JP2000165474A - Device and method for data communication and recording medium storing data communication program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To unnecessitate a complex processing considering a processing to be executed in a session layer by means of a host application by permitting a managing part to disconnect a communication line based on the state of a command and to connect the disconnected communication line. SOLUTION: The managing part disconnects the communication line based on the state of the command to be managed and connects the disconnected communication line. A connection operating part 102 is connected to a communication network control part 20, controlled by the host application 30 and a command state managing part 106, also connected to the command state managing part 106 and controlled by the part 106. The connection operating part 102 receives the indication of connecting or disconnecting the communication line from the host application 30 or the command state managing part 106. Moreover, the connection operating part 102 receives the indication for temporarily disconnecting the communication line from the command state managing part 106. The connection operating part 102 receives the indication for re- connecting the temporarily disconnected line from the command state managing part 106.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication control for controlling the temporary disconnection and reconnection of a communication path while maintaining the logical connection of the communication path in a management unit of a session layer and a command layer of an OSI reference model. The present invention relates to an apparatus and a method, and a recording medium on which a data communication program is recorded.

[0002]

2. Description of the Related Art In recent years, there have been many opportunities to perform data communication by connecting an information communication terminal and an information communication terminal or an information communication terminal and a host computer using a communication line.

In data communication using a communication line, a user may be charged according to the time during which the information communication terminal is connected to the partner terminal. For example, when connecting to an information communication network such as the Internet, the user may be charged from a provider that provides a connection service according to the connection time. The user is charged according to the connection time from the provider of the search service when searching data such as a database, or from the mail server administrator when trying to receive the e-mail transmission / reception service. Can be done.

[0004] Therefore, in order to prevent the billing from becoming expensive and to make efficient use of the communication line, a technique for temporarily disconnecting and reconnecting the once connected communication path has been researched and developed. . For example, JP-A-7-123174
Discloses a data communication method and apparatus capable of temporarily disconnecting and reconnecting a physical connection while maintaining a logical connection of a communication path. Here, the “physical connection” of the communication path refers to an actual connection of the communication path between the information communication devices. The “logical connection” of a communication channel is such that even if a physical connection is not established for some reason, the physical connection of the communication channel is apparently maintained by a user or an application. Refers to connection.

[0005] A "logical connection" of a typical communication path is that a relatively lower level layer (for example, a session layer) of the above-described OSI reference model establishes a connection of the communication path while actual data communication is not being performed. The connection that can be seen in the connection method of disconnecting and reconnecting the communication path when it becomes necessary to perform data communication corresponds to this.

[0006]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No.
Utilizing the data communication method and apparatus disclosed in 123174, it is possible to temporarily disconnect or reconnect a physical connection while maintaining a logical connection.

[0007] However, in realizing this, the upper-level application must perform complicated processing for temporarily disconnecting or reconnecting the physical connection of the communication path in consideration of the processing performed in the session layer. Further, when a plurality of higher-level applications are operating, it is necessary to exchange information necessary for temporarily disconnecting the physical connection between the higher-level applications.

[0008] Therefore, the data communication method and apparatus described above are unsuitable for a device such as a portable information terminal, which has a limited processing capability for operating a higher-level application, having a large load.

[0009] Furthermore, the programmer has a lot of processing to be considered when producing a higher-level application, which imposes a heavy burden on the programmer.

[0010]

According to the present invention, there is provided a data communication apparatus for performing data communication, comprising: a connection unit connected to a communication path for performing the data communication; and a state of a command used for the data communication. And a management unit for managing
The connection unit is a data communication control device that disconnects the connected communication path based on the status of the command and connects the disconnected communication path, thereby achieving the above object.

[0011] The information processing apparatus may further include a storage unit for storing information for connecting the disconnected communication path, and connect the disconnected communication path using the information stored in the storage unit.

The command may be a request reply type command.

[0013] The command may be a no-reply type command.

[0014] The command may be a control command for controlling data communication.

The data communication control device further includes a measuring unit for measuring time, and when the management unit determines that the command does not exist, outputs a command to start measuring time to the measuring unit. The measurement unit starts measurement in response to the command from the management unit, and when measuring that a predetermined time has elapsed, outputs a signal indicating that the predetermined time has elapsed to the management unit, The management unit,
The connection unit may disconnect the communication path in response to the signal, and may connect the disconnected communication path to the connection unit in accordance with a change in the state of the command.

