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Versions: 00                                                            
Network Working Group                                          Seil Jeon
Internet-Draft                                  Univ. of Soongsil, Korea
Expires: August 14, 2008                                    Younghan Kim
                                                Univ. of Soongsil, Korea
                                                       February 14, 2008

              Fast Route Optimization for PMIPv6 handover

Status of this Memo

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Copyright Notice

   Copyright (C) The IETF Trust (2008).

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   To solve the inefficient route problem of PMIPv6, a variety of
   mechanisms were proposed. The mechanism was also proposed to support
   PMIPv6 RO handover according mobile node's movements. Efficient
   PMIPv6 RO handover SHOULD be considered to reduce handover latency
   and to support communication with route optimization disabled mobile
   node's remote node. In this draft, we proposed a mechanism that can
   solve handover latency in PMIPv6 RO handover. And we introduce a few
   of messages to apply proposed mechanism.

Table of Contents

   1. Introduction.....................................................3
   2. Terminology and Functional Components............................3
   3. Protocol Operation...............................................5
   4. Message Formats..................................................6
   5. IANA Considerations..............................................6
   6. Security Considerations..........................................6
   7. Acknowledgment...................................................7
   8. References.......................................................7
     8.1. Normative References.........................................7
   Author's Address....................................................8
   Full Copyright Statement............................................9
   Intellectual Property and Copyright Statements......................9

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1. Introduction

   In PMIPv6 domains[2], all data packets will always traverse a MN's
   MAG and its LMA irrespective of location of the MN's remote node.
   This results high packet delivery latency. To solve this problem, a
   mechanism to provide an optimal route between two MNs within the same
   PMIPv6 domain was proposed[3]. And they include the method, thiat is
   called PMIPv6 RO handover, to support route optimization considering
   MN's frequent movements. But, in this mechanism, packet resumption
   latency with MN's remote node is not considered. In order to solve
   the problem, we propose a mechanism that Fast Route Optimizaiton. It
   also supports RO-disabled MN's remote node due to operator's policy.

2. Terminology and Functional Components

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC 2119 [1].

   o  Mobile Node (MN)

   o  Route Optimization (RO)

   o  Previous Mobile Access Gateway (pMAG) - 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 (nMAG) - The MAG that manages mobility
      related signaling for the MN after handover

   o  Mobile node's LMA (mnLMA)

   o  Correspondent node's MAG (cnMAG)

   o  Correspondent node's LMA (cnLMA)

   o  Fast Route Optimization (FRO) - The mechanism to reduce handover
      latency mobile node will experice after mobile node's PMIPv6 RO

   o  FRO Init - It is used to know whether MN's remote node is

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      supporting FRO or not.

   o  FRO Update - It is used to create MAG-to-MAG tunnel between nMAGs
      and cnMAG.

   o  FRO Advertisement - It is used to notify to cnMAG that the fact MN
      is arrived to current MAG. As soon as cnMAG receives this message,
      the packet delivered after changing destination IP of tunnel
      interface without ack.

   o  FRO Complete - It is used to update cnLMA that the fact changed
      MN's information.

   o  Context Transfer (CT) - It is transmitted by pMAG forecasting MN's
      destination nMAG. This message include MN ID, MN home network
      prefix and cnMAG IP. The nMAG performs FRO Update with cnMAG.

                             ---- Internet Backbone ----
                            :                          :
                            :                          :
                            |                          |
                        +-------+                    +-------+
                        | mnLMA |--------------------| cnLMA |
                        +-------+                    +-------+
                            |                            |
                            |                            |
                            +-------+                    |
                            |       |                    |
             +------+    +----+    +------+           +-------+
             |nMAG_1|    |pMAG|    |nMAG_2|           | cnMAG |
             +------+    +----+    +------+           +-------+
                           :                             :
                         +----+                        +----+
                         | MN | ----->                 | CN |
                         +----+                        +----+

      Figure 1: Reference architecture for fast route optimization in
      PMIPv6 domain

