that have appropriate forwarding states for
   this group.  Thus multicast streams originating from an MN will
   arrive at the corresponding LMA and directly at all mobile receivers
   co-located at the same MAG and MLD Proxy instance.  Serving as the
   designated multicast router or an additional MLD proxy, the LMA
   forwards data to the fixed Internet, whenever forwarding states are
   maintained by multicast routing.  If the LMA is acting as another MLD
   proxy, it will forward the multicast data to its upstream interface,
   and to downstream interfaces with matching subscriptions,
   accordingly.

   In case of a handover, the MN (unaware of IP mobility) can continue
   to send multicast packets as soon as network connectivity is
   reconfigured.  At this time, the MAG has determined the corresponding
   LMA, and IPv6 unicast address configuration (including PMIPv6
   bindings) has been performed .  Still multicast packets arriving at
   the MAG are discarded (if not buffered) until the MAG has completed
   the following steps.

   1.  The MAG has determined that the MN is admissible to multicast
       services.

   2.  The MAG has added the new downstream link to the MLD proxy
       instance with up-link to the corresponding LMA.

   As soon as the MN's uplink is associated with the corresponding MLD
   proxy instance, multicast packets are forwarded again to the LMA and
   eventually to receivers within the PMIP domain (see the call flow in
   Figure 2).  In this way, multicast source mobility is transparently
   enabled in PMIPv6 domains that deploy the base scenario for
   multicast.











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   MN1             MAG1             MN2             MAG2             LMA
   |                |                |               |                |
   |                | Mcast Data     |               |                |
   |                |<---------------+               |                |
   |                |     Mcast Data |               |                |
   |  Join(G)       +================================================>|
   +--------------> |                |               |                |
   | Mcast Data     |                |               |                |
   |<---------------+                |               |                |
   |                |                |               |                |
   |           <  Movement of MN 2 to MAG2  &  PMIP Binding Update  > |
   |                |                |               |                |
   |                |                |--- Rtr Sol -->|                |
   |                |                |<-- Rtr Adv ---|                |
   |                |                |               |                |
   |                |                |   < MLD Proxy Configuration >  |
   |                |                |               |                |
   |                |                |   MLD Query   |                |
   |                |                |<--------------+                |
   |                |                |  Mcast Data   |                |
   |                |                +-------------->|                |
   |                |                |               | Mcast Data     |
   |                |                |               +===============>|
   |                |                |               |                |
   |                |   Mcast Data   |               |                |
   |                |<================================================+
   |  Mcast Data    |                |               |                |
   |<---------------+                |               |                |
   |                |                |               |                |

   Figure 2: Call Flow for Group Communication in Multicast-enabled PMIP

   These multicast deployment considerations likewise apply for mobile
   nodes that operate with their IPv4 stack enabled in a PMIPv6 domain.
   PMIPv6 can provide IPv4 home address mobility support [RFC5844].
   IPv4 multicast is handled by an IGMP proxy function at the MAG in an
   analogous way.

   Following these deployment steps, multicast traffic distribution
   transparently inter-operates with PMIPv6.  It is worth noting that an
   MN - while being attached to the same MAG as the mobile source, but
   associated with a different LMA - cannot receive multicast traffic on
   a shortest path.  Instead, multicast streams flow up to the LMA of
   the mobile source, are transferred to the LMA of the mobile listener
   and tunneled downwards to the MAG again (see Appendix A for further
   considerations).





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3.2.  Base Solution for Source Mobility: Details

   Incorporating multicast source mobility in PMIPv6 requires to deploy
   general multicast functions at PMIPv6 routers and to define their
   interaction with the PMIPv6 protocol in the following way.

3.2.1.  Operations of the Mobile Node

   A Mobile Node willing to send multicast data will proceed as if
   attached to the fixed Internet.  No specific mobility or other
   multicast related functionalities are required at the MN.

3.2.2.  Operations of the Mobile Access Gateway

   A Mobile Access Gateway is required to have MLD proxy instances
   deployed, one for each tunnel to an LMA, which serves as its unique
   upstream link (cf., [RFC6224]).  On the arrival of an MN, the MAG
   decides on the mapping of downstream links to a proxy instance and
   the upstream link to the LMA based on the regular Binding Update List
   as maintained by PMIPv6 standard operations.  When multicast data is
   received from the MN, the MAG MUST identify the corresponding proxy
   instance from the incoming interface and forwards multicast data
   upstream according to [RFC4605].

