Network Working Group                                           V.Liu
Internet Draft                                            ChinaMobile
Intended status: Standards Track                                D.Liu
Expires: Mar 18, 2016                                         Alibaba
                                                              H. Chan
                                                   Huawei Technologies
                                                               H. Deng
                                                          China Mobile
                                                                X.Wei
                                                   Huawei Technologies
                                                      October 19, 2015



    Distributed mobility management deployment scenario and architecture
                   draft-liu-dmm-deployment-scenario-05


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   This Internet-Draft will expire on March 19,2016.

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   This document is subject to BCP 78 and the IETF Trust's Legal
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   Section 4.e of the Trust Legal Provisions and are provided without
   warranty as described in the Simplified BSD License.

   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.

Abstract

   This document discusses the deployment scenario of distributed
   mobility management. The purpose of this document is to trigger the
   discussion in the group to understnad the DMM deployment scenario
   and consideration from the operator's perspective.

Table of Contents



   Table of Contents ................................................ 2
   1. Introduction .................................................. 2
   2. Conventions used in this document.............................. 3
      2.1. Terminology .............................................. 3
   3. Deployment Scenario and Model of DMM........................... 3
   4. Network Function Virtualization Scenario....................... 4
      4.1. Network function virtualization deployment architecture... 4
      4.2. Control and data plane separation......................... 6
      4.3. Mobility management architecture.......................... 6
      4.4  NFV based deployment architecture......................... 7
   5. SIPTO deployment scenario...................................... 8
   6. WLAN deployment scenario....................................... 9
   7. Conclusion ................................................... 10
   8. Security Considerations....................................... 10
   9. IANA Considerations .......................................... 10
   10. Normative References......................................... 11
   11. Informative References....................................... 11
   12. Acknowledgments ............................................. 11
   Authors' Addresses .............................................. 12
1. Introduction

   Distributed mobility management aims at solving the centralized
   mobility anchor problems of the traditional mobility management
   protocol.  The benefit of DMM solution is that the data plane traffic
   does not need to traverse the centralized anchoring point.  This
   document discusses the potential deployment scenario of DMM.  The
   purpose of this document is to help the group to reach consensus


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   regarding the deployment model of DMM and then develop the DMM
   solution based on the deployment model.

2. Conventions used in this document

   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].

2.1. Terminology

   All the general mobility-related terms and their acronyms used in
   this document are to be interpreted as defined in the Mobile IPv6
   base specification [RFC6275], in the Proxy mobile IPv6 specification
   [RFC5213], and in Mobility Related Terminology [RFC3753].  These
   terms include the following: mobile node (MN), correspondent node
   (CN), and home agent (HA) as per [RFC6275]; local mobility anchor
   (LMA) and mobile access gateway (MAG) as per [RFC5213], and context
   as per [RFC3753].

   In addition, this draft introduces the following terms.

   Location information (LI) function

   is the logical function that manages and keeps track of the internet
   work location information of a mobile node which may change its IP
   address as it moves.  The information may associate with each session
   identifier, the IP routing address of the MN, or of a node that can
   forward packets destined to the MN.

   Forwarding management (FM)

   is the logical function that intercepts packets to/from the IP
   address/prefix delegated to a mobile node and forwards them, based
   on internetwork location information, either directly towards their
   destination or to some other network element that knows how to
   forward the packets to their ultimate destination.  With data plane
   and control plane separation, the forwarding management may be
   separated into a data-plane forwarding management (FM-DP) function
   and a control-plane forwarding management (FM-CP) function.

3. Deployment Scenario and Model of DMM

   As discussed in the DMM requirement document, the centralized
   mobility management has several drawbacks.  The main problem of the
   centralized mobility management protocols is that all the traffic
   need to anchor to a centralized anchor point.  This approach does not


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   cause any problem in current mobile network deployment but in the
   scenario that will be discussed later in this document, centralized
   mobility management protocols will have many drawbacks and it is
   believed that DMM is more suitable in that scenario.

