DMM Working Group                                             M. Liebsch
Internet-Draft                                                       NEC
Intended status: Standards Track                                P. Seite
Expires: August 18, 2014                           Orange-France Telecom
                                                          G. Karagiannis
                                                    University of Twente
                                                           S. Gundavelli
                                                                   Cisco
                                                       February 14, 2014


         Distributed Mobility Management - Framework & Analysis
              draft-liebsch-dmm-framework-analysis-03.txt

Abstract

   Mobile operators consider the distribution of mobility anchors to
   enable offloading some traffic from their core network.  The
   Distributed Mobility Management (DMM) Working Group is investigating
   the impact of decentralized mobility management to existing protocol
   solutions, while taking into account well defined requirements, which
   are to be met by a future solution.  This document discusses DMM
   using a functional framework.  Functional Entities to support DMM as
   well as reference points between these Functional Entities are
   introduced and described.  The described functional framework allows
   distribution and co-location of Functional Entities and build a DMM
   architecture that matches the architecture of available protocols.
   Such methodology eases the analysis of best current practices with
   regard to functional and protocol gaps.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on August 18, 2014.

Copyright Notice



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   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Conventions and Terminology  . . . . . . . . . . . . . . . . .  5
   3.  Functional Architecture for DMM Support  . . . . . . . . . . .  6
   4.  Different Constellations of Functional Entities  . . . . . . . 11
     4.1.  Condensed Deployment: Mobility Protocol Centric
           Solutions  . . . . . . . . . . . . . . . . . . . . . . . . 11
     4.2.  Cooperative Deployment: Distributed Architecture . . . . . 12
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 14
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 15
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 16
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 16
   Appendix A.  How the framework can support a gap analysis!
                Some examples.. . . . . . . . . . . . . . . . . . . . 17
     A.1.  Condensed Deployment using Mobile IPv6 . . . . . . . . . . 17
     A.2.  Condensed Deployment using Proxy Mobile IPv6 . . . . . . . 17
     A.3.  Cooperative Deployment using LISP  . . . . . . . . . . . . 17
     A.4.  Cooperative Deployment using iBGP  . . . . . . . . . . . . 18
   Appendix B.  Functional Architecture for Multicast DMM Support . . 21
   Appendix C.  Change Notes  . . . . . . . . . . . . . . . . . . . . 25
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26














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1.  Introduction

   The concept of Distributed Mobility Management (DMM) is based on the
   distribution of mobility anchors towards the access networks to
   provide mobile nodes with local anchors and enable optimized routing
   of traffic above anchor level to any kind of serving point, e.g.
   distributed content caches.  The closer mobility anchors are located
   to mobile nodes, the more a mobile node's handover may necessitate
   the assignment of a new mobility anchor.  Continuity of a mobile
   node's IP address or IP address prefix enables IP session continuity,
   but creates the problem of routing downlink packets to the mobile
   node's current mobility anchor.  Different solutions and associated
   extensions to IP mobility management protocols are being discussed to
   maintain a mobile node's IP session after mobility anchor relocation,
   including solutions that are based on existing protocols.

   This document defines a functional framework for DMM and describes an
   initial set of well defined functional entities (FE), which are
   required to support IP address continuity in a network with
   distributed mobility anchors.  Having identified the function of each
   FE as well as required interfaces between FEs allows different
   constellations of FEs, either by co-locating or distributing them.
   Functional frameworks have been successfully used within and outside
   of the IETF, such as the ITU-T [ITU-TY2018][ITU-TY2804], to support
   the thorough analysis of protocols gaps with existing protocols and
   to enable the design of suitable solutions.  Due to the complexity of
   the DMM problem and solutions space, we consider such framework of
   particular importance for performing a Gap Analysis while assigning
   the defined FEs to architecture components of existing protocols and
   to build suitable solutions for DMM based on extensions to a single
   or multiple existing protocols and architecture components.

   This version of the draft introduces a basic set of FEs and
   interfaces between these FEs to support IP address continuity in DMM,
   without being specific to the used mobility management protocol,
   which operates below the mobility anchor.  The functional framework
   as per this draft is protocol agnostic, such that it can apply to (1)
   solutions that are solely based on existing IP mobility protocols and
   to (2) solutions which get support from non-mobility protocols.

