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MULTIMOB Group                                                 H. Asaeda
Internet-Draft                                                      NICT
Intended status: Standards Track                                P. Seite
Expires: April 25, 2013                                   France Telecom
                                                        October 22, 2012


          Multicast Routing Optimization by PIM-SM with PMIPv6
                draft-asaeda-multimob-pmip6-extension-11

Abstract

   This document describes IP multicast routing optimization using
   PIM-SM in Proxy Mobile IPv6 (PMIPv6) environment.  The Mobile Access
   Gateway (MAG) and the Local Mobility Anchor (LMA) are the mobility
   entities defined in the PMIPv6 protocol and act as PIM-SM routers.
   The proposed protocol optimization addresses the tunnel convergence
   problem and cooperates with seamless handover mechanisms.

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 April 25, 2013.

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



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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.  Conventions and Terminology  . . . . . . . . . . . . . . . . .  4
   3.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  4
     3.1.  Multicast Communication in PMIPv6  . . . . . . . . . . . .  4
     3.2.  Protocol Sequence for Multicast Channel Subscription . . .  6
   4.  Multicast Tunnel (M-Tunnel)  . . . . . . . . . . . . . . . . .  7
     4.1.  Packet Encapsulation . . . . . . . . . . . . . . . . . . .  7
     4.2.  M-Tunnels Connecting to Multiple PIM-SM Routers and
           ECMP Routing . . . . . . . . . . . . . . . . . . . . . . .  9
   5.  Local Mobility Anchor Operation  . . . . . . . . . . . . . . . 10
   6.  Mobile Access Gateway Operation  . . . . . . . . . . . . . . . 11
   7.  Mobile Node Operation  . . . . . . . . . . . . . . . . . . . . 11
   8.  Localized Multicast Routing  . . . . . . . . . . . . . . . . . 12
   9.  Smooth Handover  . . . . . . . . . . . . . . . . . . . . . . . 12
   10. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 15
   11. Security Considerations  . . . . . . . . . . . . . . . . . . . 15
   12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 15
   13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
     13.1. Normative References . . . . . . . . . . . . . . . . . . . 15
     13.2. Informative References . . . . . . . . . . . . . . . . . . 16
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
























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1.  Introduction

   Proxy Mobile IPv6 (PMIPv6) [1] enables network-based mobility for
   IPv6 mobile nodes (MNs) that do not implement any mobility protocols.
   The Local Mobility Anchor (LMA) is the topological anchor point to
   manages the mobile node's binding state.  The Mobile Access Gateway
   (MAG) is an access router or gateway that manages the mobility-
   related signaling for an MN.  An MN is attached to the Proxy Mobile
   IPv6 Domain (PMIPv6-Domain) that includes LMA and MAG(s), and is able
   to receive data coming from outside of the PMIPv6-Domain through LMA
   and MAG.

   Network-based mobility support for unicast is addressed in [1], while
   multicast support in PMIPv6 is not discussed in it.  Since LMA and
   MAG set up a bi-directional IPv6-in-IPv6 tunnel for each mobile node
   and forwards all mobile node's traffic according to [1], it highly
   wastes network resources when a large number of mobile nodes join/
   subscribe the same multicast sessions/channels, because independent
   data copies of the same multicast packet are delivered to the
   subscriber nodes in a unicast manner through MAG.

   The base solution described in [12] provides options for deploying
   multicast listener functions in PMIPv6-Domains without modifying
   mobility and multicast protocol standards.  However, in this
   specification, MAG MUST act as an MLD proxy [2] and hence MUST
   dedicate a tunnel link between LMA and MAG to an upstream interface
   for all multicast traffic.  This limitation does not allow to use
   PIM-SM native routing on MAG, and hence does not solve the tunnel
   convergence problem; MAG receives the same data from multiple LMAs
   when MAG attaches to them for mobile nodes and has subscribed the
   same multicast channel to them.  It does not enable direct routing
   and does not optimize source mobility.

