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Versions: 00 01 02 03 04                                                
   INTERNET-DRAFT                                 Carl Williams, Editor
   Internet Engineering Task Force                            MCSR Labs


   Issued:  March 2, 2003
   Expires: August 2, 2003

                  Localized Mobility Management Requirements
                <draft-ietf-mobileip-lmm-requirements-03.txt>

   Status of This Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC 2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   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.'

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

Abstract

   This document describes requirements for Localized Mobility
   Management (LMM) for Mobile IP and Mobile Ipv6 protocols.
   These requirements are intended to guide the design of a protocol
   specification for LMM.  Localized Mobility Management, in general,
   introduces enhancements to Mobile IPv4 and Mobile IPv6 to
   reduce the amount of latency in binding updates sent to the Home
   Agent and, for route-optimization, Correspondent Nodes, upon
   Care of Address change. In addition, LMM seeks to reduce the
   amount of signaling over the global Internet when a mobile
   node traverses within a defined local domain.  The identified
   requirements are essential for localized mobility management
   functionality. They are intended to be used as a guide for
   analysis on the observed benefits over the identified requirements
   for architecting and deploying LMM schemes.







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Table of Contents

1.0 Introduction ....................................................  2
2.0 Terminology .....................................................  4
3.0 Requirements ....................................................  5
   3.1 Intra-domain mobility ........................................  5
   3.2 Security .....................................................  5
   3.3 Induced LMM functional requirement ...........................  6
   3.4 Scalability, Reliability, and Performance ....................  6
   3.5 Mobility Management Support ..................................  8
   3.6 Auto-configuration capabilities for LMM constituents..........  8
   3.7 Interworking with IP routing infrastructure requirement.......  9
   3.8 Sparse routing element population requirement ................  9
   3.9 Support for Mobile IPv6 Handover .............................  9
   3.10 Simple network design requirement ...........................  9
   3.12 Stability ................................................... 10
   3.13 QoS Requirements ............................................ 10
4.0 Acknowledgments ................................................. 10
5.0 References ...................................................... 11
6.0 Author's Addresses .............................................. 12
7.0 Full Copyright Statement ........................................ 12

1.0 Introduction

   In order to meet the demands of real-time applications and the
   expectations of future wireless users for service level quality
   similar to the one of wireline users, base mobility management in
   IP networks, and in particular Mobile IP and Mobile IPv6 is facing
   a number of technical challenges in terms of performance and scalability.
   These manifest themselves as increased latencies in the control
   signaling between a Mobile Node and its peer entities, namely the
   Home Agent (HA) and its Corresponding Nodes (CNs).

   In the base Mobile IP protocol [6][2], movement between two subnets
   requires that the Mobile Node obtain a new Care of Address in the
   new subnet. This allows the Mobile Node to receive traffic on the
   new subnet. In order for the routing change to become effective,
   however, the Mobile Node must issue a binding update (also known in
   Mobile IPv4 as a Home Agent registration) to the Home Agent so that
   the Home Agent can change the routing from the previous subnet to
   the new subnet. The binding update establishes a host route on the
   Home Agent between the Mobile Node's Home Address and its new Care
   of Address. In addition, if route optimization is in use [2], the
   Mobile Node may also issue binding updates to Correspondent Nodes to
   allow them to send traffic directly to the new Care of Address
   rather than tunneling their traffic through the Home Agent.

   Traffic destined for the Mobile Node is sent to the old Care of
   Address and is, effectively, dropped until the Home Agent processes
   the MIPv6 Binding Update or MIPv4 Home Agent Registration. If the
   Mobile Node is at some geographical and topological distance away

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   from the Home Agent and Correspondent Nodes, the amount of time
   involved in sending the binding updates may be greater than 100
   hundred milliseconds. This latency in routing update may cause
   some packets for the Mobile Node to be lost at the old Access Router.
   This problem has been called "Localized Mobility Management (LMM)".
   Localized mobility management schemes allow the Mobile Node to continue
   receiving traffic on the new subnet without any change in the Home Agent
   or Correspondent Node binding. The latency involved in updating the Care
   of Address bindings at far geographical and topological distances is
   eliminated or reduced until such time as the Mobile Node is in a position
   to manage the latency cost.

