JPS6374351A - Data communication equipment - Google Patents

Abstract

PURPOSE:To attain a timer control with high reliability to important data by revising the start timing of a timer supervising the response to the data in response to, e.g. the importance and urgency of the data. CONSTITUTION:A communication control section 1 consists of 5 layers. A control information header 22 is added to the data 21 of a session layer 12 or below. A completed frame added with a header at each layer is sent to a line from the physical layer. In issuing a command or the like at a layer to a low- order layer, at first, the command is generated to the frame, and when it is required to start the timer, the start timing condition of the timer is selected. The selection is executed depending on the importance of the command, in the order of (1) point of time of transmission request from the command issue layer to the low-order layer, (2) point of time sending the frame from the physical layer 16 to the line and (3) point of time when the sent frame transmission is confirmed, and a timer start macro-call is issued to a management module 11 at the point of time based on the selection.

Description

[Detailed Description of the Invention] (Industrial Application Field) Tai Denghuan is a data communication device that performs communication of image file data and character code data, particularly data communication that performs data communication using a communication protocol with a hierarchical structure. It is related to the device.

[Conventional technology]

Conventionally, in this type of device, a timer for monitoring the response waiting time for data issued in a certain layer is started whenever a request is made to transmit that data to a lower layer. Therefore, even if the data sent to the lower layer is important, it is unclear when the data was output to the line or when it reached the other party, and when busy control is performed in the lower layer, The drawback is that a timeout occurs before the data is sent to the line.

[Purpose of the invention]

The present invention aims to eliminate the drawbacks of the prior art described above, and provides a data communication device that can change the activation timing of a timer that monitors a response to certain data depending on the type of data to be sent. It is.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a communication control section of a communication device according to an embodiment of the present invention. In the figure, 1 is a communication control unit composed of five layers, 11 is a management module that interfaces with the terminal side and controls between layers, and 12 has functions necessary to manage data exchange. The session layer 13 has the function of controlling the flow of transparent data between session layer entities, and the transport layer performs data transfer between ends on behalf of the session layer. The transport layer 14 establishes, maintains, and terminates connections between systems. 15 is a network layer that handles the establishment, maintenance, and release of data link connections between entities, and has functions and control procedures for transferring data link frames; 16 is an electrical and mechanical layer; It is the physical layer that specifies physical and procedural characteristics and handles the activation, maintenance, and deactivation of physical connections. FIG. 2 is a diagram showing frames used for exchanging information between each layer. Ladders 22 are added to the data 21 of the session layer 12 to control information in each layer below it. The header 22 contains information defined by the peer protocol. A header is added to each layer and the completed frame is sent to the line from the physical layer. When the other device receives it, each layer removes the header from the frame and the data is passed on to the session layer in its original form.

FIG. 3 is a diagram showing a frame in which a timer control information section is added to the frame in FIG. 2.

FIG. 5 is a flowchart showing the timer activation process of this embodiment. When a certain layer issues a command or the like to a lower layer, the command is first created on a frame in S31. It is then determined at 332 whether the command requires starting a timer. If it is necessary to start the timer, the process goes to 333; otherwise, the process goes to S47. In S33, the timer activation timing condition is selected. This selection depends on the importance of the command: ■ at the time when the command issuing layer makes a transmission request to the lower layer, ■ at the time when the frame is sent to the line from the physical layer 16, and ■ at the time when the delivery of the transmitted frame is confirmed. Either
The higher the degree of importance, the more ■ is chosen over ■, and the more ■ is chosen over ■. S3
In step 4, the timer activation timing is determined based on the selection in S35, and in the case of timing condition (3), the process advances to S35, and a timer activation macro call is issued to the management module at the time when a command is requested to be transmitted to the lower layer. S
In step 36, a command is issued to the lower layer, and in step S37, the frame is sent from the physical layer to the line. Timing conditions ■,
In the case of ■, S38. In S39, conditions (2) and (2) are set in the timer control information section 23 of the frame, and in S40, a command is issued to the lower layer. In S41, the timer control information part is checked in the data link layer. If it is determined in S42 that the timing condition is ■, the frame is sent from the physical layer to the line in 343, and the frame is sent to the management channel in S46. . If it is determined in S42 that the timing condition is ■, then S4
4, the frame is sent to the line. Then, if it is determined that the frame sent in S45 has been delivered to the other party's device, S4
At step 6, a timer activation macro call is issued to the management module.

FIG. 4 is a diagram showing an example of the timer control information section 23. 24 is a command activation condition section indicating whether the timer activation condition is ■ or ■; 25 is a command issuing layer identification section indicating whether the command is issued from the layer; 26 is a timer value section indicating the timer value; and 27 is a timeout. This is the timer-out notification code section that shows the notification code at time.

According to the above embodiment, depending on the importance of the command,
The activation timing of the timer that monitors the response has been changed, but this is not limited to the importance of the command.
For example, it is possible to change it depending on the urgency of the command.

(Effects) As explained above, according to the present invention, the activation timing of the timer that monitors the response to data can be changed depending on the importance and urgency of the data, so important data can be trusted. Accordingly, it is possible to provide a data communication device that can perform highly flexible timer control.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a communication control unit in an actual bN example of the present invention. FIGS. 2, 3, and 4 are configuration diagrams of frames used for exchanging information. FIG. 5 shows a timer activation process. FIG. 1 is a communication control unit, 11 is a management module, 12 is a session layer, 13 is a transport layer, 14 is a network layer, 15 is a data link layer, and 16 is a physical layer.

Claims (2)

[Claims] (1) In a data communication device that performs data communication using a communication protocol with a hierarchical structure, data is issued from a certain layer of the above-mentioned hierarchical structure, and the activation timing of a timer that monitors the response to that data depends on the type of data being sent. A data communication device characterized by changing. (2) In item 1, the timing of starting the timer depends on the type of data; it starts when the data is requested to be transmitted to the lower layer; it starts when the data is sent to the line;
A data communication device characterized in that the device changes to one of the activation modes when delivery is confirmed at the lowest layer.