   The framework enables the analysis of existing protocols' suitability
   to support DMM and allows building optimized solutions for DMM
   without being limited to the mobility protocol suites.  In
   particular, the framework can be used to build solutions on the
   following challenges that are currently being discussed in the
   context of DMM rechartering:





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   o  Support of different deployment models, where the mobility anchors
      can be located in the access networks or in the core/backbone
      network

   o  Anchor selection mechanisms

   o  Control- and Data-plane separation techniques for mobility
      components

   o  Enhancements to mobile node for operating in a DMM-enabled network

   o  Policy extensions for supporting DMM

   o  Optimized traffic steering approaches for DMM used to ensure IP
      address continuity

   o  Exposing mobility states (incl. binding state, access network
      parameters, etc.) to inter-work, for example, with SDN technology

   Some examples how the framework can support the identification of
   required protocol extensions to existing mobility management protocol
   or alternatively the support from non-mobility protocols to design
   suitable DMM solutions on system level are described in Appendix A.

   Appendix B defines an additional set of functional entities, which
   enables multicast support in DMM and can complement the framework for
   DMM unicast support.
























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2.  Conventions and Terminology

   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 [RFC2119].














































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3.  Functional Architecture for DMM Support

   The framework introduces four additional functional entities (FE)
   which are relevant complement existing mobility- and transport
   networks to enable DMM support for unicast traffic and to meet
   essential DMM requirements as per [I-D.ietf-dmm-requirements], such
   as enabling temporary IP address continuity after a mobile node got
   assigned a new mobility anchor.  Further FEs may be needed to enable
   advanced features, such as simultaneous use of an imported mobile
   node HoA or HNP to maintain ongoing data sessions and a new HoA or
   HNP, which is allocated by the mobile node's new mobility anchor
   after handover.  Additional FEs are not considered in this revision
   of the draft, but can be introduced easily in future versions of the
   draft and considered for the BCP discussion and gap analysis.

   The following FEs are currently considered as existing functional
   entities to build the mobility- and transport network:

   o  FE_R: Functional Entity of a standard IP Router / Switch

   o  FE_MA_C: Functional Entity Mobility Anchor, Control Plane

   o  FE_MA_U: Functional Entity Mobility Anchor, User Plane

   o  FE_MU_C: Functional Entity Mobile User Client, Control Plane

   o  FE_MU_U: Functional Entity Mobile User Client, User Plane

   The list comprises a generic router/switch function FE_R that's
   supposed to build the transport network.  It has no particular
   function that's specific to DMM, but performs routing according to a
   longest prefix match.  Deployment specific aspects, such as the use
   of IP/MPLS, are not (yet) considered in this draft.

   The entities FE_MA_C and FE_MA_U represent the unmodified functions
   of the mobility architecture's mobility anchor.  In Mobile IPv6,
   these function would be co-located with the Home Agent, in Proxy
   Mobile IPv6, these functions would be co-located with the Local
   Mobility Anchor (LMA).  In a cellular IP (CIP) enabled domain, these
   functions would be co-located with the domain's CIP Gateway.

   The entities FE_MU_C and FE_MU_U represent the existing user client
   functions, that send location updates to the mobility anchor.  In
   Mobile IPv6, these functions are co-located with the Mobile Node,
   whereas in Proxy Mobile IPv6, these functions are co-located with the
   Mobile Access Gateway.

   So far, this draft defines four DMM-specific FEs, which can be either



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   distributed or co-located with existing FEs of the mobility- or
   routing plane.  One or more of the following FEs are currently
   assumed to add to an existing mobility- and transport network to
   enable DMM support for IP address continuity:

   o  FE_MCTX: Functional Entity Mobility Context Transfer

   o  FE_I: Functional Entity Ingress to DMM plane

   o  FE_E: Functional Entity Egress of DMM plane

   o  FE_IEC: Functional Entity for Ingress/Egress Control

   Note: No all FEs or reference points between FEs may be relevant for
   a DMM-enabled solution that is based on existing protocols and the
   associated architecture.  Which functions are relevant to complement
   an existing protocol and architecture depends on the identified gaps.