   This document describes IP multicast routing optimization using
   PIM-SM in Proxy Mobile IPv6 (PMIPv6) environment.  The Mobile Access
   Gateway (MAG) and the Local Mobility Anchor (LMA) are the mobility
   entities defined in the PMIPv6 protocol and act as PIM-SM routers.
   The proposed protocol optimization assumes that both LMA and MAG
   enable the Protocol-Independent Multicast - Sparse Mode (PIM-SM)
   multicast routing protocol [3].  The proposed optimization uses a
   dedicated GRE [4] tunnel for multicast, called M-Tunnel between MAG
   and PIM-SM router such as LMA.  The proposed protocol optimization
   addresses the tunnel convergence problem and provides seamless
   handover.  It can cooperate with localized routing and direct routing
   to deliver IP multicast packets for mobile nodes and source mobility.
   In this document, because multicast listener mobility is mainly
   focused on, the detail specification of source mobility is not
   described.



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   This document does not require to change unicast communication
   methods or protocols defined in [1], and therefore both unicast and
   multicast communications for mobile nodes in PMIPv6-Domain are
   enabled if this extension is implemented.


2.  Conventions and Terminology

   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 [5].

   The following terms used in this document are to be interpreted as
   defined in the Proxy Mobile IPv6 specification [1]; Mobile Access
   Gateway (MAG), Local Mobility Anchor (LMA), Mobile Node (MN), Proxy
   Mobile IPv6 Domain (PMIPv6-Domain), LMA Address (LMAA), Proxy Care-of
   Address (Proxy-CoA), Mobile Node's Home Network Prefix (MN-HNP),
   Mobile Node Identifier (MN-Identifier), Proxy Binding Update (PBU),
   and Proxy Binding Acknowledgement (PBA).


3.  Overview

3.1.  Multicast Communication in PMIPv6

   Required components to enable IP multicast are multicast routing
   protocols and host-and-router communication protocols.  This document
   assumes PIM-SM [3] as the multicast routing protocol and Multicast
   Listener Discovery (MLD) as the host-and-router communication
   protocol.  This document allows mobile nodes to participate in Any-
   Source Multicast (ASM) and Source-Specific Multicast (SSM) [6].
   However, in order to explicitly participate in SSM, mobile nodes MUST
   support either MLDv2 [7] or Lightweight-MLDv2 (LW-MLDv2) [8].

   The architecture of a Proxy Mobile IPv6 domain is shown in Figure 1.
   LMA and MAG are the core functional entities in PMIPv6-Domain.  The
   entire PMIPv6-Domain appears as a single link from the perspective of
   each mobile node.













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                       +---------+
                       | Content |
                       | Source  |
                       +---------+
                            |
                 ***  ***  ***  ***  ***
                *   **   **   **   **   *
               *                         *
                *     Fixed Internet    *
               *                         *
                *   **   **   **   **   *
                 ***  ***  ***  ***  ***
                     /            \
                  +----+        +----+
                  |LMA1|        |LMA2|
                  +----+        +----+
           LMAA1 -> |              | <-- LMAA2
                    |              |
                    \\            //\\
                     \\          //  \\
                      \\        //    \\
                       \\      //      \\
                        \\    //        \\
                         \\  //          \\
             Proxy-CoA1--> |              | <-- Proxy-CoA2
                        +----+          +----+
                        |MAG1|---{MN2}  |MAG2|
                        +----+  |       +----+
                          |     |         |
             MN-HNP1 -->  |   MN-HNP2     |  <-- MN-HNP3, MN-HNP4
                        {MN1}           {MN3}

                    Figure 1: Proxy Mobile IPv6 Domain

   When a mobile node wants to subscribe/unsubscribe a multicast
   channel, it sends MLD Report messages specifying sender and multicast
   addresses to the access link.  The attached MAG detects this
   membership information and sends the PIM Join/Prune message to the
   corresponding LMA over a bi-directional GRE tunnel called M-Tunnel
   (described in Section 4) when the LMA is selected as the previous-hop
   router for the multicast channel, or sends the PIM Join/Prune message
   to the adjacent upstream multicast router for the multicast channel.
   When the LMA or the adjacent router receives the PIM Join/Prune
   message, it coordinates the corresponding multicast routing tree if
   necessary and starts forwarding the data.

