JP2002064562A - Method for establishing communication connection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for establishing communication between a server application and a client application by which communication paths or these applications can be switched over without terminating communication between the applications. SOLUTION: This invention provides the communication connection establishing method that is used to control a communication system where proxies relaying communication with applications and a network interconnecting them are provided, and when the applications make communication via a communication path passing through two proxies or more, the 1st proxy placed on the communication path switches a 2nd proxy being a connection destination to a 3rd proxy so as to continue the communication in response to a prescribed switching request.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication connection establishing method used for switching communication paths when a plurality of terminals connected on a network communicate with each other by a server application and a client application.

[0002]

2. Description of the Related Art When a user stops using a communication application and tries to communicate with another application, it is necessary to interrupt communication and then resume communication with another application. However,
In this case, the communication is disconnected, and it is necessary to restart the communication procedure with the application of the other party from the beginning. That is, it is not possible to switch the communication service for a certain application to another application halfway.

For example, mobile terminals such as notebook personal computers and PDAs are portable and can be used in various places, and may be used while moving. When such a mobile terminal is used online, for example, Ethernet (registered trademark), private wireless LAN
(Local Area Network), public wireless communication (for example, PHS
(Personal Handy-phone System)) and the like, and it is necessary to connect the mobile terminal to the network using a communication adapter.

In various places where a mobile terminal is used, it is possible to connect the mobile terminal to a network using one or more communication media. If a plurality of communication adapters corresponding to a plurality of types of communication media are installed in advance, one mobile terminal can be connected to a network at various places by switching the communication method as needed.

When a plurality of terminals actually communicate with each other by a server application and a client application, first, the hardware of the terminal is connected to a network, and a service is provided between the server application providing the service and the client application using the service. It is necessary to establish a communication connection. In addition, in order to enable continuation of communication even when communication is temporarily interrupted due to, for example, a failure, a communication path is constructed so that a relay device called a proxy is interposed between the server application and the client application. Is common.

[0006]

In the conventional communication system as described above, a communication path is determined when communication between a server application and a client application is started. Therefore, the combination of the server application, the client application, and the proxy to be used cannot be changed during the communication.

When changing the server application, the client application, or the proxy, it is necessary to terminate the communication once, release the communication connection, and reconnect each communication connection between the server application and the client application. However, when the mobile terminal communicates while moving, the positional relationship between the server application, the client application, and the proxy changes as the mobile terminal moves, so that a redundant communication path may be formed. For example, there is a case where communication is continued by relaying unnecessary proxies.

Further, for example, when a failure occurs in a terminal under communication, the communication is temporarily terminated, the communication connection is released, and the application or proxy function of the failed terminal is replaced with another terminal. It is necessary to reconstruct the communication path and restart communication from the beginning. In addition, for example, when the user wants to switch the terminal to be used from a mobile terminal having a small screen to a fixed terminal having a large screen (for example, a desktop personal computer), the communication of the mobile terminal is terminated,
It is necessary to release the communication connection, construct a new communication path using the fixed terminal, and restart communication from the beginning.

Accordingly, an object of the present invention is to enable switching between applications and communication paths without terminating communication between a server application and a client application.

[0010]

A first aspect of the present invention is a communication connection establishing method used for controlling a communication system provided with a plurality of applications, a plurality of proxies for relaying communication, and a network connecting them. hand,
In a case where a plurality of applications are communicating with each other via a communication path passing through two or more proxies, in response to a predetermined switching request, the first proxy arranged on the communication path is connected to the first proxy of the connection destination. The second proxy is switched to the third proxy to continue communication.

In the first aspect, when it is necessary to switch the communication path, the connection destination of the first proxy is changed from the second proxy to the third proxy by the control of the first proxy.
Switch to proxy. Therefore, after switching, communication can be continued without using the second proxy. In addition,
The third proxy to be switched to must be specified at the time of switching or must be determined in advance.

[0012] Claim 2 includes a plurality of applications,
A communication connection establishment method used for controlling a communication system provided with a plurality of proxies for relaying communication and a network connecting them, wherein a first application and a second application establish two or more proxies. When communicating with each other via a communication path
A second proxy, which is located on the communication path and relays between the first application and the first proxy, responds to a predetermined switching request by switching the first application of the communication partner to another third application. It is characterized by switching to an application and continuing communication.

According to the second aspect, when it is necessary to switch the application to be used, the application that communicates with the second proxy is controlled by the second proxy from the first application to the third application. The application is switched to and the communication is continued as it is. Therefore, the user can switch the application used for communication without disconnecting the communication.
The third application to be switched needs to be specified at the time of switching or to be determined in advance.

According to a third aspect of the present invention, in the communication connection establishing method according to the first aspect, when the client application and the server application communicate via a plurality of proxies, a response from the server application to a connection request of the client application is received. When transferred to a client application, the transfer path is managed as a session, and a session ID is assigned to each session. When the first proxy receives a switching request for service transfer, the first proxy performs communication. The relay of the third
Connect to the proxy, and then resume relaying,
Launches a new client application using an argument including the corresponding session ID, and the launched new client application connects to the third proxy and transmits information including the specified session ID to the third proxy. The third proxy transmits data to the third proxy by linking the communication of the first proxy and the communication of the new client application based on a session ID. .

In the third aspect, a plurality of sessions are distinguished from each other by using a session ID. Also,
Under the control of the first proxy, the connection destination of the first proxy is switched to the third proxy at the destination. Further, a new client application is automatically started under the control of the third proxy, and the communication of the new client application and the communication of the first proxy are automatically linked.

Therefore, the communication service providing destination of the server application can be moved from the original client application to the new client application without disconnecting the communication. In addition, continuity of communication service can be ensured. According to a fourth aspect, in the communication connection establishing method according to the second aspect, when the client application and the server application communicate via a plurality of proxies, a response from the server application to a connection request of the client application is transmitted to the client application. When transferred, the transfer path is managed as a session, and a session ID is assigned to each session. When the second proxy receives a switching request for service transfer, it relays the communication. The new client application is started by using the argument including the corresponding session ID after the interruption, and the started new client application connects to the second proxy and retrieves the information including the specified session ID. Transmitted to the second proxy, the second proxy,
The relay of the data is resumed by linking the communication of the proxy having a communication path with the server application and the communication of the new client application based on the session ID.

In the present invention, a plurality of sessions are distinguished by using a session ID. Also,
When a request occurs, a new client application is automatically started under the control of the second proxy. Further, a communication path is formed between the newly activated client application and the second proxy under the control of the newly activated client application. Further, under the control of the second proxy, the path of the communication service is switched so that communication is performed between the server application and the started new client application using the corresponding session.

Therefore, the communication service providing destination of the server application can be moved from the original client application to a new client application without disconnecting the communication. In addition, continuity of communication service can be ensured. A communication connection establishing method according to claim 5, wherein a terminal including a client application for requesting a service, a terminal including a server application for providing a service, and a terminal including a proxy for storing and relaying communication contents are connected. A communication connection establishment method used for controlling a system, wherein first information indicating a client application or a server application and a proxy existing in each terminal and second information used for specifying each terminal are stored. In addition, a communication path between a server application and a client application formed by relaying one or more proxies is managed as a session, and at least a session identifier,
Third information for specifying a client application and a server application using the session, fourth information for specifying a proxy used by the session, and a fourth information indicating a connection point of the proxy used by the session. In the case where it is necessary to switch the terminal that provides the server application or the client application to be used and retains the information of No. 5 or to switch the proxy on the communication path used for the communication between the server application and the client application, Utilizing the corresponding session information and the first information and the second information, between the server application and the proxy connected thereto, between the client application and the proxy connected thereto, and between the server application and the client. Wherein the automatic switching at least one communication connection between multiple proxy for relaying between the application.

In the present invention, a communication path between the server application and the client application is managed as a session, and for each session, a session identifier, a client application and a server application that use the session are specified. No. 3 information, fourth information for specifying the proxy used by the session, and fifth information indicating the connection point of the proxy used by the session.
Also, it holds first information indicating a client application or a server application and a proxy existing in each terminal, and second information used for specifying each terminal.

By referring to the first information, it is possible to check the client application, server application, and proxy existing in each terminal. Therefore, for example, when switching between the client application and the server application, it is possible to automatically detect a terminal where the same application exists.

Further, by referring to the second information, it is possible to specify the address of each terminal and the like. Furthermore, the client application, the server application, and the proxy being used can be specified and the connection point of the proxy can be detected from the information of each session distinguished by the session identifier. Can switch from one proxy to another.