The data communication terminal connected to the data communication device via the communication path holds the state of the command in the data communication terminal, and after the disconnected communication path is connected, the state of the command changes. When the management unit determines that the state of the command does not match the state of the command in the data communication terminal, the state of the command may be restored to match.

The data communication terminal connected to the data communication device via the communication path holds the state of the command in the data communication terminal, and after the disconnected communication path is connected, the state of the command is changed. If the management unit determines that the state of the command does not match the state of the command in the data communication terminal, the state of the command may be discarded.

The data communication terminal connected to the data communication device via the communication path holds the status of the command in the data communication terminal. After reconnecting the disconnected communication path, the status of the command is returned. If the management unit determines that the command does not match the status of the command in the data communication terminal, the reconnected connection related to the mismatched command may be discarded.

The data communication terminal connected to the data communication device via the communication path holds the state of the command in the data communication terminal, and after the disconnected communication path is connected, the state of the command is changed. When the management unit determines that the command does not match the status of the command in the data communication terminal, the reconnected connection that handles the mismatched command may be discarded, and a connection related to the command may be automatically established.

A data communication method for performing data communication according to the present invention includes a step of connecting to a communication path for performing the data communication, a step of managing a status of a command used for the data communication, And a step of disconnecting the connected communication path based on the state of the above, and connecting the disconnected communication path, thereby achieving the above object.

[0021] A recording medium storing a data communication program for performing data communication by a computer, wherein the data communication program causes the computer to connect to a communication path for performing the data communication, Lets you manage the state of the commands used,
A recording medium storing a data communication program for disconnecting the connected communication path based on a status of the command and connecting the disconnected communication path, thereby achieving the above object.

[0022]

FIG. 1 is a block diagram of an environment in which a data communication apparatus 100 according to the present invention operates, and FIG.
Is shown.

The data communication device 100 manages the state of the command to temporarily disconnect the connection with the communication device (not shown) of the other party connected via the communication network. It has a function to reconnect with the communication device of the other party. Here, the “command” managed by the data communication device 100 refers to a command or instruction created by an upper application layer or a session layer when performing data communication, such as a transmission / reception request, a response request, and a data processing request. . The command may include a control instruction for controlling data communication, a data communication device, or a data communication terminal.

Hereinafter, the data structure of the command and the type of the command will be described first, and then the general configuration and operation of the data communication apparatus 100 of the present invention will be described.

FIG. 2A shows the data structure of the command 200.

The command 200 has a command ID 200a
, A connection ID 200b, a command status 200c, and a command parameter 200d.

The command ID 200a is information for identifying the type of command. In the present invention, there are two types of commands: a request reply type command and a one-way type command. Both commands are described below.

The connection ID 200b is information for identifying through which connection the data communication apparatus 100 (FIG. 1) executing the command is connected to the communication apparatus of the other party. This information is, for example, information uniquely given to each connection when the data communication device 100 (FIG. 1) connects to a plurality of devices.

The command status 200c is information indicating the status of the command. As described later, the command can take various states such as an initial state, a suspended state, and a reply waiting state while a series of processing related to the command is performed. The command status 200c is information provided for identifying those states. While a series of processing related to the command is performed, the command status 200c is rewritten according to the state of the command.

The command parameter 200d is information indicating what processing the command performs. That is, the command parameter 200d is information indicating the specific contents of the command to be executed. For example, when the command is a command requesting a search for a certain character string, the command parameter 200d stores information indicating that the command is a search command, information indicating a character string to be searched, and the like.

Subsequently, 2 having the above data structure
Each type of command (a request / reply type command and a one-way type command) will be described.

In the following, a request-reply type command means that a transmission side (for example, a client) transmits a processing request (request) to a reception side (for example, a server),
Thereafter, it refers to a data communication command of a type in which the transmission side receives a response (reply) to the request from the reception side. The one-way command is a data communication command of a type in which the transmitting side transmits a request and then terminates the processing, and the receiving side receives the request and terminates the processing.