   When the MAG detects mobile node's handover, it can proceed the
   seamless handover procedures.  Since both PMIPv6 and multicast



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   protocols (i.e., MLD and PIM-SM) do not have functions for multicast
   context transfer in their original protocol specifications, the
   external functions or protocols should be used for handover.  One of
   the possibile ways is the use of "mobile node's Policy Profile", as
   it could include "multicast channel information", which expresses
   mobile node's subscribing multicast channel list, as well as the
   mandatory fields of the Policy Profile specified in [1].  Mobile
   node's Policy Profile is provided by "policy store" whose definition
   is the same as of [1].

3.2.  Protocol Sequence for Multicast Channel Subscription

   A mobile node sends unsolicited MLD Report messages including source
   and multicast addresses when it subscribes a multicast channel.
   Although MLDv2 specification [7] permits to use the unspecified
   address (::) for a host whose interface has not acquired a valid
   link-local address yet, MAG SHOULD send MLDv2 Report messages with a
   valid IPv6 link-local source address as defined in [13].  As well,
   MLDv2 Report messages MAY be sent with an IP destination address of
   FF02:0:0:0:0:0:0:16, to which all MLDv2-capable multicast routers
   listen, but the IP unicast address of the attached MAG SHALL be used
   for the destination of MLDv2 Report messages.

   When the MAG operating as a PIM-SM router receives MLD Report
   messages from attached mobile nodes, it joins the multicast delivery
   tree by sending PIM Join messages to its neighboring routers
   (Figure 2).  When the upstream router for the requested channel is
   LMA, the MAG sends the corresponding PIM Join messages to the LMA
   using M-Tunnel (described in Section 4), if the MAG has not joined to
   the requested multicast channel.  When the upstream router for the
   requested channel is an adjacent router that is not the LMA, the MAG
   sends the corresponding PIM Join messages to the adjacent upstream
   router natively, if the MAG has not joined to the requested multicast
   channel.  The LMA or the adjacent upstream router then joins the
   multicast delivery tree and forwards the packets to the downstream
   MAG.















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   MN1        MN2             MAG                 LMA
    |          |               |                   |
    |------MLD Report--------->|                   |
    |     (S1,G1) join         |  PIM (S1,G1) Join |
    |          |               |===== M-Tunnel ===>|
    |          |               |                   |---> PIM (S1,G1) Join
    |          |               |                   |
    |          |--MLD Report-->|                   |
    |          | (S2,G2) join  |                   |
    |          |               |---> PIM (S2,G2) Join
    |          |               |                   |
    |          |--MLD Report-->|                   |
    |          | (S1,G1) join  |                   |
    |          |               |                   |

            Figure 2: MLD Report and PIM Messages Transmission

   The MAG selects only one upstream interface (either M-Tunnel
   interface or physical interface) for a multicast channel by the
   Reverse Path Forwarding (RPF) algorithm.  This does not cause the
   tunnel convergence problem, because Multicast Routing Information
   Base (MRIB) used by PIM-SM selects only one upstream interface for
   each multicast channel and hence duplicate packets are not forwarded
   to the MAG.


4.  Multicast Tunnel (M-Tunnel)

4.1.  Packet Encapsulation

   M-Tunnel is a bi-directional GRE tunnel [4] dedicated for PIM
   messages and IP multicast data transmissions.  The tunnel end-point
   of M-Tunnel is a MAG that is a PIM-SM capable router.  Another tunnel
   end-point is also a PIM-SM capable router.  The typical use case of
   M-Tunnel is to establish a bi-directional tunnel link between LMA and
   MAG; therefore LMA shall be another tunnel end-point.  M-Tunnel can
   be established in a bootstrap phase of MAG (without detecting a
   multicast channel subscription request from a mobile node) and kept
   while the MAG enables PIM routing functions to forward multicast
   packets.  An M-Tunnel is not set up per mobile node basis, but per
   MAG basis; it can be shared with mobile nodes attached to the MAG as
   seen in Figure 3.









