JP2003198574A - Communication control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication control system capable of preventing the extension of a communication processing time in a LAN configured to circulate a transmission right, to enable a node acquiring the transmission right to perform a transmission only for a prescribed time and to perform communication between two nodes by data transmission and a response. <P>SOLUTION: Each of nodes connected to the LAN is provided with a transmission data queue 2 for temporarily storing ACK data corresponding to transmitting data formed by a data transmission processing part 1 to be transmitted from the present node to the other node and received data received from the other node by a data receiving part 6, a data transmission part 5 for transmitting the data stored in this transmission data queue 2 to the other node and a transmitting data amount detecting part 3 for detecting the amount of the data stored in the transmission data queue 2 and when the amount of the data in the transmission data queue 2 detected by the transmission data amount detecting part 3 exceeds a decision reference value K, the data are transmitted by extending the prescribed data transmission time. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a communication system in which a transmission right is circulated, and a node that has acquired the transmission right can transmit only for a predetermined time. Data transmission and ACK ( The present invention relates to a LAN communication control method for performing communication by exchanging a pair of data of a positive response) and a command and a response.

[0002]

2. Description of the Related Art FIG. 7 is a diagram showing a configuration of each node used in a conventional communication control system. In FIG. 7, 1 is a data transmission processing unit for transmitting data to another node, 2 is a transmission data queue for temporarily storing transmission data and ACK data for data received from another node, 4
Is an ACK data generation unit that generates ACK data for data received from another node, 5 is a data transmission unit that transmits data in the transmission data queue 2 on the communication path, and 6 is a data reception unit that receives data from another node Then, the received data is passed to the ACK data generator 4. FIG. 8 is a diagram showing a data transmission process between nodes in the conventional communication control method, and schematically shows data transmission / reception between nodes.

Next, the operation will be described. Each node on the communication path is configured as shown in FIG. 7, and the transmission right is circulated between the nodes in order, and only when the transmission right is acquired, the transmission of the predetermined time or the predetermined number of packets is performed. Can be performed from the data transmission unit 5. The communication between nodes is data transmission and ACK (acknowledgement) as shown in FIG.
Is performed by a pair of data exchanges. That is, as the communication processing of each node, the data transmission processing unit 1 activates the data transmission processing, transmits data from the data transmission unit 5 to another node via the transmission data queue 2, and then transmits an ACK from the destination node. When the data receiving unit 6 receives the data and notifies the data transmission processing unit 1, one communication ends. However, the timer is monitored from the data transmission unit 5 to the reception of the ACK, and if the time-out occurs, the retry transmission is performed. In addition, data transmission is done by ACK of the previous transmission data.
May be performed after receiving the ACK or before receiving the ACK of the previously transmitted data. Therefore, since each node can be either a transmitting side or a receiving side, transmission data to another node, retry transmission data, and ACK for transmission data from another node are accumulated in the transmission data queue 2 and transmitted. When the right is obtained, it is sequentially transmitted only within the specified time (or the specified number of packets).

[0004]

In the above method, although the communication is performed by a pair of data exchange of data transmission and ACK, each node equally transmits data, so that, for example, a plurality of nodes are short. When data is intensively transmitted to a specific node in a cycle, a large number of ACKs to be transmitted and own transmission data are accumulated in the transmission data queue 2 in the specific node that receives data intensively.
As a result, it is necessary to acquire the transmission right multiple times before transmitting the ACK, the time until the ACK is returned increases, the communication processing time for one time increases, and the performance of the entire system deteriorates. Further, if the time until the ACK is returned further increases, the ACK wait time-out occurs, retry data transmission is performed, the degree of concentration of data transmission increases, and the communication processing time for one time further increases. Will increase.

The present invention has been made in order to solve the above-mentioned problems, and is a communication system in which a transmission right is circulated so that a node having the transmission right can transmit only for a predetermined time. In a LAN configured to perform data transmission and ACK between two nodes by exchanging a pair of data such as ACK or command and response, even when communication is concentrated from a plurality of nodes to a specific node, the communication processing time is reduced. It is an object of the present invention to obtain a communication control method capable of preventing the increase as much as possible.

[0006]

In the communication control system according to the present invention, the transmission right is circulated between the nodes connected by the LAN, and it becomes possible for the node having the transmission right to transmit the data for a predetermined time. In the communication control method that is configured and performs one-time communication by data transmission and a response to this data transmission, each node has a data receiving unit that receives data from another node, and a node from its own node to another node. A transmission data queue for temporarily storing the transmission data to be transmitted and the response data to the reception data from the other node received by the data receiving unit, and the data for transmitting the data stored in this transmission data queue to the other node. It is equipped with a transmission unit and a response data amount detection unit that detects the amount of response data in the transmission data queue. If the response data of detected transmission data queue has exceeded a predetermined value is obtained so as to extend the predetermined time of the data transmission by the data transmission unit.

