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Versions: 00 draft-ietf-dmm-deployment-models

DMM WG                                                     S. Gundavelli
Internet-Draft                                                     Cisco
Intended status: Informational                             April 3, 2016
Expires: October 5, 2016


         DMM Deployment Models and Architectural Considerations
                 draft-wt-dmm-deployment-models-00.txt

Abstract

   This document identifies the deployment models for Distributed
   Mobility Management architecture.

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
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   This Internet-Draft will expire on October 5, 2016.

Copyright Notice

   Copyright (c) 2016 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
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   (http://trustee.ietf.org/license-info) in effect on the date of
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   described in the Simplified BSD License.






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Table of Contents

   1.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Conventions and Terminology  . . . . . . . . . . . . . . . . .  3
     2.1.  Conventions  . . . . . . . . . . . . . . . . . . . . . . .  3
     2.2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  DMM Architectural Overview . . . . . . . . . . . . . . . . . .  4
     3.1.  DMM Service Primitives . . . . . . . . . . . . . . . . . .  4
     3.2.  DMM Functions and Interfaces . . . . . . . . . . . . . . .  5
       3.2.1.  Home Control-Plane Anchor (H-CPA): . . . . . . . . . .  5
       3.2.2.  Home Data-Plane Anchor (H-DPA):  . . . . . . . . . . .  6
       3.2.3.  Access Control Plane Node (Access-CPN) . . . . . . . .  6
       3.2.4.  Access Data Plane Node (Access-DPN)  . . . . . . . . .  6
       3.2.5.  DMM Function Mapping to other Architectures  . . . . .  6
   4.  Deployment Models  . . . . . . . . . . . . . . . . . . . . . .  7
     4.1.  Model-1: Split Home Anchor Mode  . . . . . . . . . . . . .  7
     4.2.  Model-2: Seperated Control and User Plane Mode . . . . . .  8
     4.3.  Model-3: Centralized Control Plane Mode  . . . . . . . . .  9
     4.4.  Model-4: Data Plane Abstraction Mode . . . . . . . . . . . 10
     4.5.  On-Demand Control Plane Orchestration Mode . . . . . . . . 11
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   7.  Work Team  . . . . . . . . . . . . . . . . . . . . . . . . . . 13
   8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 14
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 14
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 15























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1.  Overview

   One of the key aspects of the Distributed Mobility Management (DMM)
   architecture is the separation of control plane (CP) and data plane
   (DP) functions of a network element.  While data plane elements
   continue to reside on customized networking hardware, the control
   plane resides as a software element in the cloud.  This is usually
   referred to as CP-DP separation and is the basis for the IETF's DMM
   Architecture.  This approach of centralized control plane and
   distributed data plane allows elastic scaling of control plane and
   efficient use of common data plane that is agnostic to access
   architectures.

   This document identifies the functions in the DMM architecture and
   the supported deployment models.


2.  Conventions and Terminology

2.1.  Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.2.  Terminology

   All the mobility related terms are to interpreted as defined in
   [RFC6275], [RFC5213], [RFC5844], [RFC7333], [RFC7429],
   [I-D.ietf-sfc-nsh] and [I-D.ietf-dmm-fpc-cpdp].  Additionally, this
   document uses the following terms:

   Home Control-Plane Anchor (H-CPA)

      The Home-CPA function hosts the mobile node's mobility session.
      There can be more than one mobility session for a mobile node [MN]
      and those sessions may be anchored on the same or different Home-
      CPA's.  The home-CPA will interface with the home-dpa for managing
      the forwarding state.

   Home Data Plane Anchor (Home-DPA)

      The Home-DPA is the topological anchor for the mobile node's IP
      address/prefix(es).  The Home-DPA is chosen by the Home-CPA on a
      session-basis.  The Home-DPA is in the forwarding path for all the
      mobile node's IP traffic.

   Access Control Plane Node (Access-CPN)



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      The Access-CPN is responsible for interfacing with the mobile
      node's Home-CPA and with the Access-DPN.  The Access-CPN has a
      protocol interface to the Home-CPA.

