Internet Engineering Task Force                                  J. Yang
Internet Draft                                                    Huawei
Intended status: Informational                                    T. Sun
Expires: September 2009                                     China Mobile
                                                                  S. Fan
                                                         March 4, 2009

     Multi-interface Connection Manager Implementation and Requirements
             draft-yang-mif-connection-manager-impl-req-00.txt


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Abstract





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    This document presents the current implementation and problems
encountered in practice of the "Connection Manager."  The problems to be
addressed exist within an operating system (OS) and platforms above OS.
This document focuses on levels above OS and presents the solutions,
especially for terminals with multiple interfaces. The scenarios of
interface selections are described.
Table of Contents


   1. Introduction................................................2
   2. Scenarios of multiple interfaces.............................2
   3. Implementation of Connection Manager.........................3
      3.1. Connection Handle.......................................3
      3.2. Interface based connection handle.......................3
      3.3. Interface and Access Node based connection handle........4
   4. Problems Encountered In Practice.............................4
      4.1. Pre-configuration of connection handle in UE............4
      4.2. Automatic selections based on OS........................5
      4.3. Automatic selections based on  applications.............5
   5. Conclusions.................................................5
   6. Informative References.......................................5
   Author's Addresses.............................................6

1. Introduction

   Along with the development of variant access technologies, terminals
   are capable of being connected with different networks through
   multiple interfaces. These interfaces may belong to one or multiple
   network domains.

   Applications on terminals need to connect with appropriate network
   domains through interfaces for the requirement of services, or on
   behalf of users' preference.

   This document describes an implementation of interface selection by
   terminal applications, especially for accessing different network
   domains. A connection management approach is presented. In addition,
   the document also identifies the problems caused by different
   implementations among variant vendors.  This will lead to
   difficulties on customization and development of terminal software.

2. Scenarios of multiple interfaces

   A terminal may have multiple interfaces for network connection, e.g.
   interfaces for connection with GRPS, WiFi, and BlueTooth. An


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   application sets up a network connection through one of these
   interfaces. In fact, different network connections may correspond to
   different network domains, in which different services are provided.
   Therefore, an application needs to select the right interface for
   network access.

3. Implementation of Connection Manager

3.1. Connection Handle

   In terminal, applications use "connection handle" to dial-up or setup
   connections. This connection handle can be defined in two ways:

   o Interface based connection handle.

   o Interface and access node based connection handle.

   Application may select the appropriate connection handle to setup
   connections according to configured policy.

3.2. Interface based connection handle

   As illustrated in Figure 1, a UE have three types of interfaces, i.e.,
   GRPS, WiFi and Bluetooth. Each interface has one corresponding
   connection handle as Connect 1, Connect 2 and Connect 3. When an
   application on the terminal starts to connect with the networks, the
   system selects the connection handle and configures parameters (e.g.,
   SSID, default Proxy, APN parameter) based on the specific requirement
   of the application.

   +----+            +------------------------------+
   |    |   GPRS     |Connect1->GPRS internet GPRS  |
   | UE |------------|                              |
   |    |            +------------------------------+
   |    |
   |    |            +------------------------------+
   |    |   WiFi     |Connect2->WLAN internet WLAN  |
   |    |------------|                              |
   |    |            +------------------------------+
   |    |
   |    |            +------------------------------+
   |    | BlueTooth  |Connect3->Bluetooth_internet  |
   |    |------------|                              |
   |    |            +------------------------------+
   +----+

                Figure 1 Interface based connection handle.


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3.3. Interface and Access Node based connection handle

   As illustrated in Figure 2, a UE have three network interfaces, i.e.,
   GRPS, WiFi and Bluetooth for network access. As for these interface,
   each has more than one connection handles. Therefore, a connection
   handle is determined by the network interface type and access
   parameters. When an application starts to connect with the network,
   it may implement based on local policy to select the appropriate
   connection handle for this specific application.

   +----+         Connect1->APN= CMWAP:GRPS
   |    | GPRS   /
   |    |--------| Connect2->APN=CMNET:GPRS
   |    |        \
   |    |         Connect1->APN= CMWAP:GRPS
   |    |
   |    |         Connect4->SSID=AP1:WLAN
   | UE |   WiFi /
   |    |--------| Connect5->SSID=AP2:WLAN
   |    |        \
   |    |         Connect6->SSID=AP3:WLAN
   |    |
   |    |           Connect7->deviceID = B1:BlueTooth
   |    |BlueTooth /
   |    |---------|
   |    |          \Connect8->deviceID = B2:BlueTooth
   +----+
            Figure 2 Interface and Node based connection handle.

4. Problems Encountered In Practice

   As described in 3.2 and 3.3, a terminal may have multiple interfaces
   and each interface may have multiple connection handles for different
   access nodes. This section presents three implementation approaches
   and the corresponding problems encountered.

4.1. Pre-configuration of connection handle in UE

   Currently, connection handle of the applications have been pre-
   configured on the OS. When UE connects to a network, it uses the pre-
   configured parameters automatically.

   The problem is that the pre-configured parameters are different among
   different vendors. Therefore, the applications should be designed
   into different versions for the variant parameter settings. Moreover,
   when an application is downloaded or updated, UE should check whether



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   the application is applicable. These increase the complexities and
   restricts the development of UE applicaitons.

4.2. Automatic selections based on OS

   An application may rely on OS for the selection of a connection
   handle which is one of the default connection handles maintained by
   the OS.

   The problem is that an OS may define one or several default
   connection handles while, they may not suitable for all applications.

4.3. Automatic selections based on  applications

   All connection handles may be tried one by one by an application
   until a connection is established.

   The problem is this will cause a long time waiting and bad user
   experience. Usually, successful connection may be identified in two
   steps, i.e., network access success and service startup success.
   Generally, one attempts to connect to a network may take about 3
   second before time out. If every connect handle try 3 times, then it
   may take about 9 second in all for network connection. After the link
   is established, the application tries services according to
   application layer protocol, such as registration etc. This may take
   about 4-12 seconds before time out. Therefore, it takes about 7-21
   second for an application getting connected with network. This will
   not be a good experience for a user.

5. Conclusions

   The suggestions for standardization are summarized as follows.

   o Manager for multiple interfaces to achieve better user experiences.

   o The connection manager is implemented through both network side
      and terminal side.

   o Reduces the complexity of new application installation for diverse
      terminals.

6. 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.


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

Author's Addresses

   Jian Yang
   Huawei Technology
   Mobile department, Huawei Building
   Haidian District,
   Beijing 100086
   China
   Email: jian.yang@huawei.com

   Tao Sun
   China Moible
   53A,Xibianmennei Ave.,
   Xuanwu District,
   Beijing 100053
   China
   Email: suntao@chinamobile.com

   Shunan Fan
   Huawei Technology
   Mobile department, Huawei Building
   Haidian District,
   Beijing 100086
   China
   Email: fanshunan@huawei.com



















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