   Having provided some motivation and brief summary of the underlying
   principles of LMM, it is important to enumerate goals for LMM.


   Goals for LMM:


        -   reduce the signaling induced by changes in the
            point of attachment due to the movement of a host;
            reduction in signaling delay will minimize
            packet loss and possible session loss;


        -   reduce the usage of air-interface and network
            resources for mobility;

        -   reduce the processing overhead at the peer nodes,
            thereby improving protocol scalability;


        -   avoid or minimize the changes of, or impact to the
            Mobile Node, Home Agent or the Correspondent Node;

        -   avoid creating single points of failure;

        -   simplify the network design and provisioning
            for enabling LMM capability in a network;

        -   allow progressive LMM deployment capabilities.

   Identifying a solid set of requirements that will render the
   protocol internals, for some LMM scheme, robust enough to
   cater for the aforementioned considerations becomes essential
   in designing a widely accepted solution.  The remainder of this
   document present a set of requirements that encompass essential
   considerations for the design of an LMM scheme.  It is with this
   foundation that we can seek to ensure that the resulting LMM
   solution will best preserve the fundamental philosophies and
   architectural principles of the Internet in practice today.


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2.0 Terminology

   See [2] for additional terminology.

   Administrative Domain A collection of networks under the same
                         administrative control and grouped together
                         for administrative purposes. [2]

   Local Mobility        The movement of an IP device without requiring
                         a change to its routable IP address seen by
                         the CN or HA. Although its point of attachment
                         may change during the move, the IP addresses used
                         to reach the device (both its home and globally
                         visible routable IP address) do not change.

   Local Coverage Area   A Local Coverage Area (LCA) contains one or more
   (LCA)                 IP subnets.  Within the LCA, the globally visible
                         routable IP address assigned to a Mobile Host or
                         Mobile Router serving a Mobile Network does not
                         change.

   Local Mobility Agent  A Mobile Node may use a Local Mobility Agent to
   (LMA)                 carry out the local mobility mangement
                         functionality.   The LMA functionality will reside
                         on router(s) within the Local Coverage Area.


   Localized Mobility    A method of moving an IP device without requiring
   Management (LMM)      a change to its routable IP address seen by
                         its peers, namely the MN's HA and its CNs,
                         in order to restrict the signaling area, thus
                         possibly reducing the amount of signaling.

   Strong Authentication Techniques that permit entities to provide
                         evidence that they know a particular secret
                         without revealing the secret.  [3]


3.0 LMM Requirements

   This section describes the requirements of a LMM solution.  The
   requirements are relevant to both Mobile IPv4 and Mobile IPv6.








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3.1 Intra-domain mobility

   LMM is introduced to minimize the signaling traffic to the Home Agent
   and/or Correspondent Node(s) for intra-domain mobility (within an
   Local Coverage Area).  This is the fundamental reason for
   introducing localized mobility management extensions to core Mobile
   IPv6.

   In the LMM infrastructure a Correspondent Node or Home Agent outside
   the administration domain MUST always be able to address the mobile
   host by the same IP address, so that from the point of view of hosts
   outside the administration domain, the IP address of the mobile host
   remains fixed regardless of any changes in the Mobile Node's subnet.

   It is not the intent or goal for LMM to enter the intra-subnet
   (intra AR) mobility problem space.   See [4] for more information
   on this specific problem space.

3.2 Security

3.2.1 LMM protocol MUST provide for "security provisioning" within the
      respective local coverage area.


   The security of exchanging LMM specific information and signaling MUST
   be ensured.  Security provisioning includes protecting the integrity,
   confidentiality, and authenticity of the transfer of LMM specific
   information within the administration domain.  If applicable, replay
   protection MUST exist mutually between the LMM agents.

3.2.2 LMM protocol MUST provide for the security provisioning to be
      disabled.

   In certain environments the security within the Local Coverage Area
   may not be necessary, or it may be preferred to minimize the LMM protocol
   overhead. This feature would be used at the network operator's own risk.

3.2.3 LMM protocol MUST NOT interfere with the security provisioning that
      exists between the Home Agent and the Mobile Node.