   Access Data Plane Node (Access-DPN)

      The Access-DPN function is hosted on the first-hop router where
      the mobile node is attached.  This function is not hosted on a
      layer-2 bridging device such as a eNode(B) or Access Point.


3.  DMM Architectural Overview

   Following are the key goals of the Distributed Mobility Management
   architecture.

   1.  Separation of control and data Plane

   2.  Aggregation of control plane for elastic scaling

   3.  Distribution of the data plane for efficient network usage

   4.  Elimination of mobility state from the data plane

   5.  Dynamic selection of control and data plane nodes

   6.  Enabling the mobile node with network properties

   7.  Relocation of anchor functions for efficient network usage

3.1.  DMM Service Primitives

   The functions in the DMM architecture support a set of service
   primitives.  Each of these service primitives identifies a specific
   service capability with the exact service definition.  The functions
   in the DMM architecture are required to support a specific set of
   service primitives that are mandatory for that service function.  Not
   all service primitives are applicable to all DMM functions.  The
   below table identifies the service primitives that each of the DMM
   function SHOULD support.  The marking "X" indicates the service
   primitive on that row needs to be supported by the identified DMM
   function on the corresponding column; for example, the IP address
   management must be supported by Home-CPA function.








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   +=================+=======+=======+=======+=======+=======+=======+
   |  Service        | H-CPA | H-DPA | A-CPN | A-DPN |   MC  |   RC  |
   | Primitive       |       |       |       |       |       |       |
   +=================+=======+=======+=======+=======+=======+=======+
   | IP Management   |   X   |       |       |       |   X   |       |
   +-----------------+-------+-------+-------+-------+-------+-------+
   | IP Anchoring    |       |   X   |       |       |       |       |
   +-----------------+-------+-------+-------+-------+-------+-------+
   | MN Detect       |       |       |   X   |   X   |       |       |
   +-----------------+-------+-------+-------+-------+-------+-------+
   | Routing         |       |   X   |       |   X   |       |       |
   +-----------------+-------+-------+-------+-------+-------+-------+
   | Tunneling       |       |   X   |       |   X   |       |       |
   +-----------------+-------+-------+-------+-------+-------+-------+
   | QoS Enforcement |       |   X   |       |   X   |       |       |
   +-----------------+-------+-------+-------+-------+-------+-------+
   | FPC Client      |   X   |       |   X   |       |   X   |       |
   +-----------------+-------+-------+-------+-------+-------+-------+
   | FPC Agent       |       |   X   |       |   X   |       |   X   |
   +-----------------+-------+-------+-------+-------+-------+-------+
   | NSH Classifier  |       |   X   |       |   X   |       |       |
   +-----------------+-------+-------+-------+-------+-------+-------+



                    Figure 1: Mapping of DMM functions

3.2.  DMM Functions and Interfaces

3.2.1.  Home Control-Plane Anchor (H-CPA):

   The Home-CPA function hosts the mobile node's mobility session.
   There can be more than one mobility session for a mobile node and
   those sessions may be anchored on the same or different Home-CPA's.
   The home-CPA will interface with the homd-dpa for managing the
   forwarding state.

   There can be more than one Home-CPA serving the same mobile node at a
   given point of time, each hosting a different control plane session.

   The Home-CPA is responsible for life cycle management of the session,
   interfacing with the policy infrastructure, policy control and
   interfacing with the Home-DPA functions.

   The Home-CPA function typically stays on the same node.  In some
   special use-cases (Ex: Geo-Redundancy), the session may be migrated
   to a different node and with the new node assuming the Home-CPA role
   for that session.



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3.2.2.  Home Data-Plane Anchor (H-DPA):

   The Home-DPA is the topological anchor for the mobile node's IP
   address/prefix(es).  The Home-DPA is chosen by the Home-CPA/MC on a
   session-basis.  The Home-DPA is in the forwarding path for all the
   mobile node's IP traffic.

   As the mobile node roams in the mobile network, the mobile node's
   access-DPN may change, however, the Home-DPA does not change, unless
   the session is migrated to a new node.