   The task of the FE_MCTX is to export relevant binding cache
   information, such as the mobile node's HoA or HNP, from the mobile
   node's previous mobility anchor (pMA) during mobility anchor
   relocation to enable IP address continuity after mobility anchor
   relocation.  Furthermore, the function allows importing mobility
   context on the mobile node's new mobility anchor.  Imported HoA/HNP
   of a mobile node will be treated as identifier and non-routable IP
   address (prefix), as it probably does not match the new mobility
   anchor's location in the topology.  Furthermore, the FE_MCTX can
   provide mobility context to the FE_IEC to allow keeping these
   policies updated, which allow forwarding of packets to the MN's
   currently used mobility anchor.

   The function FE_I enables the ingress level of indirection by means
   of deviating from the standard routing path of the mobile node's
   downlink packets, which carry the mobile node's HoA/HNP in the
   destination IP address field of their IP header.  The FE_I can
   retrieve information from a control function (FE_IEC) to establish
   forwarding of the mobile node's packets to the appropriate DMM egress
   function (FE_E).  Forwarding can be for example accomplished by an IP
   tunnel to the egress function, address translation to a routable IP
   address or other means.

   The function FE_E receives downlink packets being forwarded by the
   DMM ingress function FE_I, e.g. by terminating a forwarding tunnel.
   The state on the FE_I can be established through the DMM ingress/
   egress control function (FE_IEC) and is used to identify an MN's
   received packets and deliver them to the MN's current mobility anchor
   (FE_MA).  If the FE_E is co-located with the FE_MA, the delivery is a
   local operation.  If the FE_E is not co-located with the FE_MA, other



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   techniques, such as host-routes or technology such as OpenFlow may be
   used to deliver the packets to the mobile node's current mobility
   anchor.  If not co-located with the FE_MA, the FE_E is supposed to be
   located close to the mobile node's current FE_MA.

   The function FE_IEC represents a control function, that establishes,
   updates and removes policies (per-host or grouped) in the FE_I and
   the FE_E to allow forwarding of a mobile node's downlink packets
   towards the mobile node's current mobility anchor.

   The mobile node's IP address (prefix) is carried in the source
   address field of the uplink packet.  This source address is thus
   topologically incorrect after mobile node's handover.  When IP
   routers of the mobility domain do not apply filtering according to
   the source addresses, uplink packets can be assumed to be routable
   and no specific operation is required.

   If source address filtering is used, relevant routers need to be
   reconfigured to exclude the mobile node's IP address from filtering
   rules.  If such filtering is performed by a mobility anchor or a
   Proxy Mobile IPv6 Mobile Access Gateway (MAG), local mobility
   functions on these routers should perform the task to reconfigure the
   local filter rules for uplink traffic.

   When traffic indirection also applies to the uplink, e.g. to enable
   bidirectional tunneling to ensure that downlink and uplink data
   packets always traverse the same ingress/egress functions, FE_E and
   FE_I functions come into play on the uplink path.  Downlink FE_I and
   FE_E become respectively FE_E and FE_I on the uplink.  The uplink
   FE_I forwards a mobile node's packets to the FE_E corresponding to
   the downlink FE_I that has sent packets with the mobile node's
   address in the destination address field.  The FE_I can also retrieve
   the information from the FE_IEC.

   Figure 1 illustrates how the four DMM-specific FEs complement
   existing FEs of the mobility architecture.  These DMM-specific FEs
   and associated operation on the interfaces between them can be
   realized by existing protocols, extensions to them or new protocols.
   Figure 1 separates the data plane from the control plane.












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                Control Plane:        :        Data Plane:
                                      :
                                      :         |data packet
                                      :         v for mobile node
              +----+      R_IC        :      +----+
              |FE_I|<----------+      :      |FE_I|
              +----+           |      :      +----+
                          +--+ |      :         |
                      R_II|  | |      :         |
                          v  v v      :         |
                         +------+     :         |
                         |FE_IEC|     :         |
                         +------+     :         |
                           ^  ^       :         v
              +----+       |  |       :      +----+
              |FE_E|<------+  |R_XC   :      |FE_E|
              +----+  R_EC    |       :      +----+
                              v       :         |
                           +-------+  :         |
                           |FE_MCTX|  :         |
                           +-------+  :         |
                            ^^ ^  ^   :         v
            +-------+       || |  |   :     +-------+
            |FE_MA_C|<------+| +--+   :     |FE_MA_U|
            +-------+  R_XA  | R_XX   :     +-------+
                             |        :         |
                             |        :         v
            +-------+        |        :     +-------+
            |FE_MU_C|<-------+        :     |FE_MU_U|
            +-------+  R_XU           :     +-------+
                                      :


