Internet Engineering Task Force                               Y. Zhang
Internet Draft                                            Leadcoretech
Intended status: Informational                                    T. Sun
Expires: August 2009                                        China Mobile
                                                                 H. Chen
                                                      February 27, 2009

        Multi-interface Network Connection Manager in Arena Platform

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Internet-Draft  Connection Manager in Arena Platform     February 2009

    This document presents a "Connection Manager" model implemented in
the platform Arena, a mobile OS based on Linux. The introduction of
Connection Manager brings two major benefits in Arena. First, it
logically decouples the underlining connection approach with the
connection management. Second, it plays a central role which executes
the policy of OS, especially for multiple interfaces.
Table of Contents

   1. Introduction................................................2
   2. Scenario....................................................2
   3. Solution....................................................5
      3.1. Work Flow..............................................5
      3.2. Interface Reuse.........................................6
      3.3. Link route consideration................................6
   4. Conclusions.................................................7
   5. References..................................................7

1. Introduction

    In current practices, most of applications maintain network by
themselves. They directly connect to the network with given parameters
leading to the coupling of operation and network management in logic
level. Moreover, such type of mechanism does not meet variant
requirements in multiple interfaces situations.

    This document presents a Network Connect Manager solution which
abstracts the network connect function to a class which can be used by
the functions to get connection management services. The access
approaches, parameter settings, management policies and connection
management solicitation processes are handled based on OS predefined or
application customized interface settings and are separate with the
Network Connect Manager. In this way, the connection link related
operations are separated with network management logically. This also
makes it possible to address multiple interface cases.

    This document will illustrate the scenarios where connection manger
applies, the link management model and the procedure to use connection
2. Scenario

    There are three modes of interface selection as depicted in Figure 1.

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These modes are summarized as follows.

UE                                                +-------------------------+
 |                +-----------------------+       | Default Wifi Internet   |
 |                |Default Wifi Internet  |       |Connect Process          |
 | User Select    |SSID:****              |======>|Disconnect Process       |
 |--------------->|Password:****          |       |Link Status Query Process|
 |                |......                 |       |Parameter Setting Process|
 |                +-----------------------+       |Parameter Query Process  |
 |                                                |......                   |
 |                                                +-------------------------+
 |                 +-----------------------+      +-------------------------+
 |                 |Default GPRS Internet  |      | Default GPRS Internet   |
 |System automatic |Access Point Name:**** |      |Connect Process          |
 |---------------->|User Name:****         |      |Disconnect Process       |
 |   select        |Password:****          |=====>|Link Status Query Process|
 |                 |Quality Of Service:****|      |Parameter Setting Process|
 |                 |......                 |      |Parameter Query Process  |
 |                 +-----------------------+      |......                   |
 |                            :                   +-------------------------+
 |                            :
 |                +------------------------+      +-------------------------+
 |                |Customize GPRS WAP      |      |    Customize GPRS WAP   |
 |                |Default GPRS Internet   |      |Connect Process          |
 |User Customize  |User Name:****          |      |Disconnect Process       |
 |--------------->|Password:****           |=====>|Link Status Query Process|
 |                |Uplink Rate:****        |      |Parameter Setting Process|
 |                |Downlink Rate:****      |      |Parameter Query Process  |
 |                |......                  |      |......                   |
 |                +------------------------+      +-------------------------+
                Figure 1 There modes of interface selection

      Interface Selection by an Application. If an application selects a
      system default interface, it calls those default link management
      service interfaces offered by the Network Connection Manager.

      System Automatic Selection. If an application attempts to get
      connected without specific requirements, the system will evaluate
      various factors such as bandwidth, cost, stability, then select an
      interface automatically for the application.

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      Creating New Interface based on Requirements. When all default
      interfaces can't meet the requirement of an application, the
      application can customize a new connect interface and configure
      the connection parameters, define the detailed processes such as
      connect, disconnect, status query, parameter settings and query.
      Then the interface is registered to the Connection Manager. In
      this way, a new interface is created and can be used as other
      interfaces in Connection Manager.

Figure 2 illustrates the mechanism of Connection Manager model. All the
interfaces must register with the Connection Manager and link manage
operations carry out via the multiple network connect interfaces.

