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Versions: 00                                                            
DNA Working Group                                              R. Koodli
Internet-Draft                                     Nokia Research Center
Expires: January 9, 2006                                  S. Madanapalli
                                                             Samsung ISO
                                                            July 8, 2005

                     FMIPv6 Usage with DNA Protocol

Status of this Memo

   This document is an Internet-Draft and is subject to all provisions
   of Section 3 of RFC 3667.  By submitting this Internet-Draft, each
   author represents that any applicable patent or other IPR claims of
   which he or she is aware have been or will be disclosed, and any of
   which he or she becomes aware will be disclosed, in accordance with
   Section 6 of BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on January 9, 2006.

Copyright Notice

   Copyright (C) The Internet Society (2005).


   In this document, we describe how the Fast Mobile IPv6 Handovers
   (FMIPv6) protocol can work where DNA protocol support is available,
   but the neighborhood information, which is part of the FMIPv6
   operation, is not available.

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Table of Contents

   1.   Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.   FMIPv6 Operating Modes . . . . . . . . . . . . . . . . . . . . 3
   3.   FMIPv6 with DNA  . . . . . . . . . . . . . . . . . . . . . . . 4
   4.   Protocol Operation . . . . . . . . . . . . . . . . . . . . . . 4
   5.   IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 5
   6.   Security Considerations  . . . . . . . . . . . . . . . . . . . 5
   7.   Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
   8.   References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
        Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 6
        Intellectual Property and Copyright Statements . . . . . . . . 7

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1.  Introduction

   The Fast Handovers for Mobile IPv6 [1] defines a protocol to reduce
   delay and packet loss from IP protocol operations during a handover
   between cells or points of attachment.  These protocol operations
   include movement detection, IP configuration and location update with
   a distant mobility agent such as a Home Agent.  The FMIPv6 protocol
   is designed to effectively eliminate the delays due to movement
   detection and IP configuration latencies, while disengaging the
   location update latency from the time-critical path so that
   applications such as Voice over IP are provided real-time mobility

   The Detecting Network Attachment (DNA) WG is designing protocols to
   quickly detect link changes and enable establishment of IP
   connectivity as soon as a mobile node is attached to a new subnet.
   Compared to existing IPv6 router discovery mechanisms, DNA protocols
   provide faster and reliable mechanisms for determining the link
   identity and router discovery on the new subnet.  DNA routers send
   augmented Router Advertisement information which uniquely identifies
   a link.  These RAs are sent without delay providing rapid
   notification of link change.  A host implementing DNA mechanisms
   determines the subnet change and configures new care of address
   significantly faster than non-DNA (unmodified) hosts on networks with
   DNA support, if post arrival link change detection is required.

   The purpose of this document is to illustrate how the FMIPv6 protocol
   could make use of the DNA protocol to retain the desired handover
   performance in certain circumstances.  In order to do that, some
   background on the two operating modes of the FMIPv6 protocol is

2.  FMIPv6 Operating Modes

   The FMIPv6 protocol can effectively eliminate the movement detection
   and IP configuration latencies when knowledge of the neighborhood
   access points and their subnet affiliation is available.  For
   instance, a Mobile Node can query its access router to provide the
   subnet prefix, IP address and MAC address of a target router attached
   to a neighboring access point.  With this information, it builds a
   neighborhood map of Access Point Identifier to Access Router
   Information.  So, a conceptual neighborhood data structure consists
   of [AP-ID, AR-Info] tuples, with each AR-Info structure consisting of
   a router's IP address, MAC address and subnet prefix corresponding to
   the interface to which the Access Point is attached to.  Such a
   neighborhood data structure serves two purposes:  First, it allows a
   MN to map an association to a new radio connection to subnet
   information immediately, which allows it to bypass router discovery.

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   Second, it allows a MN to use a new IP address on the new subnet link
   immediately, which allows it to send data packets immediately.