In this case, the switching is automatically performed.
The communication path can be switched during the communication without terminating the communication. The contents of the communication during the switching are accumulated in the proxy as necessary, and the proxy performs a relay operation so that the communication is continued after the switching is completed. For this reason, for example, when a failure occurs in the terminal (switch source) including the server application being used, the session configuration is changed so as to switch to another terminal (switch destination) including the same server application, The communication can be continued as it is using the switching destination terminal. Even when such switching is performed, continuity of the communication service is guaranteed.

Similarly, the client application can be switched, and the number of proxies constituting a session and the relay route can be changed. Claim 6
The method according to claim 5, wherein at least one mobile terminal provided with a proxy and a server application or a client application on the same terminal is used as a terminal of the communication system, and the mobile terminal The change of the second information accompanying the switching of the communication device used for communication is absorbed by a proxy arranged on the same mobile terminal.

According to the sixth aspect, since the proxy and the server application or the client application exist on the same terminal to be used, even if the address of the terminal changes due to the movement of the terminal, it is possible to use the same. On the terminal, there is no need to change the communication connection between the server application or the client application and the proxy.

Therefore, when another communication connection is switched, the communication content is held by the storage function of the proxy, so that communication can be continued after the communication connection is switched. According to a seventh aspect of the present invention, in the communication connection establishing method according to the fifth aspect, a session management unit for managing the information of the session exists, and a first proxy, which is a relay actually relaying a certain session, is different from another proxy. When a switch request to the second proxy is generated, any one terminal notifies the switch request to the session management unit, and the session management unit switches to the switch destination second proxy. When a notification indicating that the switching preparation is completed is received from the second proxy to the session management unit, a communication connection with the first proxy is established. A switch request is transmitted from the session management unit to the second proxy together with information on the second proxy to be switched to, and the third proxy Establishes a new communication connection with the second proxy at the switching destination using the session identifier, and performs communication via the communication connection between the first proxy and the third proxy. Is switched to pass through the communication connection between the third proxy and the second proxy, and when the switching of all communication connections is completed, the switching completion is notified to the session management unit, and the switching destination The second proxy establishes a connection between the second proxy and the server application or the client application based on the notified session identifier when the establishment of the first communication connection with the third proxy is completed. Switching the communication path of the session by associating the second communication connection established with the first communication connection with the first communication connection And it features.

According to the seventh aspect, the switching from the first proxy to the second proxy can be automatically performed for one session. Thereby, the function (service) of the application connected to the first proxy can be moved to the application connected to the second proxy. According to a eighth aspect, in the communication connection establishment method according to the fifth aspect, a session management unit that manages the information of the session exists.
When a request for adding a proxy for adding a new third proxy occurs between the first proxy and the second proxy that are actually relaying communication, any one of the additional requests is sent. One terminal notifies the session management unit,
The session management unit inquires of the third proxy added about the additional preparation status,
When the session management unit receives a notification indicating preparation completion from the proxy, the session management unit transmits an addition request to each of the first proxy and the second proxy, and Each of the second proxies establishes a new first communication connection or a second communication connection with the third proxy using the session identifier in response to the addition request, The communication relayed by the proxy and the second proxy is the first
When the switching of the communication connection to be used for all communications is completed, the switching is notified to the session management unit, and the first proxy is communicated with the first proxy. Third
When both the first communication connection with the proxy and the second communication connection between the second proxy and the third proxy are established, the second communication connection is established based on the notified session identifier. The first communication connection and the second communication connection are associated with each other.

According to the present invention, the first proxy and the second proxy that are actually relaying communication for one session are provided.
A new third proxy can be added to the third proxy. In addition, since the state of the proxy at the switching destination is checked before switching, the switching can be executed for the proxy that can be switched reliably. Also,
Since the completion notification is performed after the switching, the switching source proxy can release the resources that have been used until then after the switching.

According to a ninth aspect of the present invention, there is provided the communication connection establishing method according to the fifth aspect, wherein a session management unit for managing the information of the session exists, and for a certain session, the deletion related to the first proxy that is actually relaying communication. When a request occurs, one of the terminals notifies the session management unit of the deletion request, and the session management unit communicates with the first proxy through a first communication connection and a second communication connection. Sending a delete request to each of the second and third proxies establishing a third communication connection between them, the second proxy and the third proxy establishing a third communication connection between them, Switching the communication using the first communication connection and the second communication connection to the third communication connection, and switching the communication connection If completed, the second proxy, and the third proxy and notifies the completion of switching to each said session management unit.

According to the ninth aspect, for one session, the first proxy that is actually relaying communication can be excluded from the session. For example, the first
If removing the proxy will shorten the communication path,
When the first proxy becomes unnecessary, the first proxy can be deleted to optimize the communication path. Even if the first proxy is deleted during the communication, the continuity of the communication service is guaranteed by the control sequence of claim 9 and the operation of the other proxies.

According to a tenth aspect of the present invention, in the communication connection establishing method of the fifth aspect, a session management unit for managing the information of the session exists.
A first communication connection is established between the first proxy and the second proxy, a second communication connection is established between the second proxy and the third proxy, and the first communication connection and A request for replacement from the second proxy to a new fourth proxy in a state where communication is performed using the second communication connection and relaying the first proxy, the second proxy, and the third proxy. Occurs, any one of the terminals notifies the session management unit of the replacement request, and the session management unit makes an inquiry about preparation for replacement to the fourth proxy,
When the session management unit receives a notification indicating the completion of preparation from the fourth proxy, the session management unit transmits a switching request to the first proxy and the third proxy, and transmits the switching request to the first proxy and the third proxy. Each of the third proxies establishes a third communication connection and a fourth communication connection with the replacement fourth proxy based on the session identifier in response to the switching request, Each of the proxy and the third proxy switches the communication performed via the first communication connection and the second communication connection so as to pass through the third communication connection and the fourth communication connection. After the switching of the communication connection used for communication is completed for all communication connections, each of the first proxy and the third proxy is After the completion of switching is notified to the session management unit, and after the third communication connection and the fourth communication connection are established, the third communication connection and the fourth communication are performed based on the notified session identifier. It is characterized by associating with a connection.

In a tenth aspect, for one session, a new fourth session is transmitted from the second proxy in a state where communication is performed via the first proxy, the second proxy, and the third proxy. A proxy can be substituted. For example, when the communication path becomes shorter when the second proxy is replaced with the fourth proxy, the communication path can be optimized by performing the replacement.

Even when the replacement is performed during the communication, the continuity of the communication service is guaranteed by the control sequence and the function of the proxy. It should be noted that the network to which the present invention is applied may take various forms as shown in FIG. The applications 1 and 3 communicating with each other establish a communication path via the proxy 2. The proxy 2 relays communication.

In FIG. 21A, a communication path is established between two applications 1 and 3 with one proxy 2 interposed. Also, in FIG. 21B, two proxies 2 (1), 2
A communication path is established via (2).

The applications 1 and 3 and the proxy 2
In reality, it exists as a process inside a communication node such as a computer (hereinafter, referred to as a node). Various forms can be considered for the arrangement and configuration of the nodes. FIG.
1 (c), application 1 and proxy 2
(1) is located on the same node 4 (1) and proxy 2
(2) is located on node 4 (2), and application 3 is located on node 4 (3).

As shown in FIG. 21C, each node can be equipped with a proxy, an application, or both. Communication between the plurality of applications is performed via at least one proxy. In addition, by interposing a plurality of proxies between a plurality of applications that communicate with each other, it is possible to absorb a disconnection of communication or a change in a communication medium that occurs between the proxies, and the node can be moved. .

Also, by changing the connection relationship between proxies and applications on the communication path, it becomes possible to move network services across nodes. Claim 1 is characterized in that the proxy relation is changed. Claim 2 is characterized in that the application clerk is changed. By changing the cascading relationship in various ways, nodes and applications used for communication can be freely changed, and user convenience can be improved.

For example, when the user is indoors, the service is received by a large-screen node using a wired broadband line, and when the user moves outdoors, the service is transferred to the node of the portable terminal. The communication environment can be adapted to give priority to mobility over quality of communication.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) One embodiment of a communication connection establishing method according to the present invention will be described with reference to FIGS. This embodiment corresponds to claims 1, 2, and 5 to 10.

FIG. 1 is a sequence diagram showing a control sequence when switching between a proxy and an application. FIG. 2 is a block diagram illustrating an example of a communication path when switching between a proxy and an application. FIG. 3 is a sequence diagram showing a control sequence when a proxy is added to a session. FIG. 4 is a block diagram illustrating an example of a communication path when a proxy is added to a session.