FIG. 2B shows a state transition of the request / reply type command. More specifically, FIG. 2B shows a command state transition on the side transmitting the request reply type command and a state transition on the side receiving the transmitted request reply type command, respectively.

For a request reply type command, the value of the command ID 200a (FIG. 2A) is a value representing the request reply type command, for example, "0".
It is. The request / reply type command corresponds to, for example, a data search command for searching for specified data.

The state transition of the request / reply type command will be described below. As described in the description of the command status 200c (FIG. 2A), each time a command makes a state transition, the command status 200c (FIG. 2A)
Is also rewritten to a value corresponding to the state after the transition.

First, a request / reply type command is created on the client side (202). The creation of this command is performed according to an instruction from a higher-level application described later. When the command is created, the request related to the content of the command is not yet executed.
This is because creating a command is merely a process of establishing a connection with a server, securing hardware resources, and the like. A command corresponding to the command created by the client is created in the server. When a command is created in the client, the command transitions to the initial state 204,
The command status 200c (FIG. 2A) is rewritten to a value indicating the initial state.

The initial state 204 is a state after the connection with the server is secured and before the processing of the request which is the specific processing content of the created command is started. The initial state 204 of the created command is maintained until a request is given from a higher-level application. For a command for which a request is not given to the initial state 204, the upper application transitions the command to the suspended state 206 based on a predetermined condition.
The command status 200c (FIG. 2A) is rewritten.
The host application can also cause the command in the suspended state 206 to transition to the initial state 204. When the host application gives a request to the command in the initial state 204, the execution of the request is started.

The command to which the request is given is in the request preparation state 2 for transmitting the request to the server.
After 08, the state transits to the request transmission state 210 for transmitting the request to the server. The corresponding command of the server enters the request reception state 220 as soon as transmission from the client starts.

When the transmission of the request from the client to the server is completed, the command transits to a reply waiting state 212 until the host application of the server executes the request and responds (222). While the command is in the reply waiting state 212, the host application of the client can cause the command to transition to the suspended state 214, and can also cause the command in the suspended state 214 to transition to the reply waiting state 212. If the command is executing a request (222), the host application of the server can transition the command to the suspended state (224). Further, the host application of the server can change the command in the suspended state (224) to the request execution state (222).

When the execution of the request is completed, the server prepares the transmission of the reply in order to transmit the execution result to the client (226), and then transmits the reply to the client (228). At the client, the command state changes from the reply waiting state 212 to the reply receiving state 216 upon receiving the reply. When the transmission and reception of the reply are completed in the server and the client, the command processing ends and the connection is closed (218, 230).

As described above, how the state of the command is changed when the request of the request reply type command is executed has been described.

FIG. 2C shows a state transition of a one-way command. More specifically, FIG. 2C shows a command state transition on the side that transmitted the one-way type command and a state transition on the side that received the one-way type command, respectively.

For a one-way command, the value of the command ID 200a (FIG. 2A) is a value representing the one-way command, for example, "1". The one-way command is, for example, a message display command for displaying a predetermined message. The one-way command terminates the process without waiting for a response from the transmission destination, and is therefore called a no-reply command.

The state transition of the one-way command is shown in FIG.
Of the state transition of the request / reply type command described with reference to the description above, the details of the state transition up to the request transmission state (210) are omitted. The difference from the request / reply type command is that the content of the command processing equivalent to “request” in the request / reply type command is a “message” that does not require a reply in the one-way command, and When transmission / reception is completed, the sender
The point is that the command processing ends on the receiving side and the connection is closed.

FIG. 3 shows a data communication apparatus according to the present invention,
This is shown schematically using a reference model.

The following describes how the state transition of the request / reply type command described above is realized in association with the data communication device 500 of the present invention by using the layer of the OSI reference model. In the description, it is assumed that data communication device 500 corresponds to a client (FIG. 2B) and data communication device 550 corresponds to a server (FIG. 2B).
Only the state transition of the request / reply type command will be described, but the case of a one-way command can be described in the same manner.

First, in response to an instruction from the upper application layer, a request / reply type command is created (202 in FIG. 2B). Commands are stored in the command layer 50.
4 are created and managed.