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                   MC1
                      \
                       \-->
                   MC2---->LMA===MC1,MC2 for MNs====>MAG

                   MC: Multicast packets, ==>: M-Tunnel

          Figure 3: Multicast packet forwarding through M-Tunnel

   In order for the PIM routing protocol to use an M-Tunnel for
   multicast forwarding, an M-Tunnel interface must be recognized by the
   PIM routing protocol as the upstream multicast interface for MAG.  It
   is done by the configuration of static multicast routes, such as "ip
   mroute 0.0.0.0 0.0.0.0 gre0" or "ip mroute 1.1.1.0 255.255.255.0
   gre0".  By such configuration, MAG inserts the multicast route paths
   using the M-Tunnel into its MRIB.  MAG then selects the M-Tunnel
   interface as the corresponding RPF interface, and forwards the PIM
   Join/Prune messages over the M-Tunnel.  If operators want to select
   other interface, e.g. a physical interface, as the upstream multicast
   interface for some specific source prefixes, e.g. sources inside the
   PMIPv6-Domain, they can *additionally* configure the specific
   multicast routes with longer prefixes.  This configuration will be
   used for direct routing.  Then the MAG selects as the appropriate
   upstream router according to the MRIB entry.  Note that the case
   having multiple M-Tunnels configured on MAG is described in
   Section 4.2.

   The format of the tunneled multicast packet forwarded from LMA to MAG
   is shown below.  "S" and "G" are the same notation used for (S,G)
   multicast channel.

     IPv6 header (src= LMAA, dst= Proxy-CoA) /* Outer Header */
        GRE header                           /* Encapsulation Header */
           IPv6 header (src= S, dst= G)      /* Inner Header */
              Upper layer protocols          /* Packet Content */

        Figure 4: Multicast packet format tunneled from LMA to MAG

   When a PIM message is sent from MAG to LMA, the src and dst addresses
   of the outer tunnel header will be replaced to Proxy-CoA and LMAA,
   respectively.  To convey a PIM message, the src address of the inner
   packet header is changed to either LMA's or MAG's link-local address.
   The dst address of the packet header is assigned based on the PIM's
   condition (see [3]).

   In order to establish M-Tunnel, LMA and MAG need to negotiate GRE
   encapsulation and GRE keys for M-Tunnel.  The GRE Key option to be
   used for the negotiation of GRE tunnel encapsulation mode and



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   exchange of the uplink and downlink GRE keys is defined in [9].  It
   is also possible to use the static fixed GRE keys for M-Tunnel.

4.2.  M-Tunnels Connecting to Multiple PIM-SM Routers and ECMP Routing

   There can be multiple LMAs in a PMIPv6-Domain each serving a
   different group of mobile nodes.  In that case, a MAG will connect to
   multiple LMAs with different M-Tunnels having different GRE keys.
   For example, in Figure 5, MAG1 establishes two M-Tunnels with LMA1
   and LMA2, and MAG2 establishes one M-Tunnel with LMA2.

   A MAG that has multiple M-Tunnels, such as MAG1 in Figure 5, must
   decide a single upstream M-Tunnel interface for an RP or a source
   address or prefix.  There are two ways to decide a single upstream
   M-Tunnel for a MAG.  One is only with static MRIB configuration by
   operation.  For example, operators can configure each M-Tunnel
   interface as the RPF interface for specific source adddress(es) or
   prefix(es) one by one.  Each M-Tunnel interface is then inserted into
   the MAG's MRIB and used for different source adddress(es) or
   prefix(es).

   The other way to select a single upstream M-Tunnel interface is with
   PIM ECMP [14].  A MAG enabling PIM routing functions selects a path
   in the ECMP based on its own implementation specific choice, which
   may refer to the description in [14].  The PIM ECMP function chooses
   the PIM neighbor with the highest IP address, or picks the PIM
   neighbor with the best hash value over the destination and source
   addresses.  When operators decide to use PIM ECMP to select a single
   upstream M-Tunnel from multiple M-Tunnels, both MAG and the tunnel
   end-point PIM-SM routers (e.g., LMAs) MUST enable PIM ECMP.





