FIG. 5 is a sequence diagram showing a control sequence when a proxy is deleted from a session. FIG.
FIG. 4 is a block diagram illustrating an example of a communication path when a proxy is deleted from a session. FIG. 7 is a sequence diagram showing a control sequence when a proxy on a session is replaced. FIG. 8 is a block diagram illustrating an example of a communication path when a proxy on a session is replaced.

FIG. 9 is a block diagram showing a configuration example of a communication system. FIG. 10 is a block diagram illustrating a configuration example of a mobile terminal. FIG. 11 is a schematic diagram illustrating an example of information held by the service management unit SR. FIG. 12 is a schematic diagram illustrating an example of information held by the position management unit LR. FIG. 13 is a schematic diagram illustrating an example of information held by the session management unit SM.
FIG. 14 is a block diagram illustrating a configuration example of a communication system. FIG. 15 is a block diagram illustrating a configuration example of a network. FIG. 16 is a block diagram showing a movement model of nodes and services. FIG. 17 is a sequence diagram showing a procedure for updating location information when the terminal moves.

In this embodiment, the first information in claim 5 corresponds to B11 to B13 and C11 to C13 in FIG. 11, and the second information corresponds to E10 and E12 in FIG. Also,
The session identifier according to claim 5 corresponds to G11 in FIG. 13, the third information corresponds to G12 to G15 in FIG. 13, the fourth information corresponds to G16 in FIG. 13, and the fifth information corresponds to FIG. 1
3 corresponds to G17.

In this embodiment, it is assumed that the present invention is applied to a communication system as shown in FIG. In the example of FIG. 9, three types of sub-networks 51, 52, 5
3 are connected to each other via a wide area network 54. In the sub-network 51, via a communication interface configured according to the Ethernet standard,
Many terminals (55, 56) can be connected in a communicable state by wire.

The sub-network 52 constitutes a wireless LAN. The mobile terminals 59 and 60 having a wireless communication interface conforming to this standard can perform wireless communication with the base stations 57 and 58 and wirelessly communicate with the sub-network 5.
2 is connected. Of course, communication with the base stations 57 and 58 cannot be performed outside the specific communicable area. The subnetwork 53 is a network of a PHS which is a public wireless communication system. In the example of FIG. 9, the sub-network 53 includes a mobile terminal 61, a fixed terminal 62, and a TAP (PIAFS).
TAP 63 is connected to base stations 64 and 65. The mobile terminals 66 and 67 having a wireless communication interface configured according to the PHS communication standard can perform wireless communication with the base stations 64 and 65. Of course, communication with the base stations 64 and 65 cannot be performed outside the specific communicable area.

For example, when the mobile terminal 59 shown in FIG. 9 moves near the mobile terminal 55, the mobile terminal 59 may not be able to perform wireless communication with the base station 57. However, at that position, the mobile terminal 59 can be connected to the sub-network 51 by wire. In the case of a general system, when a terminal switches a network used for communication among the sub-networks 51, 52, and 53, it is necessary to temporarily end application communication and reconstruct a communication path. It takes time and effort.

In practicing the present invention, the network used by the terminal for communication is connected to the sub-network 51,
Even when switching between 52 and 53, the switching can be performed automatically without terminating the communication of the application. Further, for example, when the same application program exists in the mobile terminal 55 and the fixed terminal 56, while one user is communicating using the application program on the mobile terminal 55, It is also possible to switch to a program for continuous communication.

Each terminal (mobile terminal in this example) used to carry out the present invention is configured as shown in FIG. The mobile terminal of FIG. 10 includes an Ethernet communication adapter 21 to enable connection with the sub-network 51,
The wireless LAN adapter 22 is provided to enable connection to the sub-network 52, and the PHS communication adapter 23 is provided to enable connection to the sub-network 53.

The mobile terminal shown in FIG.
0, server application 11, client application 12, proxy 13, agent 1
4, a link switching unit 15, links 16, 17, 18, a position management unit LR, a session management unit SM, and a service management unit SR. The server application 11 is a program for providing a service of a specific application. The client application 12
This is a program for using the service provided by the server for a specific application.

The proxy 13 relays communication from a certain transmission source to a certain reception destination and stores the contents of the communication in its own storage device. For example, temporarily proxy 13
Even if communication between the recipient and the recipient becomes unavailable,
Since the content of the communication input from the transmission source to the proxy 13 is stored in the proxy 13, when the communication between the proxy 13 and the reception destination is restored, the information stored in the proxy 13 is transmitted to the reception destination. Communication can be continued.

The proxy 13 in FIG. 10 can relay the communication of the server application 11 or the communication of the client application 12. Link switching unit 15
Are links 16, 17, which are used for communication with other terminals,
Switch 18. The link 16 is connected to an Ethernet communication adapter 21, the link 17 is connected to a wireless LAN adapter 22, and the link 18 is a PHS communication adapter 23.
Is connected to

When communication is performed using the link 16 and the Ethernet communication adapter 21, the sub-network 5
1 and can communicate over link 17 and wireless L
When communication is performed via the AN adapter 22, communication can be performed via the sub-network 52 and the link 18
When using the PHS communication adapter 23, the communication can be performed via the sub-network 53.

That is, by switching the links 16, 17, and 18 used by the link switching unit 15, the communication system can be switched to connect to any of the sub-networks 51, 52, and 53. Each terminal that communicates has
Each is assigned an IP (Internet Protocol) address. Also, when the terminal switches the communication method,
Since the terminal moves on the network beyond the boundary of the subnet, which is the unit of address allocation, a new address is used each time switching is performed.

The service management unit SR manages information on the types and functions of the server application 11, client application 12, and proxy 13 provided in each terminal. Actually, for example, the contents shown in FIG. 11 are held in the service management unit SR. In the example of FIG.
11 is a server B11 as an application program
And a proxy C11 is provided. Terminal A
Reference numeral 12 denotes a server B12 as an application program.
And a proxy C12 is provided. Further, terminal A
Reference numeral 13 holds a client B13 as an application program and includes a proxy C13.

The location management unit LR manages an IP address for each terminal. The location management unit LR can manage the IP addresses of a large number of terminals as well as the terminals having the same. However, in order to improve the efficiency of location management and to enable location management even for terminals with few resources, management of the amount of movement of the terminals and the storable capacity related to location management is also performed. Furthermore, in order to limit the range of terminals to be managed, a plurality of terminals are divided and managed in groups.

In practice, as shown in FIG. 12, for example, the terminal identification name E10, group name E11, and IP address E
12, the state (usability) of each IP address E13, the movement amount E14, the storage capacity of the LR, and the information of the update time are held for each terminal of a specific group managed. Further, when a communication device is switched due to movement of a terminal or the like, the IP address of the terminal changes. In this case, the content held by the location management unit LR is updated. At the same time, if there is a communication partner, an update instruction of the position information is transmitted to the communication partner. That is, the update procedure shown in FIG. 17 is executed.

When each terminal transmits a position information update instruction, the order in which the instructions are transmitted is determined in consideration of a predetermined priority. For example, a terminal having a small amount of movement, such as a fixed terminal (such as a desktop personal computer) 56, is given a high priority. Also, a high priority is given to a terminal having a large storage capacity (E15) of position information.

Each group used for the management of the location management unit LR can include a plurality of terminals existing in a range beyond the boundary of the subnet. Also, a plurality of groups can coexist in one subnet.

The terminal (X1) that intends to newly join the group acquires its IP address and broadcasts a group search request in the sub-network,
Alternatively, a group search request is transmitted to a known specific terminal (X2). Thereafter, when the terminal (X1) receives a response from the terminal (X2) that has received the group search request,
The group information is acquired from the contents, and the group to be joined is selected.

The terminal (X1) transmits a registration request to the selected group to the terminal (X2). Terminal (X
2) obtains the position information of the terminal (X1) that has transmitted the registration request. Further, the terminal (X2) that has received the registration request transmits the information of the location management unit LR included therein to the terminal (X1), and adds the location information of the subscribed terminal (X1) to the content of the location management unit LR. Completes the procedure for joining the group.

When searching for location information on each terminal, the location information is searched for from information held by the location management unit LR included in the terminal itself. If the search is not successful, a search request is sent to any terminal included in the information held by the location management unit LR. When a result is returned in response to the search request, the position information is added to the position management unit LR.