   The main deployment scenario discussed in this document is divided
   into three scenarios.  The first one is the network function
   virtualization scenario. In this scenario, the mobile core network's
   control plane function is centralized in the mobile cloud.
   Apparently, deploying the data plane function also in the same
   centralized mobile cloud is not optimized from the traffic
   forwarding's perspective. For the control plane The MME and PGW-F
   are implemented by NFV. For the dataplane the PGW-F/SGW-F can
   weither be implemented by NFV or lagacy devices.  The second
   deployment scenario is the SIPTO/LIPA scenario which is discussed in
   3GPP. In this scenario, DMM can provide optimized traffic offloading
   solution. The Third deploy scenario is the WLAN scenario. In this
   scenario, the AC is implemented in the cloud and the authentication
   status can maintained as the terminal move from one AP to another.

4. Network Function Virtualization Scenario

   This section discusses network function virtualization scenario, the
   associated control - data plane separation and the possible mobility
   management functions to support this scenario.

4.1. Network function virtualization deployment architecture

   The network function virtualization scenario is shown in Figure 1.



















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                    Mobile Cloud
             ...........
                  ('             ')
                (                )))
               (((  +-----------+ )))
              ((    |Mobile Core|    )))
              ((    |MME+P/SGW-C|    )))
              (((   +-----------+   )))
                 ('..............')
                                  |
                          | IP Transit Network
                      (.........)
                    (           )) MN-Internet communication
                   (           ^ ))
            ^ > > >(           ^  ))> > > > > > > > >
            ^       ((         ^  )                  v
            ^        (.........^.)                   v
            ^ +-------|     |  ^|                    v
            ^ |             |  ^+--------------+     v
            ^ |             |  < <             |     v  MN-MN communication
            ^ |             |    ^             |     v
      +--------------+    +--------------+    +--------------+
      |Access Network|    |Access Network|    |Access Network|
      |  PGW-F/SGW-F  |   |  PGW-F/SGW-F  |   |  PGW-F/SGW-F  |
      +--------------+    +--------------+    +--------------+
            ^                    ^                   v
            ^                    ^                   v
        +---------+         +---------+         +---------+
        |   MN     |        |    MN   |          |   MN     |
        +---------+         +---------+         +---------+

   Figure 1: Network function virtualization deployment architecture

   In this architecture, the mobile core include MME and PGW-F is
   located in the cloud data center, which can be the operator's
   private cloud using NFV. The access network cantains PGW-F/SGW-F is
   connected through an IP transit network. The PGW-F/SGW-F may also
   implement by NFV of small data center in convergence layer. The
   architecture of NFV based Mobile Core is shown in Figure 2.








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   ---------------------------------     -------------------
   | ----------------------------- |     |   MANO LAYER     |
   | |        OSS/BSS LAYER      | |     |                  |
   | ----------------------------- |     |   -------------  |
   |               |               |     |   |Orchestrator| |
   | ----------------------------- |     |   -------------  |
   | |      VNF LAYER            | |     |         |        |
   | | ---------       ------    | |     |   -------------  |
   | | |P/SGW-C|      |  MME |   | |-----|  |    VNFM    |  |
   | | ---------         ------    |     |   -------------  |
   | ----------------------------- |     |        |         |
   |               |               |     |        |         |
   | ----------------------------- |     |   -------------  |
   | |      NFVI LAYER           | |-----|  |     VIM     | |
   | ----------------------------- |     |   -------------  |
   ---------------------------------     -------------------
       Figure 2: NFV based Mobile Core Architecture

In Figure 2, the MANO layer contains Orchestrator, VNFM and VIM. The
Orchestrator is in charge of top-down service and source monitor and
fulfillment. VNFM is incharge of manage the VNFs. And VIM normally is
the Openstack which provide management of the whole virtualization
layer.

4.2. Control and data plane separation

   The cloud based mobile core network architecture implies separation
   of the control and data planes.  The control plane is located in the
   cloud and the data plane should be distributed. Otherwise, all the
   data traffic will go through the cloud which is obviously not
   optimized for the mobile node to mobile node communication. For the
   mobile node to Internet communication, the Internet access point is
   normally located in the metro IP transit network. In this case, the
   mobile node to Internet traffic should also go through the Internet
   access point instead of the mobile core in the cloud.

   However, in some deployment scenario, the operator may choose to put
   the mobile core cloud in the convergence layer of IP metro network.
   In this case, the Internet access point may co-located with the
   mobile core cloud. In this case, the mobile node to Internet traffic
   may go through the mobile core cloud.