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                         +----+         +----+
                         |LMA1|         |LMA2|
                         +----+         +----+
                           ||            || ||
                           ||            || ||
                           \\   M-Tunnel // \\
                            \\     |    //   \\
                             \\    +-> //     \\ <-- M-Tunnel
                M-Tunnel ---> \\      //       \\
               (encapsulating  \\    //         \\
               with GRE header) \\  //           \\
                                || ||            ||
                               +----+          +----+
                               |MAG1|---{MN2}  |MAG2|
                               +----+          +----+
                                 |               |
                                 |               |
                               {MN1}           {MN3}

            Figure 5: M-Tunnels established between LMA and MAG


5.  Local Mobility Anchor Operation

   The LMA is responsible for maintaining the mobile node's reachability
   state and is the topological anchor point for the mobile node's home
   network prefix(es).  This document assumes that the LMA is capable of
   forwarding multicast packets to the MAG by enabling the Protocol-
   Independent Multicast - Sparse Mode (PIM-SM) multicast routing
   protocol [3].  The LMA acting as a PIM-SM multicast router may serve
   MAGs as downstream routers for some multicast channels when a mobile
   node is a multicast data receiver (or as upstream routers when a
   mobile node is a multicast data sender).  The downstream (or
   upstream) MAG is connected to the LMA through the M-Tunnel for
   multicast communication.

   When the LMA sets up the multicast state and joins the group as the
   MAG's upstream router, the multicast packets are tunneled to the MAG
   that requested to receive the corresponding multicast session.  The
   MAG then forwards the packets to the mobile node according to the
   multicast listener state maintained in the MAG. [1] supports only
   point-to-point access link types for MAG and mobile node connection;
   hence a mobile node and the MAG are the only two nodes on an access
   link, where the link is assumed to be multicast capable.







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6.  Mobile Access Gateway Operation

   The MAG is the entity that performs the mobility management on behalf
   of a mobile node.  This document assumes that the MAG is PIM-SM
   capable and forwards multicast packets to the corresponding mobile
   nodes attached to MAG by enabling the PIM-SM multicast routing
   protocol.  In addition, the MAG must maintain multicast membership
   status for the attached mobile nodes at the edge and forwards the
   multicast data to the member mobile nodes.  This condition requires
   MAG to support MLDv2 [7] or LW-MLDv2 [8], as well.

   When mobile nodes subscribe multicast channel(s), they send MLD
   Report messages with their link-local address to the MAG, and the MAG
   sends the corresponding PIM Join messages to the upstream router if
   the MAG has no multicast state for the requested channel(s).  The
   upstream router is selected by the Reverse Path Forwarding (RPF)
   lookup algorithm, and that is either the LMA or an adjacent multicast
   router attached to the same link.  If the LMA is the upstream router
   for the channel(s) for the MAG, the MAG encapsulates PIM Join
   messages using the M-Tunnel.

   The MAG also sends MLD Query messages to attached mobile nodes to
   maintain up-to-date membership states.  Since the MAG may deal with a
   large number of the downstream mobile nodes, the MLD protocol
   scalability should be taken into account as described in [13].
   Therefore it is RECOMMENDED that the explicit tracking function [15]
   is enabled on the MAG.

   The optimal multicast routing path may not include the LMA,
   especially in localized routing as described in Section 6.10.3 of [1]
   and [10].  The localized routing option is designed to support node-
   to-node communication within PMIPv6-Domain where a local content
   source exists.  Details are described in Section 8.


7.  Mobile Node Operation

   Mobile nodes attached to the MAG can behave as regular receiver
   hosts.  A mobile node sends MLD report messages to the MAG when it
   wants to subscribe and unsubscribe IP multicast channels.

   In order to subscribe/unsubscribe multicast channel(s) by unsolicited
   report messages and inform current membersip state by solicited
   report messages, mobile nodes MUST support either MLDv1 [7], MLDv2
   [7], or LW-MLDv2 [8], and SHOULD support MLDv2 or LW-MLDv2.