When searching for a terminal belonging to the same group in the subnet, a broadcast packet is transmitted, and location information is registered in the location management unit LR based on a response to the broadcast packet. The position management unit LR includes the following functions. (1) Change of IP address due to movement of terminal position, etc. (2) Change of IP address state due to node disconnection, line disconnection, failure, etc. (3) Notification of change to agent 14 (4) Participation in group (5) Transmission / reception of position information with the position management unit LR of a node in the group The session management unit SM in FIG. 10 manages the entire communication path of each communication as a session.
For example, in FIG. 15, communication can be performed between the application 101 and the application 102 using the session 103. In this case, session 10
3 includes proxies 104, 105, and 106.

The session 103 uses the communication connections 107, 108, 109, 110. The communication connection 107 is a communication path established between the application 102 and the proxy 104. The communication connection 108 is a communication path established between the proxies 104 and 105. The communication connection 109 is a communication path established between the proxies 105 and 106. The communication connection 110 is a communication path established between the application 101 and the proxy 106.

The actual session management section SM holds information G11 to G18 as shown in FIG. 13, for example.
Information G11 is an identifier for distinguishing a plurality of sessions. The information G12 indicates the name of the node (terminal) where the server application to be used exists. Information G1
3 represents a port number given to the server application to be used.

The information G14 indicates the name of the node where the client application to be used exists. The information G15 indicates a port number given to the client application to be used. Information G16 represents the name of the node where the proxy to be used exists. Information G17 is
Indicates the port number assigned to the proxy to be used. When the communication path of one session is configured to relay a plurality of proxies, each node name and port number of the plurality of proxies to be used and the connection status of the plurality of proxies are one session ID (G11 ) Is held in the session management unit SM.

The functions performed by the session management unit SM include adding a proxy to each session, deleting a proxy, switching proxies, and communicating with the session management unit SM existing in another terminal. The agent 14 in FIG. 10 includes a location management unit LR, a session management unit SM,
It mediates various information held by the service management unit SR, and determines the proxy 13 by comprehensive judgment of the information.
And the link switching unit 15.

For example, when it is desired to terminate a server application that is currently providing a predetermined communication service while continuing the service, the service management unit S may execute a substitute server application of the same type.
The search can be performed using R. Also, the location management unit L
Since the identification name of the terminal and its IP address are held in R, the position of the terminal where the server application to be switched exists can be specified. Further, the session management unit SM
By performing the processing described later using the information of the specific session managed by the server, the server application can be switched and the communication service can be continued.

The agent 14 instructs the link switching unit 15 to switch the link, and after the link is switched,
Request the proxy to restart the communication connection. The link switching unit 15 has functions such as connection to a new link, disconnection of a link, and routing management. Also,
The proxy has a function of hiding the disconnection or change of the link under the connection (see FIG. 16).

When a service is moved from a certain source to a certain destination, the session used in the communication of the service starts with the service of the source or the service built on the proxy. Can be realized by transferring the state of The state of the service to be transferred includes the connection state of the application and the proxy constituting the session, the number of bytes of transmitted / received data, the number of frames, and the like.

For example, when a portable mobile terminal is used to receive and view stream data from a specific server application via a wireless line and a network, a high quality service is provided because the terminal has low display capability. I can't get it. However, if the user moves the service from the mobile terminal to the fixed terminal having a large screen, high quality service can be received. Even in the case of such a movement, the service can be continuously used.

When the same server application exists in a plurality of terminals, the communication path used for providing the service can be switched so as to switch the terminal and the application on the server side. The communication speed of the service can be improved by switching the terminals. Specific examples of switching communication paths used for providing services and switching between server applications or client applications will be described below. Here, a communication system as shown in FIG. 14 is assumed.

In FIG. 14, mobile terminals 30 (1) to 30 (1) to 30
Each function of (5) is shown in a simplified manner. Actually, each of the mobile terminals 30 (1) to 30 (5) has the same function as the mobile terminal shown in FIG. However, the server application 11 is provided only on the mobile terminal 30 (1), and the client application 12 is provided on the mobile terminal 30 (1).
It is provided only in (2) and 30 (3). The mobile terminal 30
(5) does not include the session management unit SM. When using the proxy 13 of the mobile terminal 30 (5), the control may be performed using the session management unit SM provided in the mobile terminal 30 other than the mobile terminal 30 (5).

First, the case where the proxy and the application are switched will be described. Specifically, in the state before switching, the communication connection 201 is established between the server application 11 (1) of the mobile terminal 30 (1) and the proxy 13 (1) in FIG. 13 (2), a communication connection 203 is established between the client application 12 (2) and the proxy 13 (2),
Server application 11 (1) -proxy 13 (1) -proxy 13 (2) -client application 12 (2)
It is assumed that a session is formed so as to pass through the communication path of.

Here, instead of the client application 12 (2) on the mobile terminal 30 (2), the mobile terminal 30 (3)
When it is desired to continuously receive the service of the server application 11 (1) using the above client application 12 (3), the function of the session management unit SM (2) is used as shown in FIG. Execute the control sequence. That is, the proxy 13 (2) is switched to the proxy 13 (3).

The agent 14 of the terminal which manages the use state of the user and the connection state between the terminals may transmit the application (A
A switching request P) is generated. This switching request is notified, for example, to the session management unit SM (2). In this case, the session management unit SM (2) executes step S11 in FIG. That is, in order to switch to the switching destination proxy 13 (3) for which the communication connection 204 has been established with the switching destination client application 12 (3), an inquiry regarding the switching is made to the proxy 13 (3). At the time of this inquiry, the session management unit SM (2) also transmits the session ID of the corresponding session and information on the connection status of the proxy as parameters to the proxy 13 (3).

This parameter includes the proxy 1 of the switching source.
3 (2) also includes the file name of the file relaying the transfer and the number of bytes (the current transfer position on the file) at which the transfer has been completed. Proxy 13 that was queried
In (3), necessary processes and the like are started based on the received parameters, and preparations are made for relaying communication in step S12. This proxy 13 (3) inherits the state of the switching source proxy 13 (2) based on the received parameters.

In this preparation, if the required application 12 (3) is not activated, the proxy 13 (3) activates the application 12 (3).
If the communication connection 204 between the application 12 (3) and the proxy 13 (3) has not been established, the communication connection 204 is established. When the preparation is completed, in step S13, the proxy 13 (3) transmits a preparation completion notification to the session management unit SM (2).

When the session management unit SM (2) receives the preparation completion notification, in step S14, the switching source proxy 1
A switching request is transmitted to the proxy 13 (1) that has established the communication connection 202 with the proxy 3 (2). This switching request includes, as a parameter,
Node name (G16) and port number (G1) for (3)
7) is included.

When the proxy 13 (1) receives the switching request, the proxy 13 (3) uses the connection request parameter and the session ID to connect to the connection point of the proxy 13 (3).
The communication connection 205 is established for the P address and the port number of the proxy 13 (3) (S15). When the communication connection 205 is established with the proxy 13 (1), the proxy 13 (3) sets the communication connection 204 and the client application 12 (3) for a specific session determined by the session ID received when the communication connection 205 is established. ) Is associated (S16). Thereby, the communication connection 205 and the communication connection 2
The preparation of the proxy 13 (3) for relaying (accumulating and transferring) the communication with the proxy 04 is completed.

Further, the proxy 13 (1) switches all communication that has been performed through the communication connection 202 to the communication connection 205 (S 17). After this switching is completed, the proxy 13 (1) transmits a switching completion notification to the session management unit SM (2) (S1).
8).

Upon receiving the completion notification, the session management unit SM (2) updates the contents of the managed table (S
19). That is, for a specific session determined by the session ID (the session switched in this process), the node names and port numbers of the switched client application 12 (3) and proxy 13 (3) and their connection relations are reflected. Update the information to do so.

The session management unit SM (2) changes the other session management units SM (1), SM (3), and SM (4) that manage the information of the changed session. The information is notified (S21). As a result of the above control sequence, as shown in FIG. 2, the server application 11 (1)
The service provided by the communication between the client application 12 (2) and the
The contents of the session (communication path) are changed so as to switch to communication between 1 (1) and the client application 12 (3).

Next, a case where a proxy is added to a session will be described. Specifically, before the addition, the communication connection 211 is established between the server application 11 (1) and the proxy 13 (1) as shown in FIG. A communication connection 212 is established between the proxy 13 (2) and the client application 12 (2).
3 is established, and a session is established so that the two proxies 13 (1) and 13 (2) relay the communication between the server application 11 (1) and the client application 12 (2).