   The Home-DPA interfaces with the Home-CPA/MC for all IP forwarding
   and QoS rules enforcement.

   The Home-DPA and the Access-DPN functions may be collocated on the
   same node.

3.2.3.  Access Control Plane Node (Access-CPN)

   The Access-CPN is responsible for interfacing with the mobile node's
   Home-CPA and with the Access-DPN.  The Access-CPN has a protocol
   interface to the Home-CPA.

   The Access-CPN is responsible for the mobile node's Home-CPA
   selection based on: Mobile Node's Attach Preferences, Access and
   Subscription Policy, Topological Proximity and Other Considerations.

   The Access-CPN function is responsible for MN's service
   authorization.  It will interface with the access network
   authorization functions.

3.2.4.  Access Data Plane Node (Access-DPN)

   The Access-DPN function is hosted on the first-hop router where the
   mobile node is attached.  This function is not hosted on a layer-2
   bridging device such as a eNode(B) or Access Point.

   The Access-DPA will have a protocol interface to the Access-CPA.

   The Access-DPN and the Home-DPA functions may be collocated on the
   same node.

3.2.5.  DMM Function Mapping to other Architectures

   Following table identifies the potential mapping of DMM functions to
   protocol functions in other system architectures.





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   +===========+==========+==========+==========+==========+==========+
   | FUNCTION  |   PMIPv6 |    MIPv6 |   IPsec  |   3GPP   | Broadband|
   +===========+==========+==========+==========+==========+==========+
   | Home-CPA  |  LMA-CPA |  HA-CPA  | IKE-CPA  | PGW-CPA  |  BNG-CPA |
   +-----------+----------+----------+----------+----------+----------+
   | Home-DPA  |  LMA-DPA |  HA-DPA  | IKE-DPA  | PGW-DPA  |  BNG-DPA |
   +-----------+----------+----------+----------+----------+----------+
   |Access-CPN |  MAG-CPN |    -     |    -     | SGW-CPN  |  RG-CPN  |
   +-----------+----------+----------+----------+----------+----------+
   |Access-DPN |  MAG-DPN |    -     |    -     | SGW-DPN  |  RG-DPN  |
   +-----------+----------+----------+----------+----------+----------+


                    Figure 2: Mapping of DMM functions


4.  Deployment Models

   This section identifies the key deployment models for the DMM
   architecture.

4.1.  Model-1: Split Home Anchor Mode

   In this model, the control and the data plane functions of the home
   anchor are separated and deployed on different nodes.  The control
   plane function of the Home anchor is handled by the Home-CPA and
   where as the data plane function is handled by the Home-DPA.  In this
   model, the access node operates in the legacy mode with the
   integrated control and user plane functions.

   The FPC interface defined in [I-D.ietf-dmm-fpc-cpdp] allows the
   control plane functions to interact with the data plane for the
   subscriber's forwarding state management.


















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                          +============+
                          |   Policy   |
             . . . . . . .|  Function  |. . . . . . .
             .            +============+            .
             .                                      .
             .                                      .
       +============+       {PMIPv6/GTP}      +============+
       |            |- - - - - - - - - - - - -|  Home-CPA  |
       |            |                         +============+
       |            |                               .
       |            |                               .  FPC
       | Access Node|                               .
       |            |                               .
       | (CPN + DPN)|                               .
       |            |                         +============+
       |   Legacy   |. . . . . . . . . . . . .|  Home-DPA  |
       +============+   UP {Tunnel/Route}     +============+
                .
                .
               [MN]


                     Figure 3: Split Home Anchor Mode

4.2.  Model-2: Seperated Control and User Plane Mode

   In this model, the control and the data plane functions on both the
   home anchor and the access node are seperated and deployed on
   different nodes.  The control plane function of the Home anchor is
   handled by the Home-CPA and where as the data plane function is
   handled by the Home-DPA.  The control plane function of the access
   node is handled by the Access-CPN and where as the data plane
   function is handled by the Access-DPN.