   There are two modes of operation assuming neighborhood information.
   In the "predictive mode", a MN is able to effect a local route update
   before departing from its current link.  That is, a MN updates its
   access router's route table to forward packets to the new IP address
   before the MN departs the current link.  In the "reactive" mode, the
   MN effects such a route update after it regains radio connectivity on
   the new link.  In both the cases, the latencies due to movement
   detection and IP configuration are eliminated.  In some cases
   however, neighborhood information may not be available.  We discuss
   this in the following section.

3.  FMIPv6 with DNA

   There are scenarios where DNA protocol operation could be beneficial
   for FMIPv6.  For instance, an access network may not be able to
   provide neighborhood information for whatever reasons, or a MN may
   end up on an unanticipated Access Point for which it has no
   neighborhood information available.  In another scenario, the
   neighborhood information maintained could be marked as stale using
   some measure.  Under these scenarios, if DNA protocol is available,
   it can expedite FMIPv6 handover.

   When a MN with no neighborhood information regains link connectivity,
   it performs DNA movement detection to check if it has changed IP
   subnet.  DNA performs router discovery, and in the process learns new
   subnet prefixes and router addresses.  Subsequently, it runs address
   configuration, and uses Optimistic DAD [2], and sends the FMIPv6 Fast
   Binding Update (FBU) message to its previous access router (PAR).
   This special-case of reactive handover is expected to be faster than
   having to perform these operations in the absence of DNA protocol

4.  Protocol Operation

   The following are the steps that take place when an MN with no
   neighborhood information attaches to an AP.
   1.  MN (re)associates with an Access Point (AP) and gets the AP-ID
   2.  The MN searches for the [AP-ID, AR info] Tuple in its
       neighborhood data structure corresponding to the AP-ID of the
       Access Point it just (re)associated.  If [AP-ID AR info] is
       available, MN proceeds with the rest of the FMIPv6 protocol.  If
       the tuple info is not available, it invokes the DNA protocol (see

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   3.  The MN sends a Router Solicitation with DNA options (if any) to
       determine if there is a subnet change and to acquire new prefixes
       on the subnet.
   4.  The MN receives a DNA Router Advertisement, determines change in
       subnet, configures new care of address and makes the address
       optimistic [2].
   5.  The MN sends a Fast Binding Update (FBU) to the Previous Access
       Router (PAR) directly without being encapsulated in FNA.
   6.  The PAR should send a Handover Initiate (HI) message to the New
       Access Router (NAR).
   7.  The NAR should send a Handover Acknowledge (HAck) message to the
   8.  The PAR sends a Fast Binding Acknowledgement (FBack) message to
       the MN on the new link.
   9.  The PAR starts tunneling the packets to the MN's new CoA.

5.  IANA Considerations

   There are no IANA considerations introduced by this draft.

6.  Security Considerations

   This draft is informational.  Nevertheless, the security
   considerations of the FMIPv6 protocol and the DNA protocol must be
   taken into account.  For instance, the FBU message mentioned above
   needs to be protected using a security association between the MN and
   the PAR.  Similar considerations apply for the DNA protocols which
   may be able to take advantage of SEND for Router Discovery, if
   available [3].

7.  Acknowledgements

   The authors would like to thank Greg Daley for his initiative, and
   suggestions to improve this draft.

8.  References

   [1]  Koodli, R., "Fast Handovers for Mobile IPv6,
        draft-ietf-mipshop-fast-mipv6-03.txt (work in progress)",
        October 2004.

   [2]  Moore, N., "Optimistic Duplicate Address Detection for IPv6,
        draft-ietf-ipv6-optimistic-dad-05.txt (work in progress)",
        February 2005.

   [3]  Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
        Neighbor Discovery (SEND)", RFC 3971, March 2005.

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Authors' Addresses

   Rajeev Koodli
   Nokia Research Center
   313 Fairchild Drive
   Mountain View, CA 94043 USA

   Phone: +1 650 625 2359
   Email: Rajeev.Koodli@nokia.com

   Syam Madanapalli
   Samsung ISO
   No. 3/1 Millers Road
   Bangalore-560 052, India

   Phone: +91 80 51197777
   Email: syam@samsung.com

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   Copyright (C) The Internet Society (2005).  This document is subject
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