From this state, the proxy 13 (3) is placed between the proxy 13 (1) and the proxy 13 (2) while the communication is continued.
Is added, the control sequence shown in FIG. 3 is executed using the function of the session management unit SM (2). The terminal agent 14 generates a proxy addition request as needed (for example, according to a user's instruction). This addition request is notified to, for example, the session management unit SM (2). In this case, the session management unit SM (2) executes step S31 in FIG.

That is, in order to make the proxy 13 (3) to be added prepare for addition, the session management unit SM (2)
Makes an additional query. When making this inquiry,
The session ID of the corresponding session and the information on the connection state of the proxy are also used as parameters in the session
The packet is transmitted from (2) to the proxy 13 (3). This parameter also includes the file name of the file to which the proxy 13 (2) is relaying the transfer and the number of bytes that have completed the transfer (the current transfer position on the file).

The proxy 13 (3) receiving the inquiry,
Based on the received parameters, necessary processes and the like are started, and preparations for relaying communication are made in step S32. The proxy 13 (3) inherits the state of the proxy 13 (2) based on the received parameters. When the preparation is completed, in step S33, the proxy 13 (3) transmits a preparation completion notification to the session management unit SM (2).

When the session management unit SM (2) receives the preparation completion notification, in steps S34 and S35, the proxies 13 (1) and 13 (13) to be connected to the proxy 13 (3) to be added are set.
A switching request is transmitted to (2). This switching request includes:
The node name (G16) and the port number (G17) of the proxy 13 (3) to be added are included as parameters. Upon receiving the switching request, the proxies 13 (1) and 13 (2) receive the connection point (the IP address of the terminal and the proxy 13 (3)) using the parameters of the switching request and the session ID. The communication connection 214 or 215 is established for the port number (S36, S36).
37).

The proxy 13 (3) communicates with the communication connection 21.
When the connection 4, 215 is established, the communication connection 214 and the communication connection 215 are associated with each other for a specific session determined by the session ID received when the connection is established (S38). This completes the preparation of the proxy 13 (3) for relaying (accumulating and transferring) the communication between the communication connection 214 and the communication connection 215.

On the other hand, the proxy 13 (1) switches all the communications that have been performed via the communication connection 212 to the communication connection 214 (S41). After this switching is completed, the proxy 13 (1) transmits a switching completion notification to the session management unit SM (2) (S4).
4). Similarly, the proxy 13 (2) switches all communication that has been performed via the communication connection 212 to the communication connection 215 (S40). After this switching is completed, the proxy 13 (2) sets the session management unit SM
A switching completion notification is transmitted to (2) (S42).

When receiving the completion notification, the session management unit SM (2) updates the contents of the managed table (S
45). That is, for a specific session determined by the session ID (the session in which the proxy was added in the current process), information is reflected so as to reflect the node name and port number of the added proxy 13 (3) and the connection relationship between the proxies. Update.

Further, the session management unit SM (2) changes the other session management units SM (1), SM (3), and SM (4) that manage the information of the changed session. The information is notified (S46). As a result of the above control sequence, as shown in FIG. 4, the server application 11 (1)
Communication between the client application 12 (2) and the proxy 13 (1) -proxy 13 (3) -proxy 13
The contents of the session are changed so as to be relayed on the route (2).

Next, a case where a proxy used so far from a session is deleted will be described. Specifically, before the addition, the communication connection 221 is established between the server application 11 (1) and the proxy 13 (1) as shown in FIG. A communication connection 222 is established between the
A communication connection 223 is established between (3) and 13 (2), and a communication connection 224 is established between the proxy 13 (2) and the client application 12 (2).
A session is established so that the three proxies 13 (1), 13 (3), and 13 (2) relay communication between the server application 11 (1) and the client application 12 (2).

From that state, the proxy 13 (3) between the proxy 13 (1) and the proxy 13 (2) while the communication is continued.
Is deleted (excluded from the session), the control sequence shown in FIG. 5 is executed using the function of the session management unit SM (2). The terminal agent 14 generates a proxy deletion request as needed (for example, according to a user's instruction). This deletion request is notified, for example, to the session management unit SM (2). In this case, the session management unit SM (2) executes the processing in order from step S51 in FIG.

The session management unit SM (2) communicates with the proxy 13 (3) to be deleted by the communication connection 222,2.
A deletion request relating to the proxy 13 (3) is transmitted to each of the proxies 13 (1) and 13 (2) that have established 23 (S51, S52). Upon receiving the deletion request, the proxy 13 (2) establishes a communication connection 225 between the proxy 13 (2) and the proxy 13 (1) using the session ID (S53).

Further, the proxy 13 (2) switches all the communication which has been performed through the communication connection 223 to the communication connection 225 (S54). After this switching is completed, the proxy 13 (2) transmits a switching completion notification to the session management unit SM (2) (S5).
8). The communication connection 223 between the proxy 13 (2) and the proxy 13 (3) is disconnected by the proxy 13 (2) (S56).

Similarly, the proxy 13 (1) switches all the communications that have been performed through the communication connection 222 to the communication connection 225 (S55). After this switching is completed, the proxy 13 (1) transmits a switching completion notification to the session management unit SM (2) (S5).
9). The communication connection 222 between the proxy 13 (1) and the proxy 13 (3) is disconnected by the proxy 13 (1) (S57).

When receiving the completion notification, the session management unit SM (2) updates the contents of the managed table (S
60). That is, for a specific session determined by the session ID (the session in which the proxy was deleted in the current process), the information is updated so that the connection result between the proxies reflects the result of the deletion. Further, the session management unit SM (2) manages the information of the changed session by the other session management units SM (1), SM (3), SM (4).
Is notified of the changed information (S61).

As a result of the above control sequence, the communication between the server application 11 (1) and the client application 12 (2) is established by the proxy 13 as shown in FIG.
(1) The content of the session is changed so as to be relayed on the route of the proxy 13 (2). Next, a case where a proxy used in a specific session is replaced with another proxy will be described. Specifically, in the state before addition, FIG.
As shown in the figure, a communication connection 231 is established between the server application 11 (1) and the proxy 13 (1), a communication connection 232 is established between the proxies 13 (1) and 13 (4), and the proxy 13 ( A communication connection 233 is established between 4) and 13 (2), a communication connection 234 is established between the proxy 13 (2) and the client application 12 (2), and the three proxies 13
(1), 13 (4) and 13 (2) are server applications 11
A session is established to relay the communication between (1) and the client application 12 (2).

In this state, when replacing the proxy 13 (4) used while continuing communication with the proxy 13 (5), the function of the session management unit SM (2) is used.
The control sequence shown in FIG. 7 is executed.

The agent 14 of the terminal issues a proxy replacement request as required (for example, according to a user's instruction). This replacement request is sent to the session management unit SM
(2) is notified. In this case, the session management unit SM (2)
Executes step S71 in FIG. That is, the session management unit SM (2) makes an inquiry about replacement in order to prepare the replacement proxy 13 (5) for relay. At the time of this inquiry, the session ID of the corresponding session and information on the connection state of the proxy are also transmitted as parameters from the session management unit SM (2) to the proxy 13 (5).

This parameter includes the proxy 1 of the replacement source.
3 (4) also includes the file name of the file relaying the transfer and the number of bytes (the current transfer position on the file) at which the transfer has been completed. Proxy 13 that was queried
In (5), necessary processes and the like are started based on the received parameters, and preparations are made for relaying communication in step S72. This proxy 13 (5) inherits the state of the replacement proxy 13 (4) based on the received parameters. When the preparation is completed, in step S73, the proxy 13 (5) transmits a preparation completion notification to the session management unit SM (2).

When the session management unit SM (2) receives the preparation completion notification, in steps S74 and S75, the communication connection 232,2 is established between the session management unit SM (2) and the replacement proxy 13 (4).
The switching request is transmitted to the proxies 13 (1) and 13 (2) that have established the connection 33. This switching request includes, as a parameter, the node name (G1
6) and the port number (G17).

When the proxies 13 (1) and 13 (2) receive the switching request, the proxies 13 (1) and 13 (2)
Using D, a communication connection 235 or 236 is established to the connection point of the proxy 13 (5) (the IP address of the terminal and the port number of the proxy 13 (3)) (S
76, S77).

When the communication connections 235 and 236 are established, the replacement proxy 13 (5) establishes a connection between the communication connection 235 and the communication connection 236 for a specific session determined by the session ID received when the connections are established. Associate (S78). Thereby, the communication connection 235 and the communication connection 23
The preparation of the proxy 13 (5) for relaying (accumulating and transferring) the communication with the proxy 6 is completed.