3.2.4 LMM protocol MUST NOT interfere with the security provisioning that
      exists between the Correspondent Node and the Mobile Node.

3.2.5 LMM protocol MUST NOT introduce new security holes or the possibility
      for DOS-style attacks.





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3.2.6 An LMM scheme MUST provide support for security at the
      level associated with routing.  LMM SHOULD also ensure
      that the network be able to maintain topological confidentiality
      from visiting mobile nodes.  That is to say that the LMM
      scheme in use SHOULD NOT reveal the visited network's
      topology to the Mobile Node.


3.3 Induced LMM functional requirements

3.3.1 Any Localized Mobility Management protocol MUST NOT inject
      any additional functionality over base  Mobility [6, 9] at the
      Home Agent or any of its peer CNs.  Thus, the LMM framework
      MUST NOT add any modifications or extensions to the Correspondent
      Node(s) and Home Agent. It is essential to minimize
      the involvement of the Mobile Node in routing beyond what is in
      the basic MIP and MIpv6 protocol. Preferences, load balancing, and
      other complex schemes requiring heavy mobile node involvement
      in the mobility management task SHOULD BE avoided.


3.3.2 Non-LMM-aware routers, hosts, Home Agents, and Mobile Nodes
      MUST be able to interoperate with LMM agents.


3.3.3 The LMM framework MUST NOT increase the number of messages between
      the mobile host and the respective Correspondent Node(s) and Home
      Agent.  Indeed, the LMM framework MUST minimize the global
      signaling between the MN and its peers.  The amount
      of regional signaling MUST NOT surpass the amount of global
      signaling that would have otherwise occurred if LMM were not
      present.

3.4 Scalability, Reliability, and Performance

3.4.1 The LMM complexity MUST increase at most linearly with the
      size of the local domain and the number of Mobile Nodes.


3.4.2 Any Localized Mobility Management protocol MUST assure that
      that LMM routing state scales at most linearly with the number
      of Mobile Nodes registered, and that the increase in routing
      state is confined to those ARs/ANRs involved in implementing
      the LMM protocol at hand.  This would involve MIP-specific
      routing state as binding caches in addition to standard
      routing table host routes. While host routes cannot be
      eliminated by any mobility management protocol including
      base IP mobility, any LMM protocol MUST keep the number of
      host routes to a minimum.



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3.4.3 The LMM framework MUST NOT create single points of failure in
      the network.  The current access router would be excluded from
      this requirement.

3.4.4 The LMM framework MUST NOT interfere with the basic IP mobility
      performance of a mobile host communications with a Correspondent
      Node(s).


3.4.5 Scalable expansion of the network

   The LMM framework MUST allow for scalable expansion of the network
   and provide for reasonable network configuration with regard
   to peering, inter-administrative domain connectivity,  and other
   inter-administrative domain interoperability characteristics of
   interest to wireless ISPs. The LMM framework MUST NOT introduce
   any additional restrictions in how wireless ISPs configure their
   network, nor how they interconnect with other networks beyond
   those introduced by standard IP routing.   In addition, the
   amount of regional signaling MUST NOT increase as the Local
   Domain expands in size.

3.4.6 Resilience to topological changes

   The LMM protocols MUST be topology-independent.  The LMM protocols
   MUST be able to adapt to topological changes within the domain.  The
   topological changes may include the addition or removal/failure of
   LMM agents or that of changes in the routing of the local domain
   over which the LMM scheme is applied.


3.4.7 Header or Tunneling overhead

   Any additional header or tunneling overhead caused by LMM MUST
   be reduced on the radio link by compression.  The transfer of
   compressor state on movement SHOULD be possible so as not to
   introduce any perceived service disruption.

   Candidate LMM designs that require additional header overhead for
   tunnels MUST be reviewed by the ROHC working group to determine
   if the header compressor can be restarted from transferred compressor
   context when handover occurs without requiring any full header packet
   exchange on the new link.








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3.4.8 Optimized signaling within the Local Coverage Area

   By its very nature, LMM reintroduces triangle routing into Mobile IPv6
   in that all traffic must go through the LMM agent. There is no way
   to avoid this. The LMM framework SHOULD be designed in such a way
   as to reduce the length of the unwanted triangle leg.