                    +--------+          +-------+            ||
    +-----+ Select  |Default | Register |       |            ||
    |App 1|-------->|GPRS    |--------->|       |--Connect-->||
    +-----+         |MMS     |          |       | Disconnect ||G
                    +--------+          |Network|            ||P
    +-----+ Selec   +--------+          |       |            ||R
    |App 2|-------->|Default | Register |       |            ||S
    +-----+         |GPRS    |--------->|       |--Connect-->||
                    |Internet|          |       | Disconnect ||
                    +--------+          |       |            ||
        :             :                 |Connect|            ||
        :             :                 |       |            ||
                    +---------+         |       |            ||
    +-------+Select |Customize| Register|       |            ||
    |App n-1|------>|GPRS     |-------->|       |--Connect-->||C
    +-------+       |Internet |         |Manager| Disconnect ||S
                    +---------+         |       |            ||D
                                        |       |            ||
                                        |       |            ||
                    +---------+         |       |            ||W
    +-----+ Select  |Customize| Register|       |            ||i
    |App n|-------->|Wifi     |-------->|       |--Connect-->||f
    +-----+         |Internet |         |       | Disconnect ||i
                    +---------+         +-------+            ||:

                 Figure 2 Network Connection Manager Model

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3. Connection Manager

        3.1. Work Flow

      Figure 3 demonstrates the working flow of the Network Connection
   Manager. In the figure an application select a default interface
   named "Default GPRS Internet" to connect with the network.

       Application         Socket     Interface   Connection Manager
        |                         |            |                          |
        |        Select Default   |            |                          |
    (1) |------GPRS Interface-----|----------->|                          |
        |                         |            |                          |
    (2) |                         |            |----Interface Register--->|
        |                         |            |                          |
    (3) |-------------- Connect Request(Default GPRS Internet)----------->|
        |                         |            |                          |
    (4) |                         |            |<---Call Connect Process--|
        |                         |            |                          |
    (5) |<------------------------|------------|------Connect Response----|
        |                         |            |                          |
    (6) |-------Create Socket---->|            |                          |
        |                         |            |                          |
    (7) |-------Bind Socket------>|            |                          |
        |                         |            |                          |
        |      Normal Socket      |            |                          |
    (8) |<-----Communication----->|            |                          |
        |                         |            |                          |
    (9) |-----Close Socket------->|            |                          |
        |                         |            |                          |
        |                         |            |                          |
    (10)|------------ Disconnect|Request(Default GPRS Internet)---------->|
        |                         |            |                          |
    (11)|                         |            |<-Call Disconnect Process-|
        |                         |            |                          |
    (12)|<------------------------|------------|--Disconnect Response-----|
        |                         |            |                          |
        |                         |            |                          |

                Figure 3 Network Connection Manager Work Flow

      The steps are listed as below:

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      1) An application selects a default interface named "Default GPRS
         Internet" to connect with network;

      2) The Default GPRS Internet interface registers with the
         Connection Manager;

      3) An application requests the Connection Manager to connect with
         network via Default Network Interface connect interface;

      4) When the Connection Manager receives the request of connection,
         the Connection Manager will select one interface according to
         the parameter required. The implementation of the interface on
         connection is called to establish link for network access.

      5) The Connection Manager informs the success of connection to the
         application and saves the information about this link such as
         PDP context, IP address, DNS etc.;

      6) From step (6) to step (9), the application creates a socket and
         binds it with the IP address of the active link. The
         communication is established via the socket. The socket will be
         closed at the end of the communication.

      7) The disconnect procedures from step(10) to (12) are similar as,
         previous procedures for connection establishment.

      Note: In the case of interface customization, a new interface
   should be created through configuring parameters and implement
   network management at step (1).

        3.2. Interface Reuse

      The Connection Manager has the ability to make connections work
   simultaneously. Multiple applications can share a connect interface
   at the same time. In such situations, operations such as link
   establish and disconnect will be shared.

        3.3. Link route consideration

   Under the circumstance that multiple interfaces are connected
   simultaneously, applications should bind socket with IP address of
   the corresponding interface to make sure that each socket created by
   every application exactly communicate via its respective link and

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4. Conclusions

   The Connection Manager model in Arena platform improves the
   efficiency for application developers and makes it convenient to
   manage connections over variant network resources. Further work will
   be conducted on link resource management, task scheduling and policy

5. Informative References

   [I-D.hui-ip-multiple-connections-ps] Hui, M. and H. Deng, "Problem
         Statement and Requirement of Simple IP Multi-homing of the
         Host", draft-hui-ip-multiple-connections-ps-01 (work in
         progress), November 2008.

   [I-D.blanchet-mif-problem-statement] Blanchet, M., "Multiple
         Interfaces Problem Statement", draft-blanchet-mif-problem-
         statement-00 (work in progress), December 2008.

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         Authors' Addresses

   Yan Zhang
   Leadcoretech Ltd.
   333,qinjiang Ave.,
   Xuhui District,
   Shanghai 200233

   Tao Sun
   China Moible
   53A,Xibianmennei Ave.,
   Xuanwu District,
   Beijing 100053

   Hua Chen
   Leadcoretech Ltd.
   333,qinjiang Ave.,
   Xuhui District,
   Shanghai 200233

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