On the other hand, the proxy 13 (2) switches all the communications that have been performed through the communication connection 233 to the communication connection 236 (S80). After this switching is completed, the proxy 13 (2) transmits a switching completion notification to the session management unit SM (2) (S8).
2). Similarly, the proxy 13 (1) switches all the communications that have been performed via the communication connection 232 to the communication connection 235 (S81). After this switching is completed, the proxy 13 (1) sets the session management unit SM
A switching completion notification is transmitted to (2) (S83).

After the switching from the communication connections 232 and 233 to the communication connections 235 and 236 is completed,
The unnecessary communication connections 232, 233 are disconnected (S84, S85). Session management unit SM (2)
Updates the contents of the managed table upon receiving the completion notification (S86). That is, for a specific session determined by the session ID (the session in which the proxy was replaced in the current process), the information is updated so that the connection result between the proxies reflects the result of the replacement.

The session management unit SM (2) has changed the other session management units SM (1), SM (3) and SM (4) which manage the information of the changed session. The information is notified (S87). As a result of the above control sequence, as shown in FIG. 8, the server application 11 (1)
Communication between the client application 12 (2) and the proxy 13 (1) -proxy 13 (5) -proxy 13
The contents of the session are changed so as to be relayed on the route (2).

[0107] Communication performed between the server application 11 and the client application 12 is assigned a unique session ID that is different for each session. The connection point of the proxy indicates a position on the network and a port for receiving a connection request. When TCP / IP is assumed as the protocol, the connection point is the IP address and the port number on which the proxy is listening.

Further, for example, when a communication connection is switched to switch a communication path of a session, communication is temporarily disabled, but at least one proxy included in the session stores communication contents transmitted by the application. Then, when communication becomes possible, the stored information is transmitted to automatically perform a communication recovery operation. Therefore, even when the communication path is switched during the communication, the communication can be continued without any special operation by the user.

An outline of the function of the present invention can be represented by a movement model shown in FIG. That is, even when the terminal used by the user moves and the communication system is switched, or when the terminal used by the user is switched, the same service can be continuously provided to the same user. The services handled here mean communication contents transmitted and received between applications through each session, communication protocols (such as http) and expression methods (such as reproduction and browsing) associated therewith.

When the service is moved, the service state can be continued in the same state by transferring the state of the service from the source session indicated by the same session ID to the destination session. Each terminal (node) is mapped to a link layer address space as shown in FIG. Therefore, the movement of the node can be realized by changing the correspondence between the node and the address. Also, each terminal can have a plurality of communication devices, each of which can hold a unique address.

In order to evaluate the performance of the position management method in the communication system of the above embodiment, a simulation was performed using a computer. The simulation conditions are as follows. (1) Terminal movement interval: Among many terminals constituting the group, (1/3) has an average movement time of 30 minutes and the remaining
The terminal (2/3) has an average moving time of 10 minutes.

(2) The communication standby time of the terminal is 20 minutes,
The communication time is 50 minutes. (3) Storage capacity of location management unit LR: out of many terminals
The (1/3) LR can hold the location information of all the terminals, the LRs of the other (1/3) terminals can hold the (1/2) terminal location information, and the remaining (1/3) It is assumed that the LR of the terminal () can hold the position information of the terminal (１ ／).

(4) The number of location information update commands issued in 1200 minutes and the search success rate of the location management unit LR are set to 400
Trial measurements were taken. However, the first 100 minutes are excluded from statistics. (5) When transmitting the position information update command, the position management unit LR transmits all the position information held by itself.
The LR on the receiving side updates the positional information that is selectively stored based on the time stamp of the positional information.

(6) Two types of methods are evaluated for the priority of the terminal when issuing the position information update command. "Me
In the method of “thod A”, when the location management unit LR updates the location information held by itself, it issues a location information update command to all terminals. In the method of “Method B”, only the LR of the terminal having a movement interval of 30 minutes and having a storage capacity capable of holding the position information of all terminals issues a position information update command to all terminals, The position management unit LR of the terminal issues a position information update command only to terminals having a movement interval of 30 minutes and a storage capacity capable of holding the position information of all terminals.

In the method of "Method A", a location update command is issued to every terminal every time the location of each terminal is updated, so that the communication amount increases, but excellent location management capability can be obtained. 18 to 2 show the results of the above simulation.
0 is shown. FIG. 18 shows the number of issued position information update instructions. 19 and 20 show the location search success rates. The location search success rate in FIG. 19 is a rate at which the location information of the partner terminal is successfully acquired by searching the location information held by the location management unit LR of the specific terminal and by searching the location management unit LR of another terminal. is there. The position search success rate in FIG. 20 is a rate at which only the position information held by the position management unit LR of the specific terminal is searched and the position information of the partner terminal is successfully obtained.

Referring to FIGS. 18 and 19, "Method
"Method B" has lower communication cost than "A" (6
0 to 80%), and it can be seen that the deterioration of the position search capability is also within an allowable range. This effect is more remarkable as the number of terminals forming the group is larger, and the difference in the location search success rate is smaller. Therefore, by limiting the terminals to which the position information update command is issued in consideration of the movement amount of each terminal and the storage capacity of the position management unit LR, the load of the position management of each terminal is shared and the communication amount is suppressed. can do.

Further, as can be seen from FIG. 20, it is possible to correctly detect 25 to 45% of terminal positions without searching for position information existing in other terminals. Therefore, even when the terminal is temporarily disconnected from the network, it is possible to obtain a clue to reconnect to the network by searching only the position information held by the own position management unit LR. .

(Second Embodiment) Another embodiment of the communication connection establishing method according to the present invention will be described with reference to FIG.
2 and FIG. This embodiment corresponds to claims 1 to 4. FIG. 22 and FIG. 23 are sequence diagrams showing service movement examples (1, 2), respectively.

In this embodiment, since it is assumed that HTTP communication is performed, the browser 5 and the Web server 7 are used as applications. In the example of FIG. 22, since the browsers 5 operating as client applications are arranged at the nodes 8 (A) and 8 (B), the nodes 8 (A) and 8 (B) function as client nodes. In addition, since the Web server 7 operating as a server application is arranged in the node 8 (C), the node 8 (C) functions as a server node.

In the example of FIG. 23, the browsers 5 (A) and 5 (B) operating as client applications are arranged in the node 8 (A).
(A) functions as a client node. Further, since the Web server 7 operating as a server application is arranged in the node 8 (C) in FIG. 23, the node 8 (C) functions as a server node.

The operation of the example shown in FIG. 22 will be described. First, the proxy 5 (A), 6 (B) from the browser 5 (A)
A request is made to the Web server 7 via (C11). The response of the Web server 7 to this request is
The data is transmitted to the browser 5 (A) via (C) and 6 (A) (C12). At this time, a session is established. Also, a session I for distinguishing each session
D is assigned.

Thereafter, the proxy 6 (C) receives the service transfer request (C13). In that case, proxy 6
(C) interrupts the communication (C14), and moves to the destination node 8.
It connects to the proxy 6 (B1) of (B) (C15). In this case, the proxy 6 (B1) of the movement destination activates the browser 5 (B) using the URL including the session ID of the corresponding session as an argument (C16).

The activated browser 5 (B) connects to the proxy 6 (B2) using the URL specified at the time of activation (C17). The proxy 6 (B2) connects the communication of the browser 5 (B) and the proxy 6 (C) of the node 8 (C), which is a server node, to transfer data based on the session ID (C18). In this way, the service moves through the client node while maintaining the continuity of the service.

Next, the operation of the example shown in FIG. 23 will be described. First, the proxy 6 (A), 6 from the browser 5 (A)
Make a request to the Web server 7 via (C) (C2
1). The response from the Web server 7 is transferred to the browser 5 (A) via the proxies 6 (C) and 6 (A) (C22). At this time, a session is established. Also, a session I for distinguishing each session
D is assigned.

Thereafter, the proxy 6 (A) receives the service transfer request (C23). In that case, proxy 6
(A) is a U including the session ID of the corresponding session.
The browser 5 (B) is started using the RL as an argument (C2
4). The activated browser 5 (B) connects to the proxy 6 (B2) using the URL specified at the time of activation (C25). This proxy 6 (B2)
Based on D, the communication of the browser 5 (B) and the proxy 6 (C) of the node 8 (C), which is a server node, are linked to transfer data (C26).

In this way, the service moves from one client node to another while maintaining the continuity of the service. (Third Embodiment) Another embodiment of the present invention will be described with reference to FIGS. This embodiment corresponds to claims 1 and 2.