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8.  Localized Multicast Routing

   Localized routing defined in [10] allows mobile nodes attached to the
   same or different MAGs to directly exchange unicast traffic by using
   localized forwarding or a direct tunnel between the MAGs.  Localized
   routing must be initiated both MAG and LMA.  Localized routing is not
   persistent, and is initiated by two signaling messages, Localized
   Routing Initiation (LRI) and Local Routing Acknowledgment (LRA), sent
   by LMA or MAG.

   To support localized multicast routing with PIM-SM capable LMA and
   MAG, both LMA and MAG MUST include the routes orgzanized by the
   localized routing procedure specified in [10] into their MRIBs.  The
   exact mechanism to do this is not specified in this document and is
   left open for implementations and specific deployments.

   To support localized routing for the case that a source node and a
   receiver node are attached to different MAGs but the same LMA (as
   seen in Section 6 of [10]), these MAGs must use the same tunneling
   mechanism for the data traffic tunneled between them.  M-Tunnel
   defined in this document corresponds to the concept; these MAGs
   establish M-Tunnel and enable localized multicast routing.


9.  Smooth Handover

   The MAG is responsible for detecting the mobile node's movements to
   and from the access link and for initiating binding registrations to
   the mobile node's LMA.  In PMIPv6, it does not require for mobile
   nodes to initiate to re-subscribe multicast channels, and the MAG
   keeps multicast channel subscription status for mobile nodes even if
   they move to a different MAG (i.e., n-MAG) in PMIPv6-Domain.

   The MAG needs to join the multicast delivery tree when an attached
   mobile node subscribes a multicast channel.  When the mobile node
   changes the network, it seamlessly receives multicast data from the
   new MAG according to the multicast channel information stored in the
   "MN's Policy Profile" or by some handover mechanisms such as [16] and
   [17].  Whether the MN's Policy Profile or a hondover mechanism mobile
   operators use depend on their policy or implementation.

   Here, a handover procedure using the MN's Policy Profile is described
   as an example.  When the multicast channel information subscribed by
   mobile nodes is maintained in "MN's Policy Profile" stored in a
   policy store [1], the MAG can use the channel information to provide
   seamless handover.  The procedures are described as follows and
   illustrated in Figure 6;




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   1.   Figure 6 shows the examples that a mobile node has received
        multicast data from an upstream multicast router via p-MAG (*1)
        and from LMA via p-MAG (*2).

   2.   Whenever the mobile node moves a new network and attaches to
        n-MAG, the n-MAG obtains the MN-Identifier (MN-ID) and learns
        multicast channel information described in Mobile Node's Policy
        Profile associated to this MN-Identifier.  Describing the method
        how the n-MAG identifies the p-MAG is out of scope of this
        document, while using the same mechanism described in [18] would
        be one of the possible methods.

   3.   If there are multicast channels the mobile node has subscribed
        but the n-MAG has not yet subscribed, n-MAG joins the
        corresponding multicast channels by sending the PIM Join message
        to its upstream router.  If the upstream router is the LMA, the
        PIM messages are encapsulated and transmitted over the M-Tunnel
        (*4); otherwise the PIM messages are sent natively to the
        adjacent upstream router (*3).

   4.   The multicast data is forwarded from the LMA through the
        M-Tunnel between the LMA and n-MAG (*4) or from the adjacent
        upstream router (*3).




























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    MN            p-MAG                LMA                n-MAG
     |              |                   |                   |
     |--MLD Report->|                   |                   |
     |              |---> PIM Join (*1)                     |
     |              |   PIM Join (*2)   |                   |
     |              |==== M-Tunnel ====>|                   |
     |              |                   |---> PIM Join (*2)
     |              |                   |                   |
     |<--Multicast--|                   |                   |
     |   data (*1)  |                   |                   |
     |              |Multicast data (*2)|                   |
     |<-------------|<=== M-Tunnel =====|                   |
     |              |                   |                   |
   Detach           |                   |                   |
     |              |                   |                   |
   Attach           |                   |                   |
     |              |                   |          MN attachment event
     |              |                   |     (Acquire MN-ID and Profile)
     |-------------------------RS-------------------------->|
     |              |                   |                   |
     |              |                   |<-------PBU--------|
     |              |                   |                   |
     |              |                   |--------PBA------->|
     |              |                   |                   |---> PIM Join (*3)
     |              |                   |   PIM Join (*4)   |
     |              |                   |<==== M-Tunnel ====|
     |              |                   |                   |
     |<------------------------RA---------------------------|
     |              |                   |                   |
     |              |      Multicast data (*3)              |
     |<-----------------------------------------------------|
     |              |                   |Multicast data (*4)|
     |              |                   |==== M-Tunnel ====>|
     |<-----------------------------------------------------|
     |              |                   |                   |