4.3. Mobility management architecture

   Since the control plane and data plane are separated and the data
   plane is distributed, traditional mobility management cannot meet


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   this requirement. Distributed mobility management or SDN based
   mobility management may be used in this architecture to meet the
   traffic forwarding requirement (e.g.  MN to MN and MN to Internet
   traffic should not go through from the mobile core cloud.). The
   traditional mobility management functions is not separating the data
   plane from the control plane.  Basic mobility management functions
   include location information (LI) function and Forwarding management
   (FM). The former is a control plane function. The latter can be
   separated into data plane forwarding management (FM-DP) and control
   plane forwarding management (FM-CP).



   The data plane function is FM-DP, while the control plane functions
   include FM-CP and LI.  Then the control plane functions in the cloud-
   based mobile core includes LI and FM-CP.  They are of cause other
   functions in the control plane such as policy function. The

   distributed data plane may have multiple instances of FM-DP in the
   network.

                   core network controller

                        +---------+
                        |LI, FM-CP|
                        +---------+

        +-------+        +-------+        +-------+
        | FM-DP |        | FM-DP |        | FM-DP |
        +-------+        +-------+        +-------+



   Figure 2: Mobility management functions with data plane - control
   plane separation under one controller When the control of the access
   network is separate from that of the core, there will be separate
   controllers as shown in Figure 3.

    Access network controller               Core network controller

             +---------+                            +---------+
             |LI, FM-CP|                            |LI, FM-CP|
             +---------+                            +---------+

      +-------+       +-------+              +-------+       +-------+
      | FM-DP |       | FM-DP |              | FM-DP |       | FM-DP |
      +-------+       +-------+              +-------+       +-------+


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   Figure 2: Mobility management functions with data plane - control
   plane separation with separate control in core and in access
   networks.











































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4.4. NFV based deployment architecture

Here is the deployment architecture in NFV.

             -------------             ------------
            | Yang Model  |           | Tosca Model|
             -------------             ------------
-------------------------------------------------------------------------
| [VNFO]              -------------------------------------------------- |
|  ------------    |  --------------------   ------------------------ ||
| |    NBI     |   | |  ----- ----- ----- | | ---------------------- |||
|  ------------    | |  |NSD| |FGD| |VLD| | ||VNFD(LI,FM-CP)(FD-DP) ||||
|                  | |  ----- ----- ----- | | ---------------------- |||
|  ------------    |  --------------------   ------------------------ ||
| | API Router|    |                  DataBase                        ||
|  ------------     ---------------------------------------------------|
|                                                                      |
|  ------------                                                        |
| |Core Engine|                                                        |
|  ------------                                                        |
-------------------------------------------------------------------------
      ------------     ------------    ------------
     |VNFM Driver|     |VIM Driver|     |PNF Driver|
      ------------     ------------    ------------
 ----------------------------------------------     -----------------
|   [VNFM]                                    |    |[PNF]           |
|   VNF Life cycle management;                |    |   ------------ |
|   VNF configuration;                        |    |   |   OVS    | |
|   VNF update;                               |    |   ------------ |
|   VNF status monitor;                       |     -----------------
|   VNF Auto healing/Scale in/Scale out       |
 ----------------------------------------------
-----------------------------------------------------------------
|                           Vim                                  |
-----------------------------------------------------------------
   --------------------------------------------------
   |[VNF]  LI Slicing ; FM-CP Slicing; FD-DP Slicing |
   --------------------------------------------------
                                Figure 3 Deployment architecture



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5. SIPTO deployment scenario

   The Second deployment scenario is the SIPTO scenario which is
   discussed in 3GPP. DMM is believed to be able to provide dynamic
   anchoring. It allows the mobile node to have several anchoring
   points and to change the anchoring point according to the
   application requirement. In SIPTO scenario, the gateway function is
   located very near to the access network and to the user.  If using
   current centralized mobility management, the traffic will need to
   tunnel back to the previous anchor point even when the mobile node
   has changed the point of attachment to a new one. Figure 3 shows the
   architecture of SIPTO.




