   The MAG MAY apply special admission control to enable multicast data
   transition from an MN.  It is advisable to take special care that MLD
   proxy implementations do not redistribute multicast data to
   downstream interfaces without appropriate subscriptions in place.

3.2.3.  Operations of the Local Mobility Anchor

   For any MN, the Local Mobility Anchor acts as the persistent Home
   Agent and at the same time as the default multicast upstream for the
   corresponding MAG.  It will manage and maintain a multicast
   forwarding information base for all group traffic arriving from its
   mobile sources.  It SHOULD participate in multicast routing functions
   that enable traffic redistribution to all adjacent LMAs within the
   PMIPv6 domain and thereby ensure a continuous receptivity while the
   source is in motion.

3.2.3.1.  Local Mobility Anchors Operating PIM

   Local Mobility Anchors that operate the PIM-SM routing protocol
   [RFC4601] will require sources to be directly connected for sending
   PIM registers to the RP.  This does not hold in a PMIPv6 domain, as
   MAGs are routers intermediate to MN and the LMA.  In this sense, MNs
   are multicast sources external to the PIM-SM domain.




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   To mitigate this incompatibility common to all subsidiary MLD proxy
   domains, the LMA should act as a PIM Border Router and activate the
   Border-bit.  In this case, the DirectlyConnected(S) is treated as
   being TRUE for mobile sources and the PIM-SM forwarding rule "iif ==
   RPF_interface(S)" is relaxed to be TRUE, as the incoming tunnel
   interface from MAG to LMA is considered as not part of the PIM-SM
   component of the LMA (see A.1 of [RFC4601] ).

   Notably, running BIDIR PIM [RFC5015] on LMAs remains robust with
   respect to source location and does not require a special
   configuration.

3.2.4.  IPv4 Support

   An MN in a PMIPv6 domain may use an IPv4 address transparently for
   communication as specified in [RFC5844].  For this purpose, an LMA
   can register an IPv4-Proxy-CoA in its Binding Cache and the MAG can
   provide IPv4 support in its access network.  Correspondingly,
   multicast membership management will be performed by the MN using
   IGMP.  For multicast support on the network side, an IGMP proxy
   function needs to be deployed at MAGs in exactly the same way as for
   IPv6.  [RFC4605] defines IGMP proxy behaviour in full agreement with
   IPv6/MLD.  Thus IPv4 support can be transparently provided following
   the obvious deployment analogy.

   For a dual-stack IPv4/IPv6 access network, the MAG proxy instances
   SHOULD choose multicast signaling according to address configurations
   on the link, but MAY submit IGMP and MLD queries in parallel, if
   needed.  It should further be noted that the infrastructure cannot
   identify two data streams as identical when distributed via an IPv4
   and IPv6 multicast group.  Thus duplicate data may be forwarded on a
   heterogeneous network layer.

   A particular note is worth giving the scenario of [RFC5845] in which
   overlapping private address spaces of different operators can be
   hosted in a PMIP domain by using GRE encapsulation with key
   identification.  This scenario implies that unicast communication in
   the MAG-LMA tunnel can be individually identified per MN by the GRE
   keys.  This scenario still does not impose any special treatment of
   multicast communication for the following reasons.

   Multicast streams from and to MNs arrive at a MAG on point-to-point
   links (identical to unicast).  Multicast data transmission from the
   MAG to the corresponding LMA is link-local between the routers and
   routing/forwarding remains independent of any individual MN.  So the
   MAG-proxy and the LMA SHOULD NOT use GRE key identifiers, but plain
   GRE encapsulation in multicast communication (including MLD queries
   and reports).  Multicast traffic sent upstream and downstream of MAG-



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   to-LMA tunnels proceeds as router-to-router forwarding according to
   the multicast routing information base (MRIB) of the MAG or LMA and
   independent of MN's unicast addresses, while the MAG proxy instance
   re-distributes multicast data down the point-to-point links
   (interfaces) according to its own MRIB, independent of MN's IP
   addresses.

