One document matched: draft-ietf-multimob-pmipv6-source-00.xml


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<rfc category="std" docName="draft-ietf-multimob-pmipv6-source-00"
     ipr="trust200902">
  <front>
    <title abbrev="Multicast Senders in PMIPv6">Mobile Multicast Sender
    Support in Proxy Mobile IPv6 (PMIPv6) Domains</title>

    <author fullname="Thomas C. Schmidt" initials="T C."
            surname="Schmidt, Ed.">
      <organization>HAW Hamburg</organization>

      <address>
        <postal>
          <street>Berliner Tor 7</street>

          <city>Hamburg</city>

          <code>20099</code>

          <country>Germany</country>
        </postal>

        <email>schmidt@informatik.haw-hamburg.de</email>

        <uri>http://inet.cpt.haw-hamburg.de/members/schmidt</uri>
      </address>
    </author>

    <author fullname="Shuai Gao" initials="S." surname="Gao">
      <organization>Beijing Jiaotong University</organization>

      <address>
        <postal>
          <street></street>

          <city>Beijing</city>

          <region></region>

          <code></code>

          <country>China</country>
        </postal>

        <phone></phone>

        <facsimile></facsimile>

        <email>shgao@bjtu.edu.cn</email>

        <uri></uri>
      </address>
    </author>

    <author fullname="Hong-Ke Zhang" initials="H." surname="Zhang">
      <organization>Beijing Jiaotong University</organization>

      <address>
        <postal>
          <street></street>

          <city>Beijing</city>

          <region></region>

          <code></code>

          <country>China</country>
        </postal>

        <phone></phone>

        <facsimile></facsimile>

        <email>hkzhang@bjtu.edu.cn</email>

        <uri></uri>
      </address>
    </author>

    <author fullname="Matthias Waehlisch" initials="M." surname="Waehlisch">
      <organization>link-lab & FU Berlin</organization>

      <address>
        <postal>
          <street>Hoenower Str. 35</street>

          <city>Berlin</city>

          <code>10318</code>

          <country>Germany</country>
        </postal>

        <email>mw@link-lab.net</email>
      </address>
    </author>

    <date />

    <workgroup>MULTIMOB Group</workgroup>

    <abstract>
      <t>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.</t>
    </abstract>

    <note title="Requirements Language">
      <t>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 <xref
      target="RFC2119">RFC 2119</xref>.</t>
    </note>
  </front>

  <middle>
    <section title="Introduction">
      <t>Proxy Mobile IPv6 (PMIPv6) <xref target="RFC5213"></xref> extends
      Mobile IPv6 (MIPv6) <xref target="RFC6275"></xref> 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 <xref
      target="RFC5213"></xref>, cannot participate in multicast communication,
      as MAGs will discard group packets.</t>

      <t>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 <xref
      target="RFC6224"></xref>. 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.</t>

      <t>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.</t>

      <t>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.</t>

      <t>This document describes the support of mobile multicast senders in
      Proxy Mobile IPv6 domains subsequently for the base deployment scenario
      <xref target="RFC6224"></xref>, 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 <xref target="RFC5757"></xref>. Mobile Nodes in
      this setting remain agnostic of multicast mobility operations.</t>
    </section>

    <section title="Terminology">
      <t>This document uses the terminology as defined for the mobility
      protocols <xref target="RFC6275"></xref>, <xref target="RFC5213">
      </xref> and <xref target="RFC5844"></xref>, as well as the multicast
      edge related protocols <xref target="RFC3376"></xref>, <xref
      target="RFC3810"></xref> and <xref target="RFC4605"></xref>.</t>
    </section>

    <section anchor="Base"
             title="Base Solution for Source Mobility and PMIPv6 Routing">
      <section title="Overview">
        <t>The reference scenario for multicast deployment in Proxy Mobile
        IPv6 domains is illustrated in <xref target="fig1"></xref>. 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.</t>