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3. Protocol Operation

      nMAG_1      pMAG        mnLMA       nMAG_2      cnLMA       cnMAG
        |           |           |           |           |           |
        |     Link_Going_Down   |           |           |           |
        |           |-FRO Init->|           |           |           |
        |           |           |------ FRO Init ------>|           |
        |           |           |           |           |           |
        |           |           |<---- FRO Init Ack ----|           |
        |           |<-FRO Init-|           |           |           |
        |           |      Ack  |           |           |           |
        |           |           |           |           |           |
        |       Disconnect      |           |           |           |
        |<--- CT ---|--- CT --->|           |           |           |
        |           |           |           |           |           |
        |--------------------- FRO Update ------------------------->|
        |           |           |           |           |           |
        |           |           |           |----- FRO Update ----->|
        |           |           |           |           |           |
        |<-------------------- FRO Update Ack ----------------------|
        |           |           |           |           |           |
        |           |           |           |<---- FRO Update Ack --|
        |           |           |           |           |           |
        |           |           |      MN_Attach        |           |
        |           |           |<-- PBU ---|-- FRO Advertisement-->|
        |           |           |           |           |           |
        |           |           |--- PBA -->|=======================|
        |           |           |           |    packet delivered   |
        |           |           |           |   via optimized route |
        |           |           |           |           |           |
        |           |           |           |           |<-- FRO ---|
        |           |           |           |           | Complete  |
        |           |           |           |           |           |
        |           |           |           |           | --FRO --->|
        |           |           |           |           | Complete  |
        |           |           |           |           |   Ack     |
        |           |           |           |           |           |

        Figure 2: Fast Route Optmization for PMIPv6 handover procedure

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   The pMAG initiate the FRO Init process by L2 trigger, which notify
   link will be down. The link event information indicates the MN will
   soon be handed over from one MAG to another MAG. Then, mnLMA transmit
   FRO Init to the cnLMA. If the cnLMA does not support FRO due to oper-
   ator's policy, the cnLMA responds to mnLMA FRO rejection. As soon as
   the pMAG receives L2 trigger that current MN's link is disconnected,
   pre-updating processes are performed.

   The nMAGs which received handover context message perform FRO Update
   to establish nMAGs-to-cnMAG tunnel. After that, MN ID is created in
   FRO binding list table. The nMAGs have timer to count from the time
   received FRO Update Ack to the time MN is handed over. If MN handed
   over the nMAG_2 of them, the nMAG_2 detecting MN's attachment trans-
   mits Proxy Binding Update to mnLMA. At once, the nMAG_2 sends FRO
   Advertisement to the cnMAG if received MN ID is in FRO binding list
   table. After that, a MAG-to-MAG tunnel activated between nMAG_2 and
   cnMAG. If the other nMAGs does not receive L2 signal notifying MN's
   arrival, pre-established tunnel and MN ID in FRO binding list table
   are deleted. Since FRO Ack process has been completed, data communi-
   cation is available using optimized route. And FRO Complete procedure
   is performed to inform the result of MN's handover to each LMA. So, a
   MN can reduce communication resumption latency.

4. Message Formats

   To suit the format of the Proxy MIPv6 messages, FRO Init, FRO Update
   and FRO Advertisement, FRO Complete messages are encoded according to
   the message data encoding rules for the Mobility Header (MH) as spec-
   ified in [RFC3775]. Messages for RO are extensions to [I-D.ietf-
   netlmm-proxymip6] and identified by the MH Type. Parameters being
   carried by any of these messages are encoded as message options
   according to the type-length-value format specified in [RFC3775].
   Specified about the message and message option format are TBD.

5. IANA Considerations


6. Security Considerations

   This document does not discuss any special security concerns in
   detail.  The protocol of this document is built on the assumption

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   that all participating nodes are trusted each other as well as there
   is no adversary who modifies/injects false messages to corrupt the

7. Acknowledgment

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

8. References

   8.1. Normative References

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

[2]  Gundavelli, S., "Proxy Mobile IPv6", draft-ietf-netlmm-proxymip6-10
     (work in progress), February 2008.

[3]  Abeill, J., "Route Optimization for Proxy Mobile IPv6", draft-
     abeille-netlmm-proxymip6ro-01 (work in progress), November 2007.

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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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Full Copyright Statement

   Copyright (C) The IETF Trust (2008).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an

Intellectual Property Statement

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