   The LMM design SHOULD not prohibit optimal placement of LMM agents to
   reduce or eliminate additional triangle routing introduced by LMM.

   NOTE: It is not required that a LMM scheme specify LMM agents as part
   of its solution.

3.5 Mobility Management Support

   The following LMM requirements pertain to both inter-domain and
   intra-domain hand-off.

3.5.1 The LMM framework MUST NOT increase the amount of latency or amount of
      packet loss that exists with the core Mobile IP and Mobile IPv6
      specification [6, 9].  Indeed, the LMM framework SHOULD decrease the
      amount of latency or amount of packet loss that exists with the
      core mobility protocols.

3.5.2 The LMM framework MUST NOT increase the amount of service disruption
      that already exists with the core mobility specifications.
      Again, the LMM framework SHOULD decrease the amount of service
      disruption that already exists with the core mobility protocols.


3.5.3 The LMM framework MUST NOT increase the number of messages between
      the mobile host and the respective Correspondent Node(s) and Home
      Agent as is in the core mobility specifications [6, 9].  The LMM
      framework SHOULD decrease the number of messages between the
      mobile host and the respective Correspondent Node(s) and Home
      Agent as is in the core mobility specifications [6, 9].

3.6 Auto-configuration capabilities for LMM constituents

   It is desirable that in order to allow for simple incremental
   deployment of an LMM scheme, the local mobility agents MUST
   require minimal (if any) manual configuration.  This plug-and-play
   feature could make use of IPv6 auto-configuration mechanisms in
   the case of Mobile IPv6 [6], even  though most likely other
   automatic configurations will be needed (such as, for example,
   learning about adjacent LMM agents).  Auto-configuration also
   facilitates the network to dynamically adapt to general topological
   changes (whether planned or due to link or node failures).


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3.7 LMM inter-working with IP routing infrastructure requirement

   The LMM framework MUST NOT disrupt core IP routing outside
   the local domain.


3.8 Sparse routing element population requirement

   Any LMM protocol MUST be designed to be geared towards
   incremental deployment capabilities; the latter implies
   that the LMM scheme itself imposes minimum requirements
   on the carriers network.  Incremental deployment capabilities
   for an LMM protocol signifies that an initial set of sparse
   LMM agents can populate the administration domain of a network
   provider and operate sufficiently.  In addition, any LMM
   scheme MUST be compatible with any additional deployment
   of LMM agents in future infrastructure expansions; that is to
   say, allow progressive LMM deployment capabilities.

   It is for this reason that the LMM framework MUST NOT require
   that all routing elements be assumed to be LMM-aware in the
   signaling interactions of an LMM protocol. The LMM framework
   MUST BE supported, at the very minimum, by a sparse (proper
   subset) LMM agent population that is co-located within the
   routing topology of a single administration domain.


3.9 Support for Mobile IPv4 or Mobile IPv6 Handover

   Since one of the primary goals of LMM is to minimize
   signaling during handover, an LMM solution MUST be
   available for the standardized Mobile IPv4 or Mobile IPv6
   handover algorithms.  LMM and the Mobile IP or Mobile IPv6
   handover algorithms MUST maintain compatibility in their
   signaling interactions for fulfilling complementary roles
   with respect to each other.

   This requirement SHOULD NOT be interpreted as ruling out
   useful optimizations of LMM and Mobile IP or Mobile IPv6 handoff
   schemes that simplify the implementation or deployment of LMM or
   Mobile IP or Mobile IPv6 handoff.


3.10 Simple Network design requirement

   LMM SHOULD simplify the network design and provisioning for enabling LMM
   capability in a network and allow progressive LMM deployment capabilities.


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3.12 Stability

   LMM MUST avoid any routing loops.

3.13 Quality of Service requirements

3.13.1 The LMM MUST have the ability to interwork with the
       QoS schemes to hide the mobility of the MN to its peer
       by avoiding end-to-end QoS signaling.

3.13.2 The LMM MUST have the ability to interwork with the QoS
       schemes to facilitate the new provisioning of both uplink
       and downlink QoS after a handoff.