     Figure 1: Basic set of functional entities (FE) and interfaces to
                    enable IP-address continuity in DMM

   The reference points between FEs comprise the following features:

   o  R_XA: Enables the FE_MCTX to retrieve mobility context information
      from the FE_MA of the MN's mobility anchor.  Such information
      includes for example the MN's Home Address (HoA) or Home Network
      Prefix (HNP).  In the network of the MN's new mobility anchor, the
      reference point enables the FE_MCTX to provide the MN's mobility
      context to the associated FE_MA, that imports the MN's mobility
      context to enable IP address continuity.

   o  R_XU: Enables the FE_MCTX to retrieve mobility context information
      from the mobile user client control function, the FE_MU_C. In host



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      mobility management, this function is located on the Mobile Node,
      who could support DMM operation by notifying the FE_MCTX through
      this reference point.

   o  R_XX: Enables the direct transfer of an MN's mobility context
      between two functions FE_MCTX, which are typically located in the
      network of the MN's previous and new mobility anchor respectively.

   o  R_IC: Enables the FE_IEC to provide policies to the FE_I, which
      are used to forward the MN's downlink packets towards the MN's new
      mobility anchor and the associated FE_E. These policies can be
      provided to the FE_I in an unsolicited manner or on request by the
      FE_I.

   o  R_EC: Enables the FE_IEC to provide policies to the FE_E, which
      are used at the FE_E to identify received packets that belong to a
      particular MN and deliver these packets to the MN's new mobility
      anchor.  Such policies could include, for example, tunnel endpoint
      information, flow identification rules or other identification and
      addressing rules.

   o  R_XC: Enables initialization and update of the FE_IEC about the
      MN's mobility context as well as about its current location as
      represented by the FE_E in the network of the MN's current
      mobility anchor.

   o  R_II: Multiple instances of an FE_IEC can be deployed to build a
      DMM architecture, e.g. to distribute load and scale better, or
      distribute tasks associated with the FE_IEC to enable cooperative
      solutions.





















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4.  Different Constellations of Functional Entities

   The defined FEs can be grouped or distributed to build a DMM
   architecture that considers new architecture components or that is
   based on components of existing protocols.  As a starting point, this
   section depicts and describes two deployment variants, which reflect
   the current understanding of the WG how DMM could be accomplished
   using existing protocol specifications as base.  Variants of these
   two deployment models or entirely new models are possible and can be
   added to future versions of this document.

   Note: This section is incomplete and needs further input on different
   deployment models and variants.

4.1.  Condensed Deployment: Mobility Protocol Centric Solutions

   Mobility protocol centric solutions aim at extensions to available
   mobility protocols to enable DMM, without being dependent on any
   external, non-mobility component and protocol.  IP address continuity
   is typically established on the control plane by extensions to the
   mobility protocol to convey an MN's mobility context to a new
   mobility anchor, and on the data plane by the establishment of a
   forwarding tunnel between mobility anchors to deliver downlink
   packets from the originally assigned mobility anchor to the MN's
   currently used mobility anchor after anchor relocation.
   Alternatively, IP address continuity is enabled by using multiple
   mobility anchors simultaneously, whereas the mobile node's IP
   address(es) remain anchored at the topologically correct anchor
   point.  These approaches differ in the level of extensions to the
   mobility protocols and in the support of certain features on the
   mobile node, such as the simultaneous use of multiple mobility
   anchors and associated Home Addresses.  They have in common the sub-
   optimal routing path, as the mobile node's downlink traffic needs to
   traverse the location of the IP addresses topologically correct
   mobility anchor.
