FIG. 4 shows an example of the command management list created by the command layer 504. When a command is created, it is registered in the command management list. Each command registered in the command management list has the data structure described above (FIG. 2A). The “state transition” described below is a command status 200c
This is to rewrite the value of FIG. 2A to a value indicating the state after the transition.

The command created in the command layer 504 is in an initial state (204 in FIG. 2B;
To the reference number). The command creation instruction is simultaneously notified to the session layer 506, and establishes a connection with the session layer 556 of the server 550 via the communication network 10. At this time, the session layer 556 of the server 550 is notified of the type of command received from the session layer 506 of the client 500 (a request / reply type command in the present example). Session layer 5 of server 550
56 sends a command corresponding to the command to the server 55
0 in the command layer 554. The command layer 554 of the server 550 manages the created command.

In the initial state of the command (204),
The command layer 504, based on a predetermined condition such as no request for a predetermined period,
When the command layer 504 receives an instruction to suspend the command transmitted from the command layer 02, the command layer 504 transitions the command for which the suspension instruction has been received to a suspended state (206). Upper application layer 5
02 gives a request to the command in the suspended state (206), the upper application layer 502
The command is transited to the initial state (204), and a request is given to the command.

The upper application layer 502 transmits a request which is a specific processing content of a command to the command layer 50.
4, the command layer 504 starts preparing to send the request to the server 550 (208). Thereafter, when a response indicating that transmission is possible is received from the session layer 506 and preparation for request transmission is completed,
The request is sent to server 550 (210), and server 550 receives the request (220). The request is sent to the upper application layer 552 via the command layer 554 and is executed (222).

The server 550 is executing the request (22
In 2), the command of the client 500 enters a reply waiting state (212). The command in the reply waiting state (212) can transition to the suspended state (214) according to an instruction from the upper application layer 502. At this time, the command of the server corresponding to the command can also transition to the suspended state (224) at the same time. Waiting for reply (21
At the time of transition (214) from 2) to the suspended state, the following operation is performed. First, the command layer 504 is connected to the command layer 55 of the server 550 through the session layers 506 and 556.
4 is also sent an interruption instruction. Server 5 that received the interruption instruction
The 50 command layer 554 shifts the command that has been instructed to suspend among the managed commands to the suspended state (2).
24). Command of server 550 is suspended (514)
To the command layer 50 of the client 500
4 confirms that the command layer 50 of the client 500
4 shifts the command to the suspended state (514). The command of the client 500 and the server 550 in the suspended state (214, 224) transitions to the reply waiting state (212) and the request execution state (222), respectively. Is transmitted, and the transition of the command state is realized.

The upper application layer 5 of the server 550
When 52 finishes executing the request, the result is transmitted to the client 500 via the command layer 554 and the session layer 556 (228). The reply is sent to the upper application layer 502 via the session layer 506 and the command layer 504 of the client 500.

Thereafter, the server 550 and the client 5
00 is closed and the session layers 506, 5
56 notifies the upper application layers 502 and 552 that they have been closed.

As described above, using the layers of the OSI reference model,
It has been described how the state transition of the request / reply type command is realized in association with the data communication device 500 of the present invention.

Among the functions of each layer of the OSI reference model described above, the upper application layer 502 and the command layer 504
And the functions of the session layer 506 correspond to the upper application 30 of the data communication apparatus 100 (FIG. 1) of the present invention.
This is realized by the command state management unit 106 and the connection operation unit 102. The functions of the lower layers below the session layer included in the session layer 506 correspond to the communication network control unit shown in FIG.

In the following, referring to FIG.
The operation and configuration of the command state management unit 1 and the command state management unit 1 will now be described.
06 and the operations and functions of the connection operation unit 102 that are the same as those already described will not be described in detail.

Referring again to FIG. 1, data communication device 100 connects to communication network 10 via communication network control unit 20 to perform data communication with one or more data communication terminals (not shown). I do. The communication network control unit 20 can be, for example, a modem or a transmitter having an optical communication terminal.