4.0 Acknowledgments

  Thank you to all who participated in the LMM requirement discussion
  on the Mobile IP working group alias.  First, I want to recognize
  Theo Pagtzis's work on LMM requirement analysis. Theo has contributed
  significantly to the LMM discussion on the mailing list and at IETF
  working group meetings and has provided text for various requirements.
  Special thanks also to John Loughney, Alper Yegin, Alberto
  Lpez Toledo, and Madjid Nakhjiri for providing input to the
  draft in its preliminary stage and many other comments they had.
  As editor of the draft a small team was put together to work with
  me on LMM requirement analysis: Hesham Soliman, Erik Nordmark,
  Theo Pagtzis, James Kempf, and Jari Malinen.

  Many other working group members have participated in the requirement
  analysis of LMM for IPv6 on the mailing list.  Additional members who
  contributed are that are not listed above are: Charlie Perkins,
  Muhammad Jaseemuddin, Tom Weckstr, Jim Bound, Gopal Dommety,
  Glenn Morrow, Arthur Ross, Samita Chakrabarti,


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  Karim El-Malki, Phil Neumiller, Behcet Sarikaya, Karann Chew,
  Michael Thomas, Pat Calhoun, Bill Gage, Vinod Choyi, John Loughney,
  Wolfgang Schoenfeld, and David Martin.
  Recent comments received by Atsushi Takeshita, Daichi Funato,
  Youngjune Gwon,  Ichiro Okajima, Jari Malinen, Kacheong Poon, and
  Koshimi Takashi.  Thanks to Cedric Westphal for a thorough reviewing
  of the draft.

  An academic analysis of this body of work was completed by a number
  of members of the Mobile IP working group and published in [1] below.

  In addition special thanks to the Mobile IP working group chairs
  for their input as well as capturing/organizing the initial set of
  requirements from the discussions, Phil Roberts and Basavaraj Patil.


5.0 References

   [1]            T. Pagtzis, C. Williams, P. Kirstein, C. Perkins  and
                  A. Yegin, "Requirements for Localised IP Mobility
                  Management", Proceedings of IEEE Wireless Communications
                  and Networking Conference (WCNC2003), Louisiana,
                  New Orleans, March 2003

   [2]            Manner, J. et al; "Mobility Related Terminology";
                  draft-manner-seamoby-terms-02.txt; Work IP; July 2001.

   [3]            J.J. Tardo and K. Alagappan, "SPX: Global Authentication
                  Using Public Key Certificates." In Proc IEEE Symp.
                  Research in Security and Privacy.  IEEE CS Press, 1991.

   [4]            Roberts, P., "Local Subnet Mobility Problem Statement";
                  draft-proberts-local-subnet-mobility-problem-01.txt;
                  Work In Progress; May 2001.

   [5]            Perkins, C., "IP Mobility Support for IPv4,"
                  RFC3220, January 2002.

   [6]            David B. Johnson, Charles Perkins, J. Arkko,
                  "Mobility Support in IPv6";
                  draft-ietf-mobileip-ipv6-21.txt; February 2003.

   [7]            R. Koodli. (Editor), "Fast Handovers for Mobile
                  IPv6"; draft-ietf-mobileip-fast-mipv6-05.txt; a work
                  in progress; September 2002.

   [8]            Loughney, J. (Editor), "SeaMoby Micro Mobility Problem
                  Statement"; draft-ietf-seamoby-mm-problem-01.txt; a work
                  in progress; February 2001.


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6.0 Authors' Addresses

   The working group can be contacted via the current chairs:

   Basavaraj Patil               Phil Roberts
   Nokia Corporation             Megisto Systems
   6000 Connection Drive         20251 Century Blvd
   Irving, TX 75039              Suite 120
   USA                           Germantown Maryland, 20874-1191

   Phone:  +1 972-894-6709       EMail:  proberts@megisto.com
   EMail:  Raj.Patil@nokia.com
   Fax :  +1 972-894-5349

Questions about this memo can also be directed to:

        Carl Williams
        MCSR Labs
        3790 El Camino Real
        Palo ALto, CA 94306
        USA
        phone: +1 650 279 5903
        fax:   +1 650 328 3381
        email: carlw@mcsr-labs.org

7.0 Full Copyright Statement

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph
   are included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.
   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

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