FIG. 24 is a sequence diagram showing a simplified control sequence when a proxy is added to a session. FIG. 25 is a sequence diagram showing a simplified control sequence when a proxy is deleted from a session. FIG. 26 is a sequence diagram showing a simplified control sequence when a proxy on a session is replaced.

This embodiment is a modification of the first embodiment, and the contents of the control sequence are simpler than those of the first embodiment. Also in this embodiment, it is assumed that a mobile terminal having a configuration as shown in FIG. 10 is used. However, the position management unit LR, service management unit SR, and link switching unit 15 shown in FIG. 10 are not necessarily required.

The contents of the operations shown in FIGS. 24 to 26 are the same as those in the first embodiment, but the contents of the control in each figure will be described below. First, a case where the proxy 13 (3) is added to the session as in the case of FIG. 4 will be described with reference to FIG. In this example, in FIG. 4, a communication connection is established in the order of the client application 12 (2), the proxy 13 (2), the proxy 13 (1), and the server application 11 (1). 11 (1), the client application 1
2 (2), proxy 13 (2), proxy 13 (3),
Proxy 13 (1), server application 11
It is assumed that a communication connection is established in the order of (1) and the path of a session between the client application 12 (2) and the server application 11 (1) is changed.

In other words, the operation for adding another proxy 13 (3) between the proxy 13 (2) and the proxy 13 (1) is shown. The agent software (14 in FIG. 10) controls commands and management related to the connection state between the user or the terminal. The proxy switching request from the agent software is transmitted to the mobile terminal 30.
Upon receiving (2), the mobile terminal 30 (2) notifies the session management unit SM (2) of the reception.

In this case, the session management unit SM (2)
The proxy 13 (1) and 13 (2) connected to the added proxy 13 (3)
A switching request is transmitted using the name and connection point of (3) as parameters (S34, S35). The proxies 13 (1) and 13 (2) that have received the switch request use the received parameters and the session identifier (ID) to perform the proxy 13 (1) and 13 (2).
A communication connection corresponding to the session identifier is established for the connection point (3) (S36, S3).
7).

Thereafter, the proxy 13 (1)
All the communication performed through the communication connection with 3 (2) is switched to the communication connection with the proxy 13 (3) (S40, S41). Proxy 13 (3) to be added
, Two communication connections are established. The proxy 13 (3) associates two communication connections based on the session identifier received at the time of establishing the communication connection, and makes a state in which accumulation and transfer are possible.

Next, a case where the proxy 13 (3) is deleted from the session as in the case of FIG. 6 will be described with reference to FIG. In this example, in FIG. 6, the client application 12 (2), the proxy 13
A communication connection is established in the order of (2), the proxy 13 (3), the proxy 13 (1), and the server application 11 (1).
From the state where a session between (2) and the server application 11 (1) is established, the client application 12 (2), the proxy 13 (2), the proxy 13 (1), and the server application 11 (1) are arranged in this order. A communication connection is established, and the client application 12 (2) and the server application 11
It is assumed that the session route is changed between (1).

That is, from the session to the proxy 13
This represents an operation for deleting (3). The mobile terminal 30 transmits a proxy deletion request from the agent software.
Upon receiving (2), the mobile terminal 30 (2) notifies the session management unit SM (2) of the reception. In this case, the session management unit SM (2) sends the proxy 13 (1), 13
A deletion request is transmitted to (2) (S51, S5
2).

Upon receiving the deletion request, the proxy 13 (2) establishes a connection with the proxy 13 (1) using the session identifier. Also, proxy 13
(3) All communications performed with the proxy 13
Switch to communication connection with (1). Also,
When the proxy 13 (1) receives the deletion request and establishes a communication connection from the proxy 13 (2), the proxy 13 (1) has been performing the communication connection with the proxy 13 (3). All communication is switched to the communication connection with the proxy 13 (2).

Next, a case where the proxies 13 (4) and 13 (5) on the session are replaced as in the case of FIG. 8 will be described with reference to FIG. In this example, in FIG. 8, the client application 12 (2), proxy 13 (2), proxy 13 (4), proxy 13
(1) A communication connection is established in the order of the server application 11 (1), and the client application 12 (2) starts from a state in which a session is established between the client application 12 (2) and the server application 11 (1). , Proxy 13 (2),
A communication connection is established in the order of the proxy 13 (5), the proxy 13 (1), and the server application 11 (1), and the path of the session between the client application 12 (2) and the server application 11 (1) is changed. Is assumed.

That is, the proxy 13 on the session
This represents an operation for replacing (4) with the proxy 13 (5). When the mobile terminal 30 (2) receives the proxy replacement request from the agent software, the mobile terminal 30 (2) notifies the session management unit SM (2) of the request.

In this case, the session management unit SM (2)
Is a proxy 13 that has a communication connection
A switching request including the name of the proxy 13 (5) and the connection point as parameters is transmitted to (1) and 13 (2) (S74, S75). The proxies 13 (1) and 13 (2) that have received the switching request establish a communication connection corresponding to the session identifier to the connection point of the proxy 13 (5) based on the received parameters.

Thereafter, the proxy 13 (1)
The communication that has been performed through the communication connection with the proxy 3 (4) is all switched to the communication connection with the proxy 13 (5). Similarly, the proxy 13 (2)
All the communication that has been performed through the communication connection with (4) is switched to the communication connection with the proxy 13 (5).

Proxy 13 added to session
(5) after two communication connections are established,
The two communication connections are associated with each other based on the session identifier received at the time of establishing the connection, and a state in which accumulation and transfer are possible.

[0141]

As described above, according to the communication connection establishing method of the present invention, even during communication, the terminal on which the application used by the user is executed is switched or the communication path used is switched. be able to.
Moreover, even when such switching is performed, there is no need for the user to restart the application or perform a special operation for establishing a communication connection, and the user can continuously receive the communication service.

When switching communication paths and the like, the communication connection between a plurality of proxies is switched according to a predetermined procedure so that the continuity of service is not impaired. Therefore, continuity of service for the same user is guaranteed. You. In addition, since switching, addition, deletion, and replacement of proxies in a communication path can be performed, when the same terminal is used at various positions while moving, the communication path is switched so that a redundant path is avoided. Since a proxy that performs unnecessary relay processing can be deleted from the communication path, communication efficiency can be improved, network resources can be reduced, service continuity can be maintained when the terminal on which the proxy is operating leaves the network, and when a failure occurs. This improves the fault-tolerance of the system.

Further, since the application used during the communication can be switched, the user can selectively use the most suitable application at each time point in the mobile environment, and the convenience is improved. Even when switching applications, continuity of communication services is guaranteed.

[Brief description of the drawings]

FIG. 1 is a sequence diagram showing a control sequence when switching between a proxy and an application.

FIG. 2 is a block diagram illustrating an example of a communication path when switching between a proxy and an application.

FIG. 3 is a sequence diagram showing a control sequence when a proxy is added to a session.

FIG. 4 is a block diagram illustrating an example of a communication path when a proxy is added to a session.

FIG. 5 is a sequence diagram showing a control sequence when a proxy is deleted from a session.

FIG. 6 is a block diagram illustrating an example of a communication path when a proxy is deleted from a session.

FIG. 7 is a sequence diagram showing a control sequence when a proxy on a session is replaced.

FIG. 8 is a block diagram illustrating an example of a communication path when a proxy on a session is replaced.

FIG. 9 is a block diagram illustrating a configuration example of a communication system.

FIG. 10 is a block diagram illustrating a configuration example of a mobile terminal.

FIG. 11 is a schematic diagram illustrating an example of information held by a service management unit SR.

FIG. 12 is a schematic diagram illustrating an example of information held by a position management unit LR.

FIG. 13 is a schematic diagram illustrating an example of information held by a session management unit SM.

FIG. 14 is a block diagram illustrating a configuration example of a communication system.

FIG. 15 is a block diagram illustrating a configuration example of a network.

FIG. 16 is a block diagram showing a movement model of nodes and services.

FIG. 17 is a sequence diagram showing a procedure for updating position information when a terminal moves.

FIG. 18 is a graph showing the number of issued position information update instructions.

FIG. 19 is a graph showing a position search success rate.

FIG. 20 is a graph showing a position search success rate.

FIG. 21 is a block diagram illustrating a configuration example of a network.

FIG. 22 is a sequence diagram showing a service movement example (1).

FIG. 23 is a sequence diagram showing an example of service movement (2).

FIG. 24 is a sequence diagram showing a simplified control sequence when a proxy is added to a session.

FIG. 25 is a sequence diagram showing a simplified control sequence when a proxy is deleted from a session.

FIG. 26 is a sequence diagram showing a simplified control sequence when a proxy on a session is replaced.