3.2.5.  Efficiency of the Distribution System

   In the following efficiency-related issues are enumerated.

   Multicast reception at LMA  In the current deployment scenario, the
      LMA will receive all multicast traffic originating from its
      associated MNs.  There is no mechanism to suppress upstream
      forwarding in the absence of receivers.

   MNs on the same MAG using different LMAs  For a mobile receiver and a
      source that use different LMAs, the traffic has to go up to one
      LMA, cross over to the other LMA, and then be tunneled back to the
      same MAG, causing redundant flows in the access network and at the
      MAG.


4.  Direct Multicast Routing

   There are deployment scenarios, where multicast services are
   available throughout the access network independent of the PMIPv6
   routing system [I-D.zuniga-multimob-pmipv6-ropt].  In these cases,
   the visited networks grant a local content distribution service (in
   contrast to LMA-based home subscription) with locally optimized
   traffic flows.  It is also possible to deploy a mixed service model
   of local and LMA-based subscriptions, provided a unique way of
   service selection is implemented.  For example, access routers (MAGs)
   could decide on service access based on the multicast address G or
   the SSM channel (S,G) under request (see Section 5 for a further
   discussion).

4.1.  Overview

   Direct multicast access can be supported by

   o  native multicast routing provided by one multicast router that is
      neighboring MLD proxies deployed at MAGs within a flat access
      network, or via tunnel uplinks,

   o  a multicast routing protocol such as PIM-SM [RFC4601] or BIDIR-PIM
      [RFC5015] deployed at the MAGs.




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               ***  ***  ***  ***
              *   **   **   **   *
             *                    *
             *      Multicast     *
    +----+   *   Infrastructure   *                               +----+
    |LMA |    *   **   **   **   *                                |LMA |
    +----+     ***  ***  ***  ***                                 +----+
         |          //  \\                                             |
         \\        //    \\       PMIP (unicast)                       |
  PMIP    \\      //      \\      //          \\   **  ***  *** **    //
(unicast)  \\    //        \\    //            \\ *   **   **     ** //
            \\  //          \\  //              \\*    Multicast   *//
            || ||           || ||              * ||     Routing    || *
           +----+          +----+              * +----+         +----+ *
 MLD Proxy |MAG1|          |MAG2|              * |MAG1|         |MAG2| *
           +----+          +----+               *+----+ **   ** +----+*
            |  |             |                    |  |***  ***   ***|
            |  |             |                    |  |              |
           MN1 MN2          MN3                 MN1 MN2            MN3

 (a) Multicast Access at Proxy Uplink      (b) Multicast Routing at MAG

   Figure 3: Reference Networks for (a) Proxy-assisted Direct Multicast
             Access and (b) Dynamic Multicast Routing at MAGs

   Figure 3 displays the corresponding deployment scenarios, which
   separate multicast from PMIPv6 unicast routing.  It is assumed
   throughout these scenarios that all MAGs (MLD proxies) are linked to
   a single multicast routing domain.

   Multicast traffic distribution can be simplified in these scenarios.
   A single proxy instance at MAGs with up-link into the multicast
   domain will serve as a first hop multicast gateway and avoid traffic
   duplication or detour routing.  Multicast routing functions at MAGs
   will seamlessly embed access gateways within a multicast cloud.
   However, mobility of the multicast source in this scenario will
   require some multicast routing protocols to rebuild distribution
   trees.  This can cause significant service disruptions or delays (see
   [RFC5757] for further aspects).  Deployment details are specific to
   the multicast routing protocol in use, in the following described for
   common protocols.

4.2.  MLD Proxies at MAGs

   In a PMIPv6 domain, single MLD proxy instances can be deployed at
   each MAG to enable multicast service at the access (see Figure 3 (a)
   ).  To avoid service disruptions on handovers, the uplinks of all
   proxies SHOULD be adjacent to the same next-hop multicast router.



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   This can either be achieved by arranging proxies within a flat access
   network, or by upstream tunnels that terminate at a common multicast
   router.