        <figure anchor="fig1"
                title="Reference Network for  Multicast Deployment in PMIPv6 with Source Mobility">
          <artwork><![CDATA[
                       +-------------+
                       | 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)
      ]]></artwork>
        </figure>

        <t>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).</t>

        <t>An MN can successfully distribute multicast data in PMIPv6, if MLD
        proxy functions are deployed at the MAG as described in <xref
        target="RFC6224"></xref>. 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.</t>

        <t>According to the specifications given in <xref
        target="RFC4605"></xref>, 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.</t>

        <t>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.</t>

        <t><list style="numbers">
            <t>The MAG has determined that the MN is admissible to multicast
            services.</t>

            <t>The MAG has added the new downstream link to the MLD proxy
            instance with up-link to the corresponding LMA.</t>
          </list>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 <xref target="fig-callflow"></xref>). In this
        way, multicast source mobility is transparently enabled in PMIPv6
        domains that deploy the base scenario for multicast.</t>

        <figure anchor="fig-callflow"
                title="Call Flow for Group Communication in Multicast-enabled PMIP">
          <artwork><![CDATA[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    |                |               |                |
|<---------------+                |               |                |
|                |                |               |                |
]]></artwork>
        </figure>

        <t></t>

        <t>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 <xref
        target="RFC5844"></xref>. IPv4 multicast is handled by an IGMP proxy
        function at the MAG in an analogous way.</t>

        <t>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 <xref target="A-Eval"></xref>
        for further considerations).</t>
      </section>

      <section title="Base Solution for Source Mobility: Details">
        <t>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.</t>

        <section title="Operations of the Mobile Node">
          <t>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.</t>
        </section>

        <section title="Operations of the Mobile Access Gateway">
          <t>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., <xref target="RFC6224"></xref>). 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 <xref
          target="RFC4605"></xref>.</t>

          <t>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.</t>
        </section>

        <section title="Operations of the Local Mobility Anchor">
          <t>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.</t>

          <section anchor="PIM-Source"
                   title="Local Mobility Anchors Operating PIM">
            <t>Local Mobility Anchors that operate the PIM-SM routing protocol
            <xref target="RFC4601"></xref> 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.</t>

            <t>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 <xref
            target="RFC4601"></xref> ).</t>

            <t>Notably, running BIDIR PIM <xref target="RFC5015"></xref> on
            LMAs remains robust with respect to source location and does not
            require a special configuration.</t>
          </section>
        </section>

        <section title="IPv4 Support">
          <t>An MN in a PMIPv6 domain may use an IPv4 address transparently
          for communication as specified in <xref target="RFC5844"></xref>.
          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. <xref target="RFC4605"></xref> defines
          IGMP proxy behaviour in full agreement with IPv6/MLD. Thus IPv4
          support can be transparently provided following the obvious
          deployment analogy.</t>

          <t>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.</t>

          <t>A particular note is worth giving the scenario of <xref
          target="RFC5845"></xref> 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.</t>

          <t>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-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.</t>
        </section>

        <section title="Efficiency of the Distribution System">
          <t>In the following efficiency-related issues are enumerated.</t>

          <t><list style="hanging">
              <t hangText="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.</t>

              <t hangText="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.</t>
            </list></t>
        </section>
      </section>
    </section>

    <section anchor="Direct-Routing" title="Direct Multicast Routing">
      <t>There are deployment scenarios, where multicast services are
      available throughout the access network independent of the PMIPv6
      routing system <xref target="I-D.zuniga-multimob-pmipv6-ropt"></xref>.
      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 <xref target="Extensions"></xref>
      for a further discussion).</t>

      <section title="Overview">
        <t>Direct multicast access can be supported by <list style="symbols">
            <t>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,</t>

            <t>a multicast routing protocol such as PIM-SM <xref
            target="RFC4601"></xref> or BIDIR-PIM <xref
            target="RFC5015"></xref> deployed at the MAGs.</t>
          </list></t>