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               |data destined
               v to mobile node (MN)
             +----+
             |FE_R|
             +----+
               |
               |
               |
               |
               |
               |
           +---v--------------+                 +------------------+
           | +----+           |                 | +----+           |
           | |FE_I|--==========================-->|FE_E|           |
           | +----+           |                 | +----+           |
           |        +------+  |                 |   |    +------+  |
           |        |FE_IEC|  |                 |   |    |FE_IEC|  |
           |        +------+  |                 |   |    +------+  |
           |                  |                 |   |              |
           |        +-------+ |                 |   |    +-------+ |
           |        |FE_MCTX| |                 |   |    |FE_MCTX| |
           |        +-------+ |                 |   v    +-------+ |
           |+-------++-------+|                 |+-------++-------+|
           ||FE_MA_C||FE_MA_U||                 ||FE_MA_U||FE_MA_C||
           |+-------++-------+|                 |+-------++-------+|
           +------------------+                 +---|--------------+
             MN's previous MA                       |  MN's current MA
                                                    v
                                                   +--+
                                                   |MN|
                                                   +--+

    Figure 2: Condensed Deployment: Mobility Protocol Centric Solutions

4.2.  Cooperative Deployment: Distributed Architecture

   A distributed architecture considers protocol operation between
   distributed FEs, aiming at a DMM solution that's to a large extent
   independent of the mobility architecture and protocol.  A further
   goal is to establish optimal routing paths for the MN's traffic after
   the MN's mobility anchor has been relocated and IP address continuity
   must be provided.









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                  |data destined
                  v to mobile node (MN)
                +----+
                |FE_R|
                +----+
                  |
                  v
                +----+
                |FE_I|----------------------------------------+
                +----+                                        |
                                    +------+                  |
                                    |FE_IEC|                  |
                                    +------+                  |
                                                              |
              +------------------+             +--------------v----+
              |        +-------+ |             | +-------+  +----+ |
              |        |FE_MCTX| |             | |FE_MCTX|  |FE_E| |
              |        +-------+ |             | +-------+  +----+ |
              |+-------++-------+|             |              |    |
              ||FE_MA_C||FE_MA_U||             |+-------+ +-------+|
              |+-------++-------+|             ||FE_MA_C| |FE_MA_U||
              +------------------+             |+-------+ +-------+|
                  MN's previous                +--------------|----+
                  mobility                      MN's current  v
                  anchor                        mobility    +--+
                                                anchor      |MN|
                                                            +--+

        Figure 3: Cooperative Deployment: Distributed Architecture






















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5.  Security Considerations

   Different constellations of Functional Entities may allow re-use of
   existing protocols' security mechanisms to protect DMM protocol
   operation.  In particular in a distributed model, new interfaces must
   be protected, e.g. to counteract unauthorized packet redirection to a
   different, possibly malicious mobility anchor.  Details about
   security threats will be studied when the placement of Functional
   Entities for a selected set of preferred deployment models becomes
   mature.









































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6.  IANA Considerations

   As this document represents a framework and no protocol
   specification, there is no need for IANA actions.















































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7.  References

7.1.  Normative References

   [I-D.ietf-dmm-requirements]
              Chan, A., Liu, D., Seite, P., Yokota, H., and J. Korhonen,
              "Requirements for Distributed Mobility Management",
              draft-ietf-dmm-requirements-14 (work in progress),
              February 2014.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4601]  Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
              "Protocol Independent Multicast - Sparse Mode (PIM-SM):
              Protocol Specification (Revised)", RFC 4601, August 2006.

   [RFC4605]  Fenner, B., He, H., Haberman, B., and H. Sandick,
              "Internet Group Management Protocol (IGMP) / Multicast
              Listener Discovery (MLD)-Based Multicast Forwarding
              ("IGMP/MLD Proxying")", RFC 4605, August 2006.

   [RFC6224]  Schmidt, T., Waehlisch, M., and S. Krishnan, "Base
              Deployment for Multicast Listener Support in Proxy Mobile
              IPv6 (PMIPv6) Domains", RFC 6224, April 2011.

7.2.  Informative References

   [ITU-TY2018]
              "ITU-T Y.2018, Mobility management and control framework
              and architecture within the NGN transport stratum".

   [ITU-TY2804]
              "ITU-T Q.1707/Y.2804, Generic framework of mobility
              management for next generation networks".
















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Appendix A.  How the framework can support a gap analysis! Some
             examples..

   A Gap analysis can be performed according to different deployment
   models and variants as summarized in Section 4.  A suitable set of
   DMM FEs can be mapped to the architecture of existing protocols from
   within or beyond the IP mobility protocol solution space to analyze
   and identify gaps in the chosen protocols to support and optimize DMM
   operations.  This section provides a few examples about the mapping
   of DMM FEs to mobility protocol FEs and non-mobility protocol FEs.
   Common goal is to enable DMM support, either in a mobility protocol
   centric manner or by means of a distributed architecture, relying on
   the support and associated collaboration with non-mobility protocol
   functions, such as routing.  As examples for the distributed
   architecture, the Locator-Identifier Split Protocol (LISP) and the
   iBGP have been used to enable traffic indirection in the routing
   plane above the topological level of distributed mobility anchors.