[Explanation of symbols]

 1, 3 application 2 proxy 4 node 5 browser 6 proxy 7 Web server 8 node 9 database 10 software 11 server application 12 client application 13 proxy 14 agent 15 link switching unit 16, 17, 18 link 21 Ethernet communication adapter 22 wireless LAN adapter 23 PHS communication adapter 30 Mobile terminal 40 Network 51, 52, 53 Subnetwork 54 Wide area network 55, 59, 60, 61, 66, 67 Mobile terminal 56, 62 Fixed terminal 57, 58, 64, 65 Base station 63 TAP 101, 102 Application 103 Session 104, 105, 106 Proxy 107, 108, 109, 110 Communication connection LR Location management unit S Session management unit SR service management unit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Minoru Kubota 2-3-1 Otemachi, Chiyoda-ku, Tokyo F-term in Nippon Telegraph and Telephone Corporation (reference) 5K030 GA11 HA08 HC01 HC09 JL01 JL07 JT03 KA01 KA05 KA13 LE03 5K033 AA09 CB01 DA01 DA19 DB20 EA07 5K034 AA05 AA17 DD03 EE03 EE09 FF01 HH01 HH02 LL01 MM05

Claims (10)

[Claims] 1. A communication connection establishment method used for controlling a communication system provided with a plurality of applications, a plurality of proxies for relaying communication, and a network connecting the plurality of applications, wherein the plurality of applications are two or more. When communicating with each other via a communication path passing through the proxy, the first proxy arranged on the communication path, in response to the predetermined switching request, A communication connection establishment method characterized by switching to a proxy and continuing communication. 2. A method for establishing a communication connection used for controlling a communication system provided with a plurality of applications, a plurality of proxies for relaying communication, and a network connecting the plurality of proxies, the first application and the second application. A second application that is located on the communication path and relays between the first application and the first proxy when the applications are communicating with each other via a communication path that passes through two or more proxies. A communication connection establishment method, wherein a proxy switches a first application of a communication partner to another third application and continues communication in response to a predetermined switching request. 3. The communication connection establishment method according to claim 1, wherein when the client application and the server application communicate via a plurality of proxies, a response from the server application to the connection request of the client application is transmitted to the client application. When transferred, the transfer path is managed as a session, and a session ID is assigned to each session. When the first proxy receives a switching request for moving a service, the first proxy relays the communication. After the interruption, connect to the third proxy of the movement destination, and then resume the relay. The third proxy starts a new client application using an argument including the corresponding session ID, and is started. New client Application, the third session ID specified by connecting to the proxy
Is transmitted to the third proxy, and the third proxy relays data by linking the communication of the first proxy and the communication of the new client application based on a session ID. A method for establishing a communication connection, comprising: 4. A communication connection establishing method according to claim 2, wherein when the client application and the server application communicate via a plurality of proxies, a response from the server application to the connection request of the client application is transmitted to the client application. When transferred, the transfer path is managed as a session, and a session ID is assigned to each session. When the second proxy receives a switching request for service transfer, it relays communication. Suspending and launching a new client application using the argument including the corresponding session ID, and launching the new client application by connecting to the second proxy and specifying the session ID
To the second proxy, wherein the second proxy links the communication of the proxy having a communication path with the server application and the communication of the new client application based on the session ID. A communication connection establishment method characterized by restarting data relay by using a communication connection. 5. A method for controlling a communication system in which a terminal including a client application for requesting a service, a terminal including a server application for providing a service, and a terminal including a proxy for storing and relaying communication contents are connected. A communication connection establishment method, wherein first information indicating a client application or a server application and a proxy existing in each terminal, and second information used for specifying each terminal are stored, and 1 A communication path between a server application and a client application formed by relaying one or more proxies is managed as a session, and for each session, at least a session identifier, a client application and a server application using the session. Third information identifying the location,
The fourth that identifies the proxy used by the session
Information and the fifth information indicating the connection point of the proxy used by the session, for switching the terminal that provides the server application or the client application to be used, or for communication between the server application and the client application. When it is necessary to switch the proxy on the communication path being used, the server application and the proxy connected thereto are used by using the information of the corresponding session and the first information and the second information. A communication connection establishing method for automatically switching at least one communication connection between a client application and a proxy connected thereto and between a plurality of proxies relaying between a server application and a client application. 6. The communication terminal according to claim 5, wherein at least one mobile terminal provided with a proxy and a server application or a client application on the same terminal is used as a terminal of the communication system. A change in the second information associated with switching of a communication device used for actual communication is absorbed by a proxy arranged on the same mobile terminal. 7. The communication connection establishing method according to claim 5, further comprising a session management unit for managing the information of the session, wherein a first proxy, which is a proxy actually relaying a certain session, is different from another proxy. When a switching request to the second proxy is generated, any one terminal notifies the switching request to the session management unit, and the session management unit switches to the switching destination second proxy. When a notification indicating that the switching preparation has been completed arrives from the second proxy to the session management unit, a communication connection with the first proxy is established. The session management unit switches the second proxy
The third proxy establishes a new communication connection with the second proxy at the switching destination using the session identifier, and transmits the first proxy and the third proxy. The communication performed via the communication connection between the proxy and the third proxy
Is switched so as to pass through the communication connection with the proxy, and when the switching of all communication connections is completed, the completion of the switching is notified to the session management unit. A second communication established between the second proxy and the server application or the client application based on the notified session identifier when the establishment of the first communication connection with the second proxy is completed. A communication connection establishing method, wherein a connection is associated with the first communication connection to switch a communication path of the session. 8. The communication connection establishing method according to claim 5, further comprising a session management unit that manages the session information, wherein a first proxy and a second proxy that are actually relaying communication for a session are provided. A request to add a proxy for adding a new third proxy is generated between any two terminals, and any one of the terminals notifies the session management unit of the addition request; Inquiry about the additional preparation state to the third proxy to be performed, and when the session management unit receives a notification indicating completion of preparation from the third proxy, the session management unit Sending an add request to each of the second proxies, each of the first proxy and the second proxy responding to the add request Te, the third by using the identifier of the session
A new first communication connection or a second communication connection is established with the first proxy, and the communication relayed by the first proxy and the second proxy is the first communication connection or the second communication connection. When the switching of communication connections used for all communications is completed, the switching completion is notified to the session management unit, and the switching between the first proxy and the third proxy is performed. When both the first communication connection and the second communication connection between the second proxy and the third proxy are established,
A method for establishing a communication connection, wherein a first communication connection and a second communication connection are associated based on the notified session identifier. 9. The communication connection establishment method according to claim 5, further comprising a session management unit that manages the session information, wherein a deletion request for a first proxy that is actually relaying communication is generated for a certain session. In this case, any one of the terminals notifies the session management unit of the deletion request, and the session management unit communicates with the first proxy with the first proxy.
Sending a delete request to each of the second proxy and the third proxy that have established the first communication connection and the second communication connection, and the second proxy and the third proxy transmit a delete request between them. The third communication connection is established, the communication using the first communication connection and the second communication connection is switched to the third communication connection, and when the switching of the communication connection is completed, the second proxy is established. A communication connection establishment method, wherein the third proxy and the third proxy respectively notify the session management unit of the completion of switching. 10. The communication connection establishing method according to claim 5, further comprising a session management unit for managing the information of the session, wherein a first communication is performed between a first proxy and a second proxy for a session. A connection is established, a second communication connection is established between the second proxy and the third proxy, and the first proxy and the second proxy are used by using the first communication connection and the second communication connection. When a request for replacement from the second proxy to a new fourth proxy is issued in a state where communication is performed by relaying the proxy and the third proxy, any one of the terminals transmits the replacement request to the fourth proxy. Notifying the session management unit, the session management unit makes an inquiry about the preparation for replacement to the fourth proxy, and notifies the fourth proxy of the completion of preparation. When the session management unit receives the notification indicating the change, the session management unit transmits a switching request to the first proxy and the third proxy, and each of the first proxy and the third proxy In response to the switching request, a third communication connection and a fourth communication connection are established with the replacement fourth proxy based on the session identifier, and the first proxy and the third proxy respectively Is the first
The communication performed through the third communication connection and the fourth communication connection is performed through the third communication connection and the fourth communication connection.
After the switching of the communication connection used for communication is completed for all the switched communication connections, each of the first proxy and the third proxy communicates with the session management unit. The switching completion is notified, and after the third communication connection and the fourth communication connection are established, the third communication connection is associated with the fourth communication connection based on the notified session identifier. Communication connection establishment method.