Further, in order to operate the data communication device 100, the host application 30 is used. The higher-level application 30 selects a necessary service type for each function in order to receive a service provided by the session layer 506 (FIG. 3). Here, services provided by the session layer 506 (FIG. 3) include control means for data transmission, means for indicating a synchronization point of data transfer,
A service that provides a means for returning the transfer process to the previous synchronization point, that is, a service related to information transfer control is included.

Hereinafter, the configuration of the data communication device 100 will be described.

The data communication device 100 includes a connection operation unit 10
2, a reconnection information storage unit 104, a command status management unit 106, and a timeout measurement unit 108.

The connection operation section 102 performs a temporary disconnection and reconnection of the connected communication path in addition to the connection and disconnection of the communication path to the data communication terminal.

The connection operation unit 102 is connected to the communication network control unit 20 and is controlled by the host application 30 and the command state management unit 106. Connection operation unit 102
Is also connected to the command status management unit 106 and is controlled by the command status management unit 106. Connection operation unit 102
Receives an instruction to connect or disconnect a communication path from the host application 30 or the command state management unit 106.
Further, the connection operation unit 102 receives from the command state management unit 106 an instruction to temporarily disconnect the communication path. The details of the temporary disconnection will be described later. Upon receiving an instruction to perform a temporary disconnection from the command status management unit 106, the connection operation unit 102 outputs information on the current connection including the status of the command at that time to the reconnection information storage unit 104. The connection operation unit 102 issues an instruction for reconnecting the temporarily disconnected communication path again to the command state management unit 10.
Receive from 6. The connection operation unit 102 reads information necessary for reconnecting the communication path from the reconnection information storage unit 104 according to the reconnection instruction received from the command state management unit 106. The connection operation unit 102 reconnects the temporarily disconnected communication path based on the read reconnection information. When the reconnection of the communication path is completed, the connection operation unit 102 outputs a reconnection notification to the command state management unit 106. The connection operation unit 102 outputs a notification indicating that the communication path has been connected for the first time and a notification indicating that the communication path has been finally disconnected.
Send to 0.

When the communication path reconnection notification is output, the connection operation unit 102 sends information on the current connection state of the communication path and information on the command state to the command state management unit 106. The information on the current connection status includes not only the connection status of the data communication apparatus 100 but also information indicating whether a command has been generated by the connected partner or whether the command state of the partner has transitioned. Further, the information on the command includes information indicating whether the command is in an initial state, a reply waiting state, or a request execution state.

The reconnection information storage unit 104 stores the connection operation unit 1
From 02, information required for reconnection is received and the information is stored. Reconnection information storage unit 104 (FIG. 1)
Receives a read command from the connection operation unit 102 when the communication path is reconnected, and outputs information necessary for the reconnection to the connection operation unit 104.

The command status management unit 106 monitors and manages the status of the above-mentioned commands. Here, the monitoring and management of the command status means monitoring and managing the value of the command status 200c (FIG. 2A) of the command.
Before connecting, disconnecting, temporarily disconnecting, or reconnecting the communication path, the command state management unit 106 checks the command status 200c (FIG. 2A) of all commands, disconnects the communication path, or connects the communication path. It is determined whether it is in a good state. If it is determined that the communication path can be disconnected or connected, the command status management unit 106 sends an instruction to the connection operation unit 102 to disconnect or connect the communication path. Alternatively, the command status management unit 106 determines the status of the command being managed by the host application 30.
From the connection operation unit 102 or the higher-level application 30, and receives a command creation instruction, a request processed by the created command, and information necessary for transitioning the state of the command. The command state management unit 106 also receives from the connection operation unit a notification indicating that the connected communication path has been temporarily disconnected or the temporarily disconnected communication path has been reconnected.

Further, when there is no longer any command to be managed, the command state management unit 106 issues a command to the time-out measurement unit 108 to measure the time, and notifies the time-out measurement unit 108 that a predetermined time has elapsed. Receive information to indicate. This predetermined time is a reference time for temporarily disconnecting the communication path, and is set according to the user setting or the congestion state of the communication line.
0 is set. The command status management unit 106 performs processing necessary for temporarily disconnecting the communication path based on the information received from the timeout measurement unit 108. Hereinafter, the case where this predetermined time has elapsed is referred to as “timeout”.