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                         +---------+
                         |   GGSN  |
                         +---------+
                             |
                             |
           ------------------------------------------
           |                 |             |         |
       +---------+    +---------+    +---------+   +---------+
       |   MSC   |    |   SGSN  |    |   MSC   |   |   SGSN   |
       +---------+    +---------+    +---------+   +---------+
           |             |    |         |    |          |
             ------------      ----------      ---------
                  |            |                  |
         <<<<<<<<<|     <<<<<<<|                  |>>>>>>>>
                +---------+    +---------+     +---------+
                |   GGSN  |    |   GGSN   |   |   GGSN   |
                |    RNC  |    |    RNC   |   |    RNC   |
                +---------+    +---------+     +---------+
                   ^|                 |^            ^|
                   ^|                 |^            ^|
             ---------------          |^            ^|
            ^|             |^         |^            ^|
       +---------+     +---------+    +---------+   +---------+
       |  NodeB  |     |  NodeB  |    |  NodeB  |   |  NodeB  |
       +---------+     +---------+    +---------+   +---------+
           ^|             ^|                            ^|
       +---------+        +---------+              +---------+
       | Terminal|   ->   | Terminal|    -> ->     | Terminal|
       +---------+        +---------+              +---------+                                                                          Figure 4 SIPTO Scenario

6. WLAN deployment scenario

   The Third deployment scenario is the WLAN scenario. DMM can enable
   the AC in the cloud. The cloud AC and maintain the authentication
   and connection status. As the terminal move from one AP to another,
   it still can have the connection.

                    ...........
                  ('             ')
               (((  +-----------+ )))
              ((    |  Mobile AC |   )))
              (((   +-----------+   )))
                 ('..............')
                          |


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                          | IP Transit Network
                      (.........)
                    (           ))
                   (            ))
                   (             ))
                   ((           )
                    (..........)
            +-----------------------------------+
            |                |                      |
            |                |                      |
            |                |                      |
      +----------+        +-----------+        +----------+
      |     AP     |        |     AP     |        |     AP     |
      +----------+        +-----------+        +----------+
         |                             |             |
      +---------+        +---------+            +---------+
      | Terminal|   ->   | Terminal|    ->     | Terminal|
      +---------+         +---------+           +---------+
                Figure 5 WLAN deployment scenario







7. Conclusion

   This document discusses the deployment scenario of DMM.  Three types
   of deployment scenario is discussed in this document.  Further types
   of deployment scenario can be added to this document according to
   the progress of the group's discussion.



8. Security Considerations

   N/A

9. IANA Considerations

   N/A






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10. Normative References

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

   [2]  Crocker, D. and Overell, P.(Editors), "Augmented BNF for
         Syntax Specifications: ABNF", RFC 2234, Internet Mail
         Consortium and Demon Internet Ltd., November 1997.

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

   [RFC2234] Crocker, D. and Overell, P.(Editors), "Augmented BNF for
             Syntax Specifications: ABNF", RFC 2234, Internet Mail
             Consortium and Demon Internet Ltd., November 1997.

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

   [RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology",
             RFC 3753, June 2004.

   [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
             and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.

   [RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
             in IPv6", RFC 6275, July 2011.



11. Informative References

   [3]  Faber, T., Touch, J. and W. Yue, "The TIME-WAIT state in TCP
         and Its Effect on Busy Servers", Proc. Infocom 1999 pp. 1573-
         1583.

   [Fab1999] Faber, T., Touch, J. and W. Yue, "The TIME-WAIT state in
             TCP and Its Effect on Busy Servers", Proc. Infocom 1999 pp.
             1573-1583.

12. Acknowledgments

   This document was prepared using 2-Word-v2.0.template.dot.






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Authors' Addresses

   Vic Liu
   China Mobile
   32 Xuanwumen West AVE, Xicheng, Beijing
   Email: liuzhiheng@chinamobile.com

   Dapeng Liu
   Alibaba

   Email: max@dotalks.com


   H Anthony Chan
   Huawei Technologies
   5340 Legacy Dr. Building 3
   Plano, TX 75024
   USA
   Email: h.a.chan@ieee.org


   Hui Deng
   China Mobile
   32 Xuanwumen West AVE, Xicheng, Beijing
   Email: denglingli@chinamobile.com


   Xinpeng Wei
   Huawei Technologies

   Email: Xinpengwei@huawei.com

















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