Further, the predetermined time for data transmission by the data transmission unit is divided into transmission data from the own node and response data, and when the response data amount exceeds a predetermined value, the response data is extended. It is something. Further, the predetermined time for data transmission by the data transmitting unit is such that the amount of response data is extended and the amount of transmission data from the own node is shortened.

The data transmission by the data transmission unit is performed in packets, and the predetermined time for data transmission by the data transmission unit is extended by increasing the number of packets to be transmitted.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. Embodiment 1 of the present invention will be described below with reference to the drawings. 1 is a diagram showing a configuration of a communication control system according to a first embodiment of the present invention. In FIG. 1, 1 is a data transmission processing unit for transmitting data to another node, 2 is a transmission data queue for temporarily storing transmission data and ACK data for data received from another node, 3 is a transmission data queue 2 A transmission data amount detection unit for detecting the amount of data stored in the storage device, 4 is an ACK data generation unit for generating ACK data for data received from another node, and 5 is transmission data of the transmission data queue 2 to another node on the communication path. Data transmission unit, 6
Is a data receiving unit that receives data from other nodes,
The received data is passed to the ACK data generation unit 4, and when the ACK is received, the data transmission processing 1 is notified.

FIG. 2 is a flow chart showing the processing of the communication control method according to the first embodiment of the present invention. Figure 3
FIG. 6 is a diagram showing a data transmission timing of the communication control method according to the first embodiment of the present invention. In FIG. 3, 7 is a temporarily extended transmission time.

Next, the operation will be described. Each node on the communication path constituted by the bus type or loop type LAN is configured as shown in FIG. 1, and the transmission right is circulated between the nodes in order, and only when the transmission right is obtained, a predetermined predetermined The data transmitting unit 5 can transmit the time or a predetermined number of packets. The basic operation of the configuration of FIG. 1 is similar to the operation of FIG. In FIG. 1, in addition to this, a transmission data amount detection unit 3 for detecting the amount of data accumulated in the transmission data queue 2 is provided, and a data amount equal to or larger than the value in the transmission data queue 2 is accumulated at the time of data transmission. In this case, the data transmission time when the transmission right is acquired is extended. The following is a description according to the flowchart in FIG. When the node acquires the transmission right in step S1, the timer for determining the transmission time is cleared and counting is started in step S2. Next, in step S3, the amount of data accumulated in the transmission data queue 2 is detected by the transmission data amount detector 3, and if the amount of data is less than a preset reference value K, step S3.
In step 4, the normal maximum transmission time T1 is set, and when the data amount is equal to or larger than the preset determination reference value K, in step S5, the extended maximum transmission time T2 is set as the maximum transmission time.

After that, in step S6, when the transmission data exists and the maximum transmission time has not been reached, in step S7, the transmission timer is updated (step S8), the data is transmitted sequentially, and the transmission data is transmitted. If it disappears or the maximum transmission time is reached, step S
At 9, the transmission right is passed to the next node and the transmission process is stopped. As a result of the above processing, as shown in FIG. 3, when each node normally obtains the transmission right, the data transmission is performed in the same time width. As described above, the transmission time is temporarily extended.

According to the first embodiment, as a result, the transmission data accumulated in the transmission data queue 2 can be efficiently transmitted, and the communication processing can be performed even when the communication is concentrated from a plurality of nodes to a specific node. It is possible to prevent an increase in time as much as possible.

Embodiment 2. FIG. 4 is a diagram showing the configuration of the communication control system according to the second embodiment of the present invention. Figure 4
1, 2, 4, and 6 are the same as those in FIG. Reference numeral 8 denotes an ACK data amount detection unit (response data amount detection unit) that detects the ACK data amount in the transmission data queue 2. In the first embodiment, the transmission data amount detection unit 3
Although the data amount of all the data in the transmission data queue 2 is detected in the second embodiment, as shown in FIG.
Since only the ACK data is detected by the CK data amount detection unit 8, only when the communication is concentrated from a plurality of nodes to the specific node (= the ACK data increases), the communication processing time is increased as much as possible. It becomes possible to prevent it.

According to the second embodiment, since only the amount of ACK data is detected, it is possible to detect only when communication is concentrated from a plurality of nodes to a specific node, and it is possible to prevent an increase in communication processing time.

Embodiment 3. FIG. 5 is a diagram showing a transmission time of the communication control method according to the third embodiment of the present invention.
In FIG. 5, 9 is the maximum transmission time in which the transmission time for ACK data is extended. In the second embodiment, the data transmission time when the transmission right is acquired is the transmission data from the own node,
Although both ACK data transmissions are managed together, in the third embodiment, as shown in FIG. 5, there are two types of transmission data maximum transmission time Td from its own node and ACK transmission data maximum transmission time Ta. The maximum data transmission time Ta for ACK transmission is extended to increase the maximum transmission time for ACK data, such as the maximum transmission time 9 in which the transmission time for ACK data is extended only when there is a lot of ACK data. The transmission time is Tal.