The timeout measuring section 108 receives an instruction for measuring time from the command state managing section 106,
Measure time. When the above-mentioned predetermined time has elapsed,
The timeout measuring unit 108 sends a signal indicating that a timeout has occurred to the command state management unit 106.

The above-mentioned “command” is a request
Intended for reply or one-way commands. However, the connection may be temporarily disconnected by managing the state of the control command, and the connection may be re-established. Here, the control command is a command for controlling data communication or controlling terminals between communication terminals.

FIG. 2D illustrates transition states that can be taken by the control command. When managing the state of the control command, the connection can be temporarily disconnected when the control command is in the interrupted state 412 (FIG. 2D), and then reconnected to return the control command to the original initial state 402 (FIG. 2D). I just need. That is, when the data communication device 100 of the present invention manages a control command, the control command is
0 to interrupted state 4 based on the instruction from 0
12 or transition from the suspended state 412 to the initial state.

Subsequently, referring to the flow charts of FIGS. 5 to 7, the data communication device 100 of the present invention (FIG. 1) temporarily disconnects the communication path temporarily connected (temporary disconnection).
Then, the process of reconnecting (reconnecting) will be described.

FIG. 5 shows the data communication apparatus 100 (FIG. 1) from the time when the communication path is physically connected to the time when the communication path is temporarily disconnected.
2 shows the flow of processing performed by the server.

When the communication path is physically connected (S0
1), the command status management unit 106 (FIG. 1) checks whether a command is present (S02). If a command exists, the command status management unit 106 (FIG. 1) checks whether all the existing commands are in a suspended state (S03). This suspended state is the initial state 2 of the request / reply type command.
04 (FIG. 2B) and reply waiting state 212 (FIG.
The interrupted state 206 or 214 may have shifted from any one of B). Whether each command is in the suspended state can be determined based on whether the value of the command status 200c (FIG. 2A) is a value indicating the suspended state. Command status management unit 10
6 (FIG. 1) instructs the connection operation unit 102 (FIG. 1) to perform a temporary disconnection process when all commands are in a suspended state (S07), and all commands are not in a suspended state. In this case, command monitoring is continued (S
02).

The above-described temporary disconnection processing from (S03) to (S07) is called an intermittent connection method, in which a command reply waiting state generated by application processing is changed to a suspended state to temporarily disconnect a communication path. ,
Refers to a connection method for reconnecting. In other words, the intermittent connection method refers to a connection method in which the communication path is temporarily disconnected (and the communication path is reconnected) in association with the processing of the application.

If no command exists, the command status management unit 106 (FIG. 1)
8 (FIG. 1) is instructed to measure time (S04). Thereafter, when a command is newly created, the command status management unit 106 (FIG. 1) instructs the timeout measurement unit 108 (FIG. 1) to stop measuring time. Then, the command status management unit 106 (FIG. 1) shifts to command monitoring again,
It is checked whether all the commands are in a suspended state (S
03). When a timeout is notified from the timeout measurement unit 108 (FIG. 1) in a state where a command is not newly created (S06), the command status management unit 106 (FIG. 1) temporarily disconnects the connection operation unit 102 (FIG. 1). (S07).

The above-described temporary disconnection process from (S06) to (S07) is called a discrete connection method, in which the communication path is temporarily disconnected (and the communication path is reconnected) without being related to the application processing. Refers to the connection method.

FIG. 6 shows the flow of processing performed by the data communication apparatus 100 (FIG. 1) from the time when the physical connection of the communication path is temporarily disconnected to the time when the communication path reconnection processing is performed.

When the physical connection of the communication path is temporarily disconnected (S08), the command status management unit 106 (FIG. 1)
The status of the command is monitored to determine whether a new command has been created (S09). This is because the creation of a new command means that a communication path needs to be established. The determination as to whether a new command has been created is made based on a change in the contents of the command management list (FIG. 4). The command status management unit 106 (FIG. 1)
When it is determined that a new command has been created, the connection operation unit 1
02 (FIG. 1) to instruct reconnection processing (S13). If it is determined that no new command has been created, the command status management unit 106 (FIG. 1) subsequently determines whether or not all commands are in a suspended state (S1).
0). When the state of all the commands is no longer in the interrupted state, for example, when a request is given to a certain command, the command state management unit 106 (FIG. 1) performs reconnection processing on the connection operation unit 102 (FIG. 1). It is instructed to do so (S13). In the reconnection process, the connection operation unit 102 (FIG. 1) reads the reconnection information stored in the reconnection information storage unit 104 when the command transits to the interrupted state, and performs the connection operation based on the read reconnection information. The unit 102 (FIG. 1) reconnects the communication path. Upon receiving the reconnection notification from the command connection operation unit 102 (FIG. 1), the command status management unit 106 (FIG. 1) normally ends command monitoring for shifting to reconnection (S12).

