JP2007249764A - Automatic handover system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To individually and dynamically change networks used by services such as an IP telephone, a browser and mail without significantly damaging the development efficiency and portability of an application and the convenience of a user in portable terminal equipment capable of utilizing the plurality of networks. <P>SOLUTION: A transport layer API hook module hooks the API of a transport layer such as socket API called from the application 1, respective protocol processing parts (such as an SIP processing part 41 and an HTTP processing part 42) analyze the information of the API through a handover manager 3, and information required for handover is stored in storage parts (such as an SIP storage part 411 and an HTTP storage part 421). When the handover is requested from the application 1 or a communication module 5, the handover manager 3 executes handover processing using the information required for the handover, which is stored beforehand. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an automatic handover system and method for realizing a handover of a mobile terminal device which is a mobile device for mobile communication.

  Conventionally, when the network availability changes, for example, an application that operates on a mobile terminal device in a situation where the mobile terminal device can use a wireless LAN from a state where only the mobile phone network can be used To change the network that is currently in use, the application itself changes the network, or common middleware for each protocol (SIP, HTTP, etc.) that the application uses to provide the service changes the network. Processing had to be done.

  In the former method, all applications that use the network must implement complicated and routine processing (specified by each protocol) for handover that changes the network inside each application, The development man-hours for each application increase, resulting in high costs and waste.

  In the latter method, since it is a condition that each application uses common middleware, there is a problem that the application has poor versatility and lacks portability.

  Note that Patent Document 1, which is a related art in the related field, describes a communication terminal device that discloses performing a transport layer process conventionally known in a transport layer.

JP 2004-266330 A

  The above prior art has the following problems.

  That is, the first problem of the prior art is that it is wasteful to implement a handover process inside an application from the viewpoint of application development. The reason is that there are many processes defined by the protocol to be used for realizing the handover, and each application implements such routine processes.

  The second problem of the prior art is that when the handover process is implemented with common middleware for each protocol, the portability of the application is deteriorated. The reason is that the application must use common middleware for each protocol, and in the case of transplanting an application in which protocol processing has been mounted in advance, drastic modification is required.

  Moreover, in the prior art described in Patent Document 1, there is no description about the relationship between the network change process and the process in the transport layer.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a method for realizing handover in a portable terminal device that can use a plurality of networks without sacrificing application development efficiency and portability. It is to provide.

  Referring to FIG. 1, the automatic handover method of the present invention refers to a transport layer API hook that hooks a transport layer API (socket API, etc.) (in the OSI 7 layer model) that is executed when an application program uses a network. It is characterized by having a module, a handover manager that is called from the transport API hook module and manages handover processing, and a protocol processing unit that executes processing for each protocol used by an application to provide a service. By adopting such a configuration and executing the handover process below the transport layer, the object of the present invention can be achieved.

  ADVANTAGE OF THE INVENTION According to this invention, in the portable terminal device which can utilize a some network, the method of implement | achieving a handover, without sacrificing application development efficiency and portability can be provided.

  That is, according to the present invention, since the API of the transport layer is hooked and the processing necessary for the handover is performed therein, the automatic handover process is performed without changing the application or the middle protocol common protocol higher than the transport layer. Can be realized.

  The present invention provides a portable terminal device that can use a plurality of networks (wireless LAN, cellular phone network, etc.) while an application is executing some service (browser, mail, IP phone, etc.) using a certain network The present invention relates to a system and method for automatically changing (handover) a network to be used to another network without disconnecting the service when the other network becomes available.

  Now, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  Referring to FIG. 1, in the best mode of the present invention, an application 1, a transport layer API hook module 2 that hooks an API of a transport layer called from the application, and control of handover are provided inside the portable terminal device. And a communication module 5 that provides a communication function lower than the transport layer.

  The protocol processing unit 4 includes a SIP processing unit 41 and an HTTP processing unit 42 that execute handover processing specialized for each protocol such as SIP and HTTP above the transport layer, and information necessary for handover of each protocol. SIP storage unit 411, HTTP storage unit 421, and the like.

  The networks A and B represent external networks such as a mobile phone network and a wireless LAN, and the communication module 5 corresponds to the plurality of networks.

  Next, the operation of the best mode for carrying out the present invention will be described in detail with reference to FIG. 1, FIG. 2, and FIG.

  When the application 1 executes the transport layer API when providing a service using the network (see step A-1 in FIG. 2), the transport layer API hook module 2 hooks the execution (step A-2). ) Before calling the original API of the transport layer, the handover manager 3 is called (step A-3).

  The handover manager 3 checks the API argument, identifies the related upper layer protocol (step A-4), and delivers the API to the corresponding processing units 41 to 43 of the protocol processing unit 4 (step A). -5).

  If there is a case where the protocol cannot be determined from the API argument, the protocol is determined by a method such as notifying the protocol used by the handover manager 3 from the application 1 in advance.

  Next, the protocol processing unit 4 stores information necessary for handover from an API argument passed from the handover manager 3 in accordance with the specifications of each protocol such as SIP and HTTP (step A-6). . Thereafter, the transport layer API hook module 2 executes the original transport layer API (step A-7).

  Next, an operation when a handover request is issued from the application 1 or the communication module 5 to the handover manager 3 will be described.