A.1.  Condensed Deployment using Mobile IPv6

   Note: A detailed example needs to be added in a next revision.

   Description: Framework mapping to existing Mobile IPv6 architecture.
   Technical approach is the establishment of a forwarding tunnel
   between previous HA and new HA to enable IP address continuity after
   anchor relocation.  Approach is the identification of missing
   protocol functions in Mobile IPv6 as expected from DMM functional
   entities as per this specification to enable full DMM support.

A.2.  Condensed Deployment using Proxy Mobile IPv6

   Note: A detailed example needs to be added in a next revision.

   Description: Framework mapping to existing Proxy Mobile IPv6
   architecture.  Technical approach is the establishment of a
   forwarding tunnel between previous LMA and new LMA to enable IP
   address continuity after anchor relocation.  Approach is the
   identification of missing protocol functions in Proxy Mobile IPv6 as
   expected from DMM functional entities as per this specification to
   enable full DMM support.

A.3.  Cooperative Deployment using LISP

   This example utilizes LISP Tunnel Ingress Routers (TIR) to perform
   the LISP map and encap procedure and tunnel packets to the mobile
   node's current mobility anchor (Figure 4).  The mobile node's IP
   address is assumed routable above TIR level.  TIRs can be for example
   deployed close to a mobile operator's IXP or close to operator-owned



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   traffic sources, such as a mobile Content Delivery Network (CDN).  A
   TIR, which receives data packets destined to the mobile node, can
   consult the LISP Mapping Database (DB) to resolve the mobile node's
   IP address into its current locator, which is the mobile node's
   currently used mobility anchor.  The mobility anchor has to terminate
   the LISP tunnel at the Tunnel Egress Router (TER) function and
   forward the data packets to the mobile node's current location
   according to the utilized mobility management protocol.  An
   identified gap in a setup with LISP is the dynamic update of the
   Mapping Database and the update of already established states in TIRs
   in case the mobile node's location has changed from one mobility
   anchor to another mobility anchor.



                  |data destined
                  v to mobile node (MN)
                +----+
                |TIR/|         encapsulated traffic
                |FE_I|-=======================================++
                +----+             +----------+               ||
                      \   map      |Mapping DB|               ||
                       +---------->|  FE_IEC  |               ||
                           +------>+----------+               ||
           Update Map Entry|                                  ||
              +------------|-----+             +--------------||---+
              |        +-------+ |     CTX     | +-------+  +---+  |
              |        |FE_MCTX|---------------->|FE_MCTX|->|TER|  |
              |        +-------+ |             | +-------+  +---+  |
              |+-------++-------+|             |              |    |
              ||FE_MA_C||FE_MA_U||             |+-------+ +-------+|
              |+-------++-------+|             ||FE_MA_C| |FE_MA_U||
              +------------------+             |+-------+ +-------+|
                  MN's previous                +--------------|----+
                  mobility                      MN's current  v
                  anchor                        mobility    +--+
                                                anchor      |MN|
                                                            +--+

              Figure 4: Example: DMM indirection at LISP TIRs

A.4.  Cooperative Deployment using iBGP

   This example utilizes the iBGP to establish per-host or group states
   in iBGP routers and forward a mobile node's packets hop-by-hop to its
   currently used mobility anchor.  Figure 5 depicts an iBGP router with
   co-located FE_E and FE_I to receive data packets and to forward these
   packets to the next hop according to the routing state as per iBGP



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   update.  The FE_IEC can be represented by the iBGP component to
   enable the setup of distributed routing states in distributed iBGP
   routers to direct the mobile node's data packets to its current
   mobility anchor.  Hence, the FE_IEC is distributed in all iBGP
   routers to collaborate in the setup of host routes.  The mobility
   anchor itself must implement iBGP to contribute to the distribution
   and update of host routes, e.g. after the mobile node changed its
   mobility anchor while IP address continuity must be supported.  Since
   iBGP has been designed to propagate routing states to distributed
   routers, only minor protocol gaps may be identified in a detailed
   analysis.  Beyond protocol gaps, further aspects need to be analyzed
   in such setup, which include limitations in scalability and route
   update latency.






