   Multicast data submitted by a mobile source will reach the MLD proxy
   at the MAG that subsequently forwards flows to the upstream and all
   downstream interfaces with appropriate subscriptions.  Traversing the
   upstream will lead traffic into the multicast infrastructure (e.g.,
   to a PIM Designated Router) which will route packets to all local
   MAGs that have joined the group, as well as further upstream
   according to protocol procedures and forwarding states.

   On handover, a mobile source will reattach at a new MAG and can
   continue to send multicast packets as soon as PMIPv6 unicast
   configurations have completed.  Like at the previous MAG, the new MLD
   proxy will forward data upstream and downstream to subscribers.
   Listeners local to the previous MAG will continue to receive group
   traffic via the local multicast distribution infrastructure following
   aggregated listener reports of the previous proxy.  In general, the
   mobile source remains unchanged when seen from the wider multicast
   infrastructure.

4.2.1.  PIM-SM Considerations

   A mobile source that transmits data via an MLD proxy will not be
   directly connected to a PIM Designated Router as discussed in
   Section 3.2.3.1.  Countermeasures apply correspondingly.

   A PIM Designated Router that is connected to MLD proxies via
   individual IP-tunnel interfaces will experience invalid PIM source
   states on handover.  This problem can be mitigated by aggregating
   proxies on a lower layer.

4.2.2.  SSM Considerations

   Source-specific subscriptions invalidate with routes, whenever the
   source moves from or to the MAG/proxy of a subscriber.  Multicast
   forwarding states will rebuild with unicast route changes.  However,
   this may lead to noticeable service disruptions for locally
   subscribed nodes.

4.3.  PIM-SM

   TODO







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4.4.  BIDIR PIM

   TODO


5.  Extended Source Mobility Schemes in PMIPv6

   In this section, specific optimization approaches to multicast source
   mobility are introduced.

5.1.  Multiple Upstream Interface Proxy

   Although multicast communication can be enabled in PMIPv6 domains by
   deploying MLD Proxy functions at MAG, some disadvantages still exist.
   Firstly, for a proxy device performing IGMP/MLD-based forwarding has
   a single upstream interface and one or more downstream interfaces as
   described in RFC4605, there should be many MLD Proxy functions
   deployed at one MAG, which is complicated and then is difficult for
   implementation and management.  And then when the multicast packets
   arrive at the MAG running multiple parallel MLD proxy functions,
   there may be confusions for the data if there is no extra processing
   or filtering scheme at the MAG.  In addition, the route optimization
   issue is still up in the air, that is, for a mobile receiver and a
   source on the same MAG using different LMAs, the traffic has to go up
   to one LMA, cross over to the other LMA, and then be tunneled back to
   the same MAG, causing redundant flows in the access network and at
   the MAG.  Therefore, the MLD Proxy function should be extended to
   accommodate the PMIPv6 protocol.  As same as described in [RFC6224]
   and this document (s. abobe), the MLD proxy functions are deployed at
   the MAG, while only one MLD Proxy function is required to run at the
   MAG and multiple upstream interfaces can be set for the MLD Proxy
   instance, which is called Multi-Upstream Interfaces MLD Proxy
   (MUIMP).

   ....  TODO details.


6.  IANA Considerations

   TODO.

   Note to RFC Editor: this section may be removed on publication as an
   RFC.


7.  Security Considerations

   TODO



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   Consequently, no new threats are introduced by this document in
   addition to those identified as security concerns of [RFC3810],
   [RFC4605], [RFC5213], and [RFC5844].

   However, particular attention should be paid to implications of
   combining multicast and mobility management at network entities.  As
   this specification allows mobile nodes to initiate the creation of
   multicast forwarding states at MAGs and LMAs while changing
   attachments, threats of resource exhaustion at PMIP routers and
   access networks arrive from rapid state changes, as well as from high
   volume data streams routed into access networks of limited
   capacities.  In addition to proper authorization checks of MNs, rate
   controls at replicators MAY be required to protect the agents and the
   downstream networks.  In particular, MLD proxy implementations at
   MAGs SHOULD carefully procure for automatic multicast state
   extinction on the departure of MNs, as mobile multicast listeners in
   the PMIPv6 domain will not actively terminate group membership prior
   to departure.


