Network Working Group                                          Seil Jeon
Internet-Draft                                  Univ. of Soongsil, Korea
Expires: August 23, 2008                                    Younghan Kim
                                                Univ. of Soongsil, Korea
                                                       February 23, 2009


            Mobile Multicasting Support in Proxy Mobile IPv6
                  draft-sijeon-netlmm-mms-pmip6-00.txt

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Abstract

   To support IP-based group communication in mobile such as mobile
   IPTV, IP multicasting is required. Two major constraints in mobile
   multicasting are the tunnel convergence problem and high handover
   latency. To reduce the constraints, several mobile multicasting
   schemes base on Mobile IP have been proposed. To meet requirements,
   we present a multicasting architecture and fast handover scheme for
   Proxy Mobile IPv6 (PMIPv6).


Table of Contents

   1. Introduction.....................................................3
   2. Conventions & Terminology........................................3
   3. PMIPv6 Multicasting Architecture.................................4
   4. Handover Operation...............................................4
   5. Message Formats..................................................5
   6. IANA Considertions...............................................6
   7. Security Considerations..........................................6
   8. Acknowledgment...................................................6
   9. References.......................................................6
     9.1. Normative References.........................................6
   Author's Address....................................................8






















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1. Introduction

   High performance of wireless technologies make multimedia streaming
   service such as IPTV audio/video stream. These services are based on
   group communication, IP multicasting is also required. Traditional IP
   multicast mechanisms including multicast routing and membership
   management protocols have been designed for static hosts [2].
   Moreover, up to now, IP mobility protocol for mobile multicasting
   depends on host-based Mobile IP variants (Mobile IP and Fast Mobile
   IPv6). However, Mobile IP variant protocols require modifications to
   a applied solution on mobile device and IP reconfiguration during
   handoff. The Proxy Mobile IPv6 (PMIPv6) in [3] does not require any
   mobility related protocol and IP reconfiguration in same PMIPv6
   domain. With the strength of PMIPv6, several service solution are
   described in [4]. However, the solution needs to solve two major
   constraints which are the tunnel convergence problem and high
   handover latency [5]. Thus, we present a multicasting architecture
   and fast handover operation considering the requirements for PMIPv6.

2. Terminology and Functional Components

   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 [1].
   o  Mobile Node (MN)

   o  Previous Mobile Access Gateway (P-MAG) - The MAG that manages
      mobility relaged signaling for a MN before handover. In this
      document, a MAG and Access Router (AR) are collocated

   o  New Mobile Access Gateway (N-MAG) - The MAG that manages mobility
      related signaling for the MN after handover

   o  Multicast Router (MR)

   o  MLD Forwarding Proxy (MF-Proxy)


   o  PMIPv6 Multicast Context Transfer (MCT) - It is transmitted by the
      P-MAG forecasting MN's destination to the N-MAG. This message
      include MN ID, MN home network prefix and P-MAG IP address, and
      multicast group address of the MN executing handoff.



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3. PMIPv6 Multicasting Architecture



                                                Multicast Core Tree
                                                          :
                                                          :
                                                          |
                        +----------+                 +----------+
                        |   LMA    |                 | Local MR |
                        +----------+                 +----------+
                             |                            |
                             |-----------------+          |
                             |       |          |
                             |         +------------------|
                             |         |       |          |
                        +----------+      |    |    +----------+
                        |  P-MAG   |---+       +----|  N-MAG   |
                        |(MF-Proxy)|                |(MF-Proxy)|
                        +----------+                +----------+
                             :                           :
                          +------+                    +------+
                          |  MN  |   ----->           |  MN  |
                          +------+                    +------+

           Figure 1: Multicasting architecture in PMIPv6 domain


   To design a PMIPv6-based multicasting services, we should consider
   the position of multicast router (MR). If a LMA contain the MR
   function, it introduces a tunnel convergence problem similar to
   Mobile IP variant bi-directional tunnel schemes. To solve the
   problem, we separate the MR function from the LMA. Moreover, if a MAG
   has a MR function and a local MR is connected with MAGs, the routing
   update overhead degrades the performance of PMIPv6 components due to
   frequent MNs' movement. Thus, Figure 1 shows proposed PMIPv6
   multicasting architecture where the MAG only contains a MLD
   forwarding proxy function using the IGMP/MLD forwarding proxy [6]
   proposed by the IETF. This model can solve the tunnel convergence
   problem and reduce the routing processing overhead.

4. Handover Operation



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          MN         pMAG        nMAG         LMA         MR
   Multicast Tree
           |           |           |           |           |           |
           |           |           |           |           |           |
     Link->|       Handover        |           |           |           |
   Disconnected    Detection       |           |           |           |
           |           |           |           |           |           |
           |           |--PMIPv6-->|           |           |           |
           |           | Multicast |           |           |           |
           |           |  Context  |           |           |           |
           |           |  Transfer |           |           |           |
           |           |           |           |           |           |
           |           |           |-MLD Membership Report>|           |
           |           |           |           |           |           |
           |---- L2 Attachment --->|           |           |           |
           |           |           |           |           |           |
           |           |           |-Proxy Binding Update->|           |
           |           |           |           |           |           |
           |           |           |           |           |           |
           |           |           |<--Proxy Binding Ack.--|           |
           |           |           |           |           |           |
           |           |           |           |           |           |
           |<--------------------------Multicast Data------------------|
           |           |           |           |           |           |
           |           |           |           |           |           |


           Figure 2: Fast multicast handover procedure using PMIPv6

   Directly applying a PMIPv6 handover scheme to the proposed network
   model leads to service disruption due to the latency cased by MLD
   query/report. To solve this problem, we propose a fast handover
   scheme using the context transfer mechanism. Figure 2 shows handover
   operation. When an MN hands off, the MAG with MLD forwarding proxy
   predicts an MN's movement direction and transfers the multicast
   context message, which includes the MN ID, the MN home network
   prefix, the current MAG address, and the multicast group address.
   Then, the N-MAG checks whether it is a receiving node of multicast
   data corresponding to the group requested by the P-MAG. If this is
   not the case, it joins the group by sending a MLD report.

5. Message Formats



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   TBD

6. IANA Considerations

   TBD

7. Security Considerations

   This document does not discuss any special security concerns in
   detail.  The protocol of this document is built on the assumption
   that all participating nodes are trusted each other as well as there
   is no adversary who modifies/injects false messages to corrupt the
   procedures.

8. Acknowledgment

   Funding for the RFC Editor function is provided by the IETF
   Administrative Support Activity (IASA).


9. References

   9.1. Normative References


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


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


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


[4]  Y. K. Zhao, P. Seite, "The Solution for PMIPv6 Multicast Service,"
     draft-zhao-multimob-pmip6-solution-02.txt, November 2008.


[5]  I. Romdhani, M. Kellil, and H. Lach, "IP Mobile Multicast : Chal-
     lenges and Solutions," IEEE Communications Surveys & Tutorials,
     vol. 6, no. 1, pp. 18-41, 2004.





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









































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Author's Addresses

   Seil Jeon
   University of Soongsil in Seoul
   11F Hyungnam Engineering Bldg. 317, Sangdo-Dong,
   Dongjak-Gu, Seoul 156-743 Korea
   Phone: +82 2 814 0151
   E-mail: sijeon@dcn.ssu.ac.kr

   Younghan Kim
   University of Soongsil in Seoul
   11F Hyungnam Engineering Bldg. 317, Sangdo-Dong,
   Dongjak-Gu, Seoul 156-743 Korea
   Phone: +82 2 820 0904
   E-mail: yhkim@dcn.ssu.ac.kr






























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