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               iBGP Router (RTR) with DMM FEs:
                             +--------------------+
                             |+----+        +----+|
        incoming data ------->|FE_E|------->|FE_I|--------->
                             |+----++------++----+| Forward data
                             |      |FE_IEC|      | to Next Hop
                             |      +------+      |
                             |          +         |
                             +----------+---------+
                                        +
                                        V iBGP protocol operation


                  |
                  |data destined
                  v to mobile node (MN)
                +----+                    +----+
                |iBGP|------------------->|iBGP|---------------+
                |RTR |                    |RTR |               |
                +----+ <++++++iBGP+++++++>+----+               |
                   ^                        ^                  |
                   +         +----+         +                  |
                   +++iBGP++>|iBGP|<++iBGP++++++++++++++++++++ |
                             |RTR |                          + |
                             +----+                          + |
                                                             + |
                                                             + |
                                                             + |
              +------------------+             +-------------v-V---+
              |        +-------+ |     CTX     | +-------+  +----+ |
              |        |FE_MCTX|---------------->|FE_MCTX|->|iBGP| |
              |        +-------+ |             | +-------+  |RTR | |
              |                  |             |            +----+ |
              |+-------++-------+|             |              |    |
              ||FE_MA_C||FE_MA_U||             |+-------+ +-------+|
              |+-------++-------+|             ||FE_MA_C| |FE_MA_U||
              +------------------+             |+-------+ +-------+|
                  MN's previous                +--------------|----+
                  mobility                      MN's current  v
                  anchor                        mobility    +--+
                                                anchor      |MN|
                                                            +--+

            Figure 5: Example: DMM indirection at iBGP routers







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Appendix B.  Functional Architecture for Multicast DMM Support

   The framework for multicast DMM support is similar to the framework
   for unicast DMM support introduced in Section 3 with the main
   difference that the additional introduced features are needed to
   support the multicast control and user plane.  This framework,
   similar to the one introduced in Section 3, introduces four DMM-
   specific, with the main difference that these FEs are able to support
   multicast traffic, instead of unicast traffic.  Additional FEs might
   be needed but are not considered in this revision of the draft, but
   can be introduced easily in future versions of the draft and
   considered for the BCP discussion and gap analysis.

   The following FEs are currently considered as existing multicast
   based Functional entities to build the mobility- and transport
   network:

   o  FE_MR: Functional Entity of a standard Multicast IP Router /
      Switch.  This FE can be incorporated to support the functionality
      of a Rendezvous Point (RP) and of a Designated Router (DR), see
      e.g., [RFC4601].

   o  FE_MLD-P: Functional Entity of a standard Multicast Listener
      Discovery Proxy (MLSD-P) used to provide MLD based forwarding,
      following the operation defined in e.g., [RFC4605] and [RFC6224].

   o  FE_MA_C_M: Functional Entity Mobility Anchor, Control Plane, for
      the support of multicast traffic

   o  FE_MA_U_M: Functional Entity Mobility Anchor, User Plane, for the
      support of multicast traffic

   o  FE_MU_C: Functional Entity Mobile User Client, Control Plane, for
      the support of unicast and multicast traffic.  In case of
      multicast traffic the FE_MU_C can operate as multicast sender and
      multicast listener.

   o  FE_MU_U: Functional Entity Mobile User Client, User Plane, for the
      support of unicast and multicast traffic.  In case of multicast
      traffic the FE_MU_U can operate as multicast sender and multicast
      listener.

   The four DMM-specific FEs used to support multicast traffic are
   listed below.

   o  FE_MCTX_M: Functional Entity Mobility Context Transfer, used for
      the support of multicast traffic.




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   o  FE_I_M: Functional Entity Ingress to DMM plane, used for the
      support of multicast traffic.

   o  FE_E_M: Functional Entity Egress of DMM plane, used for the
      support of multicast traffic.

   o  FE_IEC_M: Functional Entity for Ingress/Egress Control, used for
      the support of multicast traffic.

   These FEs support similar features as the ones supported by the
   FE_MCTX, FE_I, FE_E, FE_IEC FEs, respectively, described in
   Section 3, with the main difference that they are used for the
   support of the multicast control and user planes, instead of the
   unicast control and user planes.