        <figure anchor="fig2"
                title="Reference Networks for (a) Proxy-assisted Direct Multicast Access and (b) Dynamic Multicast Routing at MAGs">
          <artwork><![CDATA[        
               ***  ***  ***  ***
              *   **   **   **   *
             *                    *
             *      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
      ]]></artwork>
        </figure>

        <t><xref target="fig2"></xref> 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.</t>

        <t>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
        <xref target="RFC5757"></xref> for further aspects). Deployment
        details are specific to the multicast routing protocol in use, in the
        following described for common protocols.</t>
      </section>

      <section title="MLD Proxies at MAGs">
        <t>In a PMIPv6 domain, single MLD proxy instances can be deployed at
        each MAG to enable multicast service at the access (see <xref
        target="fig2"></xref> (a) ). To avoid service disruptions on
        handovers, the uplinks of all proxies SHOULD be adjacent to the same
        next-hop multicast router. This can either be achieved by arranging
        proxies within a flat access network, or by upstream tunnels that
        terminate at a common multicast router.</t>

        <t>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.</t>

        <t>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.</t>

        <section title="PIM-SM Considerations">
          <t>A mobile source that transmits data via an MLD proxy will not be
          directly connected to a PIM Designated Router as discussed in <xref
          target="PIM-Source"></xref>. Countermeasures apply correspondingly.
          </t>

          <t>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.</t>
        </section>

        <section title="SSM Considerations">
          <t>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.</t>
        </section>
      </section>

      <section title="PIM-SM">
        <t>TODO</t>
      </section>

      <section title="BIDIR PIM">
        <t>TODO</t>
      </section>
    </section>

    <section anchor="Extensions"
             title="Extended Source Mobility Schemes in PMIPv6">
      <t>In this section, specific optimization approaches to multicast source
      mobility are introduced.</t>

      <section title="Multiple Upstream Interface Proxy">
        <t>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 <xref target="RFC6224"></xref> 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).</t>

        <t>.... TODO details.</t>
      </section>
    </section>

    <section anchor="IANA" title="IANA Considerations">
      <t>TODO.</t>

      <t>Note to RFC Editor: this section may be removed on publication as an
      RFC.</t>
    </section>

    <section anchor="Security" title="Security Considerations">
      <t>TODO</t>

      <t>Consequently, no new threats are introduced by this document in
      addition to those identified as security concerns of <xref
      target="RFC3810"></xref>, <xref target="RFC4605"></xref>, <xref
      target="RFC5213"></xref>, and <xref target="RFC5844"></xref>.</t>

      <t>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.</t>
    </section>

    <section anchor="Acknowledgements" title="Acknowledgements">
      <t>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.</t>

      <t></t>
    </section>
  </middle>

  <back>
    <references title="Normative References">
      <?rfc include="reference.RFC.2119"?>

      <?rfc include="reference.RFC.6275"?>

      <?rfc include="reference.RFC.5213"?>

      <?rfc include="reference.RFC.3810"?>

      <?rfc include="reference.RFC.4601"?>

      <?rfc include="reference.RFC.4605"?>

      <?rfc include="reference.RFC.5015"?>

      <?rfc include="reference.RFC.2710"?>

      <?rfc include="reference.RFC.5844"?>

      <?rfc include="reference.RFC.3376"?>
    </references>

    <references title="Informative References">
      <?rfc include="reference.RFC.5757"?>

      <?rfc include="reference.RFC.6224"?>

      <?rfc include="reference.RFC.5845"?>

      <?rfc include="reference.RFC.2236"?>

      <?rfc include="reference.I-D.zuniga-multimob-pmipv6-ropt"?>
    </references>

    <section anchor="A-Eval" title="Evaluation of Traffic Flows">
      <t>TODO</t>
    </section>

    <section title="Change Log ">
      <t>The following changes have been made from version
      draft-ietf-multimob-pmipv6-source-00:</t>
    </section>
  </back>
</rfc>

PAFTECH AB 2003-20262026-04-24 10:22:02