8.  Acknowledgements

   The authors would like to thank (in alphabetical order) Muhamma Omer
   Farooq, Aaron Feng, Dirk von Hugo, Ning Kong, Jouni Korhonen, He-Wu
   Li, Akbar Rahman, Stig Venaas, Li-Li Wang, Qian Wu, Zhi-Wei Yan for
   advice, help and reviews of the document.  Funding by the German
   Federal Ministry of Education and Research within the G-LAB
   Initiative (project HAMcast) is gratefully acknowledged.


9.  References

9.1.  Normative References

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

   [RFC2710]  Deering, S., Fenner, W., and B. Haberman, "Multicast
              Listener Discovery (MLD) for IPv6", RFC 2710,
              October 1999.

   [RFC3376]  Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A.
              Thyagarajan, "Internet Group Management Protocol, Version
              3", RFC 3376, October 2002.

   [RFC3810]  Vida, R. and L. Costa, "Multicast Listener Discovery
              Version 2 (MLDv2) for IPv6", RFC 3810, June 2004.




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   [RFC4601]  Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
              "Protocol Independent Multicast - Sparse Mode (PIM-SM):
              Protocol Specification (Revised)", RFC 4601, August 2006.

   [RFC4605]  Fenner, B., He, H., Haberman, B., and H. Sandick,
              "Internet Group Management Protocol (IGMP) / Multicast
              Listener Discovery (MLD)-Based Multicast Forwarding
              ("IGMP/MLD Proxying")", RFC 4605, August 2006.

   [RFC5015]  Handley, M., Kouvelas, I., Speakman, T., and L. Vicisano,
              "Bidirectional Protocol Independent Multicast (BIDIR-
              PIM)", RFC 5015, October 2007.

   [RFC5213]  Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
              and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.

   [RFC5844]  Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
              Mobile IPv6", RFC 5844, May 2010.

   [RFC6275]  Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
              in IPv6", RFC 6275, July 2011.

9.2.  Informative References

   [I-D.zuniga-multimob-pmipv6-ropt]
              Zuniga, J., Contreras, L., Bernardos, C., Jeon, S., and Y.
              Kim, "Multicast Mobility Routing Optimizations for Proxy
              Mobile IPv6", draft-zuniga-multimob-pmipv6-ropt-01 (work
              in progress), October 2011.

   [RFC2236]  Fenner, W., "Internet Group Management Protocol, Version
              2", RFC 2236, November 1997.

   [RFC5757]  Schmidt, T., Waehlisch, M., and G. Fairhurst, "Multicast
              Mobility in Mobile IP Version 6 (MIPv6): Problem Statement
              and Brief Survey", RFC 5757, February 2010.

   [RFC5845]  Muhanna, A., Khalil, M., Gundavelli, S., and K. Leung,
              "Generic Routing Encapsulation (GRE) Key Option for Proxy
              Mobile IPv6", RFC 5845, June 2010.

   [RFC6224]  Schmidt, T., Waehlisch, M., and S. Krishnan, "Base
              Deployment for Multicast Listener Support in Proxy Mobile
              IPv6 (PMIPv6) Domains", RFC 6224, April 2011.







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Appendix A.  Evaluation of Traffic Flows

   TODO


Appendix B.  Change Log

   The following changes have been made from version
   draft-ietf-multimob-pmipv6-source-00:


Authors' Addresses

   Thomas C. Schmidt
   HAW Hamburg
   Berliner Tor 7
   Hamburg  20099
   Germany

   Email: schmidt@informatik.haw-hamburg.de
   URI:   http://inet.cpt.haw-hamburg.de/members/schmidt


   Shuai Gao
   Beijing Jiaotong University
   Beijing,
   China

   Phone:
   Fax:
   Email: shgao@bjtu.edu.cn
   URI:


   Hong-Ke Zhang
   Beijing Jiaotong University
   Beijing,
   China

   Phone:
   Fax:
   Email: hkzhang@bjtu.edu.cn
   URI:








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   Matthias Waehlisch
   link-lab & FU Berlin
   Hoenower Str. 35
   Berlin  10318
   Germany

   Email: mw@link-lab.net












































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