   Figure 6 depicts the basic set of functional entities (FE) and
   interfaces to enable IP-address continuity in multicast based DMM.
   The four DMM-specific FEs and their associated operation on the
   interfaces between them can be realized by existing protocols,
   extensions to them or new protocols.































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                 Control Plane:        :        Data Plane:
                                       :
                                       :         |data packet
                                       :         v for mobile node
             +------+      R_IC_M      :      +------+
             |FE_I_M|<----------+      :      |FE_I_M|
             +------+           |      :      +------+
                           +--+ |      :         |
                     R_II_M|  | |      :         |
                           v  v v      :         |
                        +--------+     :         |
                        |FE_IEC_M|     :         |
                        +--------+     :         |
                            ^  ^       :         v
             +------+       |  |       :      +------+
             |FE_E_M|<------+  |R_XC_M :      |FE_E_M|
             +------+ R_EC_M   |       :      +------+
                               v       :         |
                      +-------------+  :         |
                      |FE_MCTX_M    |  :         |
                      +-------------+  :         |
                        ^ ^  ^^ ^  ^   :         |
          +------+      | |  || |  |   :         |
          |FE_MR |<-----  |  || |  |   :         |
          +------+ R_XH_M |  || |  |   :         |
                          |  || |  |   :         |
          +---------+     |  || |  |   :         |
          |FE_MLD-P |<----   || |  |   :         |
          +---------+ R_XD_M || |  |   :         |
                             || |  |   :         v
           +---------+       || |  |   :     +------------------------+
           |FE_MA_C_M|<------+| +--+   :     |FE_MA_U_M/FE_MR/FE_MLD-P|
           +---------+ R_XA_M | R_XX_M :     +------------------------+
                              |        :         |
                              |        :         v
             +-------+        |        :     +-------+
             |FE_MU_C|<-------+        :     |FE_MU_U|
             +-------+  R_XU_M         :     +-------+

     Figure 6: Basic set of functional entities (FE) and interfaces to
            enable IP-address continuity in multicast based DMM

   The reference points between FEs are shown in Figure 6.  In
   particular the features comprised by the reference points R_XA_M,
   R_XU_M, R_XX_M, R_IC_M, R_EC_M, R_XC_M, R_II_M, are similar to the
   ones supported by the reference points R_XA, R_XU, R_XX, R_IC, R_EC,
   R_XC, R_II, respectively, described in Section 3, with the difference
   that they are used to support the multicast based control plane,



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   instead of supporting the unicast based control plane.

   Two additional reference points are added that are comprising the
   following features:

   o  R_XH_M: Enables the FE_MCTX_M to retrieve MR routing based
      information from FE_MR following the operation defined in e.g.,
      [RFC4601].

   o  R_XD_M: Enables the FE_MCTX_M to retrieve Multicast Listener
      Discovery forwarding information from FE_MLD-P following the
      operation defined in e.g., [RFC4605] and [RFC6224].







































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Appendix C.  Change Notes

   Changes in version 01:

   o  Introduced functional split between existing Mobility Anchor
      Control- and User-Plane

   o  Introduced functional split of existing mobile user client
      Control- and User-Plane

   o  Added uplink routing considerations in DMM architecture

   o  Description of a first DMM Multicast framework in the Appendix

   o  Added examples to the appendix about how to use the framework for
      a gap analysis and for the design of optimized DMM solutions



































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Authors' Addresses

   Marco Liebsch
   NEC Laboratories Europe
   NEC Europe Ltd.
   Kurfuersten-Anlage 36
   D-69115 Heidelberg,
   Germany

   Phone: +49 6221 4342146
   Email: liebsch@neclab.eu


   Pierrick Seite
   Orange-France Telecom
   4, rue du Clos Courtel, BP 91226
   Cesson-Sevigne,   35512
   France

   Phone:
   Email: pierrick.seite@orange-ftgroup.com


   Georgios Karagiannis
   University of Twente
   AE Enschede,   7500
   Netherlands

   Phone: +31 53 4894099
   Email: karagian@cs.utwente.nl


   Sri Gundavelli
   Cisco
   170 West Tasman Drive
   San Jose, CA  95134
   USA

   Email: sgundave@cisco.com












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