  When the handover manager 3 receives the handover request (see step B-1 in FIG. 3), the API calls from the application are blocked until the handover process is completed for the transport layer API hook module. (Step B-2). Thereafter, the handover manager 3 issues a handover request to the handover target protocol processing units 41 to 43 among the processing units of the protocol processing unit 4 (step B-3).

  The protocol processing units 41 to 43 obtain information necessary for the handover process from the corresponding storage units 411 to 431 (step B-4), and use the function of the communication module 5 for the handover process defined by each protocol. (Step B-5).

  When the handover process is completed, the protocol processing units 41 to 43 notify the handover manager 3 (step B-6), and the handover manager 3 releases the API block to the transport layer API hook module 2. Is requested (step B-7).

  Next, an embodiment of the present invention will be described with reference to FIGS.

  This embodiment includes an IP telephone service using SIP as a service to be handed over, and a mobile telephone network and a wireless LAN as available networks.

  First, referring to FIG. 4, transmission / reception of a general SIP message when establishing an IP telephone session will be described.

  Here, it is assumed that the application 1 transmits and receives a SIP message using the network of the mobile phone network, and the SIP message reaches the communication partner via the SIP server.

  When the application 1 makes an IP phone call to the communication partner, first, the application 1 issues a SIP INVITE to the communication partner (see step C1 in FIG. 4).

  This INVITE includes the SIP address of the communication partner, the IP address of the network used by the application 1 used for subsequent transmission / reception of voice data, the port number, and the like.

  This INVITE is transmitted to the SIP server using the mobile phone network (step C2).

  When receiving the INVITE, the SIP server returns Trying to the application 1 (steps C3 and C4) and transmits the received INVITE to the communication partner (step C5).

  The communication partner notifies the user of the incoming call and returns Ringing to the calling application 1 (steps C6, C7, C8). Thereafter, when the user of the communication partner permits the incoming call, the communication partner returns OK to the application 1 (steps C9, C10, C11).

  This OK includes the IP address and port number of the communication partner.

  Upon receiving OK, the application 1 transmits ACK to the communication partner (steps C12 and C13), thereby establishing an IP telephone session.

  Thereafter, the application 1 and the communication partner transmit and receive voice data using the IP address and port number exchanged by INVITE and OK (step C14).

  Next, the handover operation in the present invention will be described.

  Here, a case will be described in which the network used by the IP phone is handed over to the wireless LAN after the application 1 establishes the IP phone session with the communication partner using the mobile phone network.

  First, referring to FIG. 5, transmission / reception of a SIP message at the time of handover will be described.

  The exchange of SIP messages in steps D1 to D14 in FIG. 5 until the IP telephone session is established is the same as in steps C1 to C14 in FIG. 4, but in this example, an API for transmitting and receiving these messages is hooked. The difference is that information necessary for a later handover is stored.

  When the wireless LAN becomes available after the session is established and the IP telephone service is handed over, the handover manager 3 issues re-INVITE to the communication partner using the data stored in advance. At this time, the IP address and port number of the wireless LAN 5 used after the handover are included by the method defined by the SIP protocol (steps D15 and D16).

  When receiving the re-INVITE, the partner terminal returns OK to the handover manager 3 (steps D17 and D18). When the handover manager 3 receives OK, the partner terminal transmits an ACK to the communication partner (steps D19 and D20). .

  Thereafter, the application 1 starts a call with the communication partner using the wireless LAN (step D21).

  In this example, the operation of each module in FIG. 1 is the same as that described with reference to FIGS.

  In this embodiment, only the case where OK is returned from the communication partner is described. However, when other responses are returned, the handover manager 3 basically follows the operation defined by the SIP protocol. And

  When an error is finally returned, an operation such as notifying the application 1 that the handover has failed, or continuing to use the mobile phone network as it is without any notification is conceivable.

  According to the present invention, in a mobile terminal device that can use a plurality of networks, each network used by a service such as an IP phone, a browser, or an e-mail can be used without significantly degrading application development efficiency, portability, and user convenience. And can be changed dynamically.

It is a block diagram which shows the structure of the best form for implementing this invention. It is a flowchart which shows operation | movement of the best form of this invention. It is a flowchart which shows operation | movement of the best form of this invention. It is a general sequence diagram at the time of establishing an IP telephone session. It is a sequence diagram which shows operation | movement of the best form for implementing this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Application 2 Transport layer API hook module 3 Handover manager 4 Protocol processing part 5 Communication module 41 SIP processing part 42 HTTP processing part 43 FTP processing part 411 SIP storage part 421 HTTP storage part 431 FTP storage part

Claims (8)

  An automatic handover method comprising performing a handover process at a transport layer level.   An automatic handover system using the automatic handover method according to claim 1.   A handover manager that extracts and stores information necessary for hand-over from information obtained by hooking an API of a transport layer, and a protocol processing unit for each protocol to be handed over are provided. Automatic handover method.   An automatic handover system using the automatic handover method according to claim 3.   An automatic handover method, wherein handover processing is executed using information stored by the automatic handover method according to claim 3 at the time of handover.   An automatic handover system using the automatic handover method according to claim 5.   A transport layer API hook module that hooks an API of a transport layer that is executed when an application program uses a network, a handover manager that is called from the transport API hook module and manages a handover process, and an application that provides services And a protocol processing unit that executes processing for each protocol used to provide the automatic handover method.   An automatic handover system using the automatic handover method according to claim 7.

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