FIG. 7 shows that the connection operation unit 102 (FIG. 1) of the data communication apparatus 100 (FIG. 1) temporarily disconnects the communication path and performs a reconnection process, and then corrects the command state to the state before disconnection. 2 shows the flow of processing performed by the data communication device 100 (FIG. 1) for this. It is assumed that the data communication terminal of the communication destination in the following description has the same configuration as the data communication device 100 (FIG. 1).

When the reconnection process is executed (S14), the connection of the communication path is completed. The command status management unit 106 (FIG. 1) checks the status of the command in the data communication device 100 and the data communication terminal of the communication destination (S15). here,
“Checking the status of a command” means that the data communication device 10
It refers to checking the correspondence of commands between 0 and the data communication terminal of the communication destination, the number of commands, the command management list (FIG. 4), and the like. When the command states of the command state management units 106 (FIG. 1) of both the data communication device 100 and the data communication terminal match, the correction processing for the command ends normally (S23). If the two command states do not match, the command state management unit 106 (FIG. 1) identifies the mismatched command. The specification of the mismatched command can be performed using the connection ID 200b (FIG. 2A) of both commands. Command status management unit 106 (FIG. 1)
If it is determined that the identified mismatched command can be restored to a normal state (S16), the mismatched command is restored (S22), and the correction process for the command ends normally (S23).

When the command status management unit 106 (FIG. 1) determines that the recovery of the mismatched command is impossible (S1)
6) For example, when it is determined that the application that created the mismatched command hangs up and it is impossible to execute a request related to the command, the command status management unit 106 (FIG. 1) discards the mismatched command. Before proceeding to the processing, it is determined whether or not an abnormal connection is caused by discarding the mismatch command (S1).
7). That is, it is determined whether the reconnected communication path can be maintained. As a result, when it is determined that no abnormality occurs in the connection, the command state management unit 106 (FIG. 1) discards only the mismatched command (S20) and abnormally ends the command correction processing (S21). Based on the abnormal termination of the correction processing, the user can determine that the command state cannot be restored, and issue an instruction to execute the same command as the discarded command via the higher-level application 30 (FIG. 1). It can be carried out. If the command status management unit 106 (FIG. 1) determines that the connection is abnormal, it discards all commands related to the connection (S18) and disconnects the connection (S19).

As described above, the data communication device 100 according to the present invention
Has been described using the flowchart.

The processing procedure according to the above-described flowchart is applied to the processing procedure of the computer program as it is. Therefore, if the computer program including the above procedure is executed by a computer, the effects of the present invention described below can be obtained.

Note that a computer program including such a processing procedure can be stored in a recording medium and distributed. The recording medium includes an optical disk such as a CD or a DVD, a magnetic disk such as an FD, or a semiconductor chip. Further, the recording medium includes a site that stores contents exchanged using a communication medium. For example, when the content is available via a communication network such as the Internet, the site storing the content is included in the concept of the recording medium.

[0085]

According to the present invention, the communication path is disconnected based on the status of the command managed by the management unit and the disconnected communication path is connected, so that the upper application considers the processing performed in the session layer. No complicated processing is required.
Further, when disconnecting the communication path, the plurality of upper applications do not need to exchange information with each other, so that the processing required for disconnecting the communication path is reduced.

Therefore, by using the device of the present invention as a device having a limited processing capability such as a portable information terminal, the communication path can be temporarily disconnected and reconnected without applying a load.

[0087]

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a data communication device according to an embodiment of the present invention.

FIG. 2A is a diagram showing a data structure of a command 200.

FIG. 2B is a block diagram showing a state transition of a request / reply type command.