                Figure 6: Handover with MN's Policy Profile

   After MN attaches to n-MAG, the multicast data will be delivered to
   the MN immediately.  MN's multicast membership state is maintained
   with MLD Query and Report messages exchanged by MN and n-MAG.  If
   p-MAG thinks that the moving mobile node is the last member of
   multicast channel(s) (according to the membership record maintained
   by the explicit tracking function [15]), p-MAG confirms it by sending
   MLD query.  After the confirmation, p-MAG leaves the channel(s) by
   sending the PIM Prune message to its upstream router.





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10.  IANA Considerations

   This document has no actions for IANA.


11.  Security Considerations

   TBD.


12.  Acknowledgements

   Many of the specifications described in this document are discussed
   and provided by the multimob mailing-list.


13.  References

13.1.  Normative References

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

   [2]   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.

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

   [4]   Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. Traina,
         "Generic Routing Encapsulation (GRE)", RFC 2784, March 2000.

   [5]   Bradner, S., "Key words for use in RFCs to indicate requirement
         levels", RFC 2119, March 1997.

   [6]   Holbrook, H. and B. Cain, "Source-Specific Multicast for IP",
         RFC 4607, August 2006.

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

   [8]   Liu, H., Cao, W., and H. Asaeda, "Lightweight Internet Group
         Management Protocol Version 3 (IGMPv3) and Multicast Listener
         Discovery Version 2 (MLDv2) Protocols", RFC 5790,
         February 2010.



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

   [10]  Krishnan, S., Koodli, R., Loureiro, P., Wu, Q., and A. Dutta,
         "Localized Routing for Proxy Mobile IPv6", RFC 6705,
         September 2012.

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

13.2.  Informative References

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

   [13]  Asaeda, H., Liu, H., and Q. Wu, "Tuning the Behavior of the
         Internet Group Management Protocol (IGMP) and Multicast
         Listener Discovery (MLD) for Routers in Mobile and Wireless
         Networks", RFC 6636, May 2012.

   [14]  Thaler, D. and C. Hopps, "Multipath Issues in Unicast and
         Multicast Next-Hop Selection", RFC 2991, November 2000.

   [15]  Asaeda, H. and N. Leymann, "IGMP/MLD-Based Explicit Membership
         Tracking Function for Multicast Routers",
         draft-ietf-pim-explicit-tracking-02.txt (work in progress),
         October 2012.

   [16]  Contreras, LM., Bernardos, CJ., and I. Soto, "PMIPv6 multicast
         handover optimization by the Subscription Information
         Acquisition through the LMA (SIAL)",
         draft-ietf-multimob-fast-handover-01.txt (work in progress),
         July 2012.

   [17]  von Hugo, D. and H. Asaeda, "Context Transfer Protocol
         Extension for Multicast",
         draft-vonhugo-multimob-cxtp-extension-02.txt (work in
         progress), August 2012.

   [18]  Yokota, H., Chowdhury, K., Koodli, R., Patil, B., and F. Xia,
         "Fast Handovers for Proxy Mobile IPv6", RFC 5949,
         September 2010.







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Authors' Addresses

   Hitoshi Asaeda
   National Institute of Information and Communications Technology
   4-2-1 Nukui-Kitamachi
   Koganei, Tokyo  184-8795
   Japan

   Email: asaeda@nict.go.jp


   Pierrick Seite
   France Telecom
   4, rue du Clos Courtel
   BP 91226, Cesson-Sevigne  35512
   France

   Email: pierrick.seite@orange-ftgroup.com

































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