According to the third embodiment, the same effect as that of the second embodiment can be obtained.

Embodiment 4. FIG. 6 is a diagram showing the transmission time of the communication control method according to the fourth embodiment of the present invention.
In FIG. 6, 10 is the maximum transmission time in which the transmission time for the transmission data is shortened by the extension of the transmission time for the ACK data. In the third embodiment, the data transmission time when the transmission right is acquired is the maximum transmission time T for transmission data from the own node.
d, the case in which the data maximum transmission time Ta for ACK transmission can be set in two types and the data transmission time for ACK transmission is extended only when there is a large amount of ACK data has been described. It is possible to set two types of maximum transmission times as in the case of the form 3, and as shown in FIG.
By extending the K data maximum transmission time Tal, the maximum transmission time Tdl for transmission data from the own node is shortened to
The maximum transmission time 10 is formed by shortening the transmission time for the transmission data by the extension of the transmission time for the CK data.

According to the fourth embodiment, the same effect as that of the third embodiment can be obtained, and the maximum value of the transmission time per node can be kept constant.

[0020]

Since the present invention is constructed as described above, it has the following effects. Also,
The transmission right is circulated between the nodes connected by the LAN, and the node that has acquired the transmission right is configured to be able to transmit data for a predetermined time, and one communication is performed by the data transmission and the response to this data transmission. In the communication control method to be performed, each node has a data reception unit that receives data from another node, transmission data that is transmitted from the own node to another node, and reception data from another node that is received by the data reception unit. Transmission data queue that temporarily stores the response data for the, the data transmission unit that transmits the data stored in this transmission data queue to another node, and the response data amount detection that detects the response data amount in the transmission data queue If the response data amount of the transmission data queue detected by the response data amount detection unit exceeds a predetermined value, the Since the predetermined time for data transmission by the data transmission unit is extended, by detecting the response data amount, it is possible to detect only when communication is concentrated from a plurality of nodes to a specific node and prevent an increase in communication processing time. be able to.

Further, the predetermined time for data transmission by the data transmission unit is divided into transmission data from the own node and response data, and when the response data amount exceeds a predetermined value, the response data portion is extended. Therefore, even when communication is concentrated from a plurality of nodes to a specific node, the response data can be extended and the communication processing time can be prevented from increasing. Further, the predetermined time for data transmission by the data transmission unit is shortened by the amount of response data extended and the amount of transmission data from the own node, so the predetermined time for data transmission of each node can be kept constant. Becomes

Further, the data transmission by the data transmission unit is carried out in packets, and the extension of the predetermined time for data transmission of the data transmission unit is carried out by increasing the number of packets to be transmitted. Can be extended by the number of packets.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a communication control system according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing processing of the communication control method according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a data transmission timing of the communication control system according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a communication control system according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a transmission time of the communication control method according to the third embodiment of the present invention.

FIG. 6 is a diagram showing a transmission time of the communication control method according to the fourth embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of each node used in a conventional communication control method.

FIG. 8 is a diagram showing a data transmission process between nodes of a conventional communication control system.

[Explanation of symbols]

1 data transmission processing unit, 2 transmission data queue, 3 transmission data amount detection unit, 4 ACK data generation unit, 5 data transmission unit, 6 data reception unit, 7 extended transmission time, 8 ACK data data amount detection unit, 9 Maximum transmission time with extended transmission time for ACK data, 10 AC
The maximum transmission time for which the transmission time for transmission data has been shortened by the amount of extension of the transmission time for K data.

Claims (4)

[Claims] 1. A transmission right is circulated between nodes connected by a LAN so that data can be transmitted from a node that has acquired the transmission right for a predetermined time, and data transmission and a response to this data transmission are performed. In the communication control method in which the communication is performed once by each node, each node receives the data from the other node, the data receiving unit, the transmission data transmitted from the own node to the other node, and the data receiving unit. A transmission data queue that temporarily stores response data to the reception data from another node, a data transmission unit that transmits the data stored in this transmission data queue to another node, and response data in the transmission data queue A response data amount detection unit for detecting the amount, and the response data amount of the transmission data queue detected by the response data amount detection unit. A communication control method, wherein when the data amount exceeds a predetermined value, a predetermined time for data transmission by the data transmission unit is extended. 2. The predetermined time for data transmission by the data transmission unit is divided into transmission data from the own node and response data, and when the response data amount exceeds a predetermined value, the response data is extended. The communication control method according to claim 1, wherein the communication control method is performed. 3. The communication control system according to claim 2, wherein the predetermined time for data transmission by the data transmission unit is shortened by the amount of response data extended and by the amount of transmission data from the own node. 4. The data transmitting unit transmits data by packets, and the predetermined time period for data transmitting by the data transmitting unit is extended by increasing the number of packets to be transmitted. The communication control device according to any one of claims 1 to 3.