FIG. 2C is a block diagram showing a state transition of a one-way command.

FIG. 2D is a block diagram showing a state transition of a control command.

FIG. 3 is a diagram schematically showing a data communication device of the present invention using an OSI reference model.

FIG. 4 is a diagram showing an example of a command management list created by a command layer 504 (FIG. 3).

FIG. 5 is a flowchart showing a procedure for shifting to temporary disconnection.

FIG. 6 is a flowchart illustrating a procedure for shifting to reconnection.

FIG. 7 is a flowchart illustrating a procedure for correcting a command after reconnection.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 communication network 20 communication network control unit 30 host application 100 data communication device 102 connection operation unit 104 reconnection information storage unit 106 command state management unit 108 timeout measurement unit

Continued on the front page (72) Inventor Tadazo Tanabe 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka F-term (reference) 5B089 GA04 HB18 JB10 KB00 KC47 KF01 KG06 MC06 MC08 5K033 AA03 BA04 CB01 CB04 DB16 5K034 AA07 CC06 FF01 FF04 FF06 HH01 HH02 HH07 HH11 HH17 HH26 HH65 KK29 LL01 LL02 LL03 LL04 NN26

Claims (12)

[Claims] 1. A data communication device for performing data communication, comprising: a connection unit that connects to a communication path for performing the data communication; and a management unit that manages a state of a command used for the data communication. The data communication control device, comprising: the connection unit disconnecting the connected communication path based on a state of the command, and connecting the disconnected communication path. 2. The communication device according to claim 1, further comprising a storage unit configured to store information for connecting the disconnected communication path, wherein the disconnected communication path is connected using the information stored in the storage unit. Item 2. The data communication control device according to item 1. 3. The data communication control device according to claim 1, wherein the command is a request reply type command. 4. The data communication control device according to claim 1, wherein the command is a no-reply type command. 5. The data communication control device according to claim 1, wherein the command is a control command for controlling data communication. 6. The data communication control device further comprises a measuring unit for measuring time, and when the management unit determines that the command does not exist, the management unit issues a command to start measuring time. The measurement unit starts measurement in response to the command from the management unit, and outputs a signal indicating that the predetermined time has elapsed to the management unit when measuring that a predetermined time has elapsed. The management unit causes the connection unit to disconnect the communication path in response to the signal, and connects the disconnected communication path to the connection unit according to a change in the state of the command. Item 6. A data communication control device according to any one of Items 1 to 5. 7. A data communication terminal connected to a data communication device via the communication path holds a state of a command in the data communication terminal, and after connecting the disconnected communication path, The data communication control device according to claim 1, wherein when the management unit determines that the status does not match the status of the command in the data communication terminal, the data communication control device restores the status of the command to match the status. 8. A data communication terminal connected to a data communication device via the communication path holds a status of a command in the data communication terminal, and after connecting the disconnected communication path, The data communication control device according to claim 1, wherein when the management unit determines that a state does not match a state of a command in the data communication terminal, the state of the command is discarded. 9. A data communication terminal connected to a data communication device via the communication path holds a state of a command in the data communication terminal, and after connecting the disconnected communication path again, The data communication control device according to claim 1, wherein when the management unit determines that the state of the command does not match the state of the command in the data communication terminal, the reconnected connection relating to the mismatched command is discarded. 10. A data communication terminal connected to a data communication device via the communication path holds a status of a command in the data communication terminal, and after connecting the disconnected communication path, 2. The method according to claim 1, wherein when the management unit determines that the state does not match the state of the command in the data communication terminal, the reconnected connection that handles the mismatched command is discarded, and a connection relating to the command is automatically established. ~ 6
2. The data communication control device according to item 1. 11. A data communication method for performing data communication, comprising: connecting to a communication path to perform the data communication; managing a status of a command used for the data communication; A data communication control method comprising: disconnecting the connected communication path based on a state; and connecting the disconnected communication path. 12. A recording medium recording a data communication program for performing data communication by a computer, wherein the data communication program causes the computer to connect to a communication path for performing the data communication. A recording medium recording a data communication program for managing a state of a command used for communication, disconnecting the connected communication path based on the command state, and connecting the disconnected communication path.