   The FPC interface defined in [I-D.ietf-dmm-fpc-cpdp] allows the
   control plane functions of the home and access nodes to interact with
   the respective data plane functions for the subscriber's forwarding
   state management.













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                          +============+
                          |   Policy   |
             . . . . . . .|  Function  |. . . . . . .
             .            +============+            .
             .                                      .
             .                                      .
             .                                      .
             .                                      .
       +============+    {PMIPv6/GTP}        +============+
       | Access-CPN |- - - - - - - - - - - - |  Home-CPA  |
       +============+                        +============+
             .                                      .
             .  FPC                                 .  FPC
             .                                      .
             .                                      .
             .                                      .
       +============+                        +============+
       | Access-DPN |. . . . . . . . . . .   |  Home-DPA  |
       +============+   UP {Tunnel/Route}    +============+
              .
              .
             [MN]



              Figure 4: Seperated Control and User Plane Mode

4.3.  Model-3: Centralized Control Plane Mode

   In this model, the control-plane functions of the home and the access
   nodes are collapsed.  This is a flat architecture with no signaling
   protocol between the access node and home anchors.  The interface
   between the Home-CPA and the Access-DPN is internal to the system.

   The FPC interface defined in [I-D.ietf-dmm-fpc-cpdp] allows the
   mobility controller to interact with the respective data plane
   functions for the subscriber's forwarding state management.














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                    +=======================+     +============+
                    | Home-CPA + Access-CPN |     |  Policy    |
                    |                       |-----| Function   |
                    +=======================+     +============+
                               .
                            .     .
                         .          .
                   FPC .              .  FPC
                     .                   .
                   .                       .
          +============+                    +============+
          | Access-DPN |. . . . . .  . . . .|  Home-DPA  |
          +============+ UP {Tunnel/Route}  +============+
                .
                .
               [MN]


                 Figure 5: Centralized Control Plane Mode

4.4.  Model-4: Data Plane Abstraction Mode

   In this model, the data plane network is completely abstracted from
   the control plane.  There is a new network element, Routing
   Controller which abstracts the entire data plane network and offers
   data plane services to the control plane functions.  The control
   plane functions, Home-CPA and the Access-CPN interface with the
   Routing Controller for the forwarding state management.

   The FPC interface defined in [I-D.ietf-dmm-fpc-cpdp] allows the Home-
   CPA and Access-CPN functions to interface with the Routing Controller
   for subscriber's forwarding state management.



















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                          +============+
                          |   Policy   |
             . . . . . . .|  Function  |. . . . . . .
             .            +============+            .
             .                                      .
             .                                      .
             .                                      .
       +============+    {PMIPv6/GTP}        +============+
       | Access-CPN |- - - - - - - - - - - - |  Home-CPA  |
       +============+                        +============+
             .                                      .
             .                                      .
             .                                      .
             .           +============+             .
             . . . . . . |  Routing   | . . . . . . .
                         | Controller |
                         +============+
                                .
                             .     .
                          .          .  BGP/Others
                        .              .
                      .                   .
                    .                       .
          +============+                    +============+
          | Access-DPN |. . . . . .  . . . .|  Home-DPA  |
          +============+ UP {Tunnel/Route}  +============+
                .
                .
               [MN]


                   Figure 6: Data Plane Abstraction Mode

4.5.  On-Demand Control Plane Orchestration Mode

   In this model, there is a new function Mobility Controller which
   manages the orchestration of Access-CPN and Home-CPA functions.  The
   Mobility Controller allocates the Home-CPA and Access-DPN













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   + - - - - - - - - - - - - - - - - - - - - - - - - - - -+
   |    +----------+     +----------+     +----------+    |
        |Access-CPN|     |Access-CPN|     |Access-CPN|
   |    +----------+     +----------+     +----------+    |

   |    +----------+     +----------+     +----------+    |
        | Home-CPA |     | Home-CPA |     | Home-CPA |
   |    +----------+     +----------+     +----------+    |
   + - - - - - - - - - - - - - - - - - - - - - - - - - - -+
              .                 .
              .                 .
              .                 .
              .          +============+     +============+
              .          |   Mobility |     |  Policy    |
              .          | Controller |-----| Function   |
              .          +============+     +============+
              .
              .
              .
              .          +============+
              . . . . . .|  Routing   |
                         | Controller |
                         +============+
                                .
                                .
                                .
   + - - - - - - - - - - - - - - - - - - - - - - - - - - -+
   |    +----------+     +----------+     +----------+    |
        |Access-DPN|     |Access-DPN|     |Access-DPN|
   |    +----------+     +----------+     +----------+    |

   |    +----------+     +----------+     +----------+    |
        | Home-DPA |     | Home-DPA |     | Home-DPA |
   |    +----------+     +----------+     +----------+    |
   + - - - - - - - - - - - - - - - - - - - - - - - - - - -+




                 Figure 7: On-Demand CP Orchestration Mode


5.  IANA Considerations

   This document does not require any IANA actions.






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6.  Security Considerations

   The control-plane messages exchanged between a Home-CPA and the Home-
   DPA must be protected using end-to-end security associations with
   data-integrity and data-origination capabilities.

   IPsec ESP in transport mode with mandatory integrity protection
   should be used for protecting the signaling messages.  IKEv2 should
   be used to set up security associations between the Home-CPA and
   Home-DPA.

   There are no additional security considerations other than what is
   presented in the document.


7.  Work Team

   This document reflects contributions from the following work team
   members:

   Seil Jeon

      seiljeon@av.it.pt

   Younghan Kim

      younghak@ssu.ac.kr

   Vic Liu

      liuzhiheng@chinamobile.com

   Danny S Moses

      danny.moses@intel.com

   Marco Liebsch

      liebsch@neclab.eu

   Carlos Jesus Bernardos Cano

      cjbc@it.uc3m.es








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8.  Acknowledgements

   This document is a result of DMM WT#4 team discussions and ideas
   taken from several DMM WG presentations and documents including,
   draft-sijeon-dmm-deployment-models, draft-liu-dmm-deployment-scenario
   and others.  The work teams would like to thank the authors of these
   documents and additionally the discussions in DMM Working group that
   helped shape this document.


9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
              RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

9.2.  Informative References

   [I-D.ietf-dmm-fpc-cpdp]
              Liebsch, M., Matsushima, S., Gundavelli, S., Moses, D.,
              and L. Bertz, "Protocol for Forwarding Policy
              Configuration (FPC) in DMM", draft-ietf-dmm-fpc-cpdp-03
              (work in progress), March 2016.

   [I-D.ietf-sfc-nsh]
              Quinn, P. and U. Elzur, "Network Service Header",
              draft-ietf-sfc-nsh-04 (work in progress), March 2016.

   [RFC5213]  Gundavelli, S., Ed., Leung, K., Devarapalli, V.,
              Chowdhury, K., and B. Patil, "Proxy Mobile IPv6",
              RFC 5213, DOI 10.17487/RFC5213, August 2008,
              <http://www.rfc-editor.org/info/rfc5213>.

   [RFC5844]  Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
              Mobile IPv6", RFC 5844, DOI 10.17487/RFC5844, May 2010,
              <http://www.rfc-editor.org/info/rfc5844>.

   [RFC6275]  Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
              Support in IPv6", RFC 6275, DOI 10.17487/RFC6275,
              July 2011, <http://www.rfc-editor.org/info/rfc6275>.

   [RFC7333]  Chan, H., Ed., Liu, D., Seite, P., Yokota, H., and J.
              Korhonen, "Requirements for Distributed Mobility
              Management", RFC 7333, DOI 10.17487/RFC7333, August 2014,
              <http://www.rfc-editor.org/info/rfc7333>.



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   [RFC7429]  Liu, D., Ed., Zuniga, JC., Ed., Seite, P., Chan, H., and
              CJ. Bernardos, "Distributed Mobility Management: Current
              Practices and Gap Analysis", RFC 7429, DOI 10.17487/
              RFC7429, January 2015,
              <http://www.rfc-editor.org/info/rfc7429>.


Author's Address

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

   Email: sgundave@cisco.com



































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