JPH0440131A - Token priority control managing system for token path transmission - Google Patents

Abstract

PURPOSE:To enable efficient priority control by storing the degree of emergency and the number of times for transmission for each station and deciding or changing the priority level of each station by a management station based on these data such as the degree of emergency and the number of times for transmission. CONSTITUTION:A token management station STM investigates the number of times for transmission and the level of the degree of emergency for respective normal stations ST0-ST2 and based on these data, the priority level is individually decided for the respective normal stations ST0-ST2. Then, the decided priority levels are set to the respective normal stations ST0-ST2, and the tone priority level of the highest level is set to the priority order field of a token frame first of all. Each time a token turns around, the token priority level is turned around while successively changing the level in a low-order direction.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is a local area network (LAN) in which a plurality of information processing devices F (computers, terminals, sequencers, etc.) are connected in a bus type or ring type. The present invention relates to a token priority control management method for token path transmission in which access control is performed by circulating tokens having a rank.

[Conventional technology]

The following three methods have been proposed as conventional token priority control management methods for token path transmission.

■ This method determines the priority level by changing the token capturing frequency of each station.The initial value setting register and its initial value are loaded to set values according to the station's priority, and each time a token is detected at the time of a transmission request. A method that consists of a counter that decrements by "1" and captures and controls an actual token when a token is detected a predetermined number of times (see Japanese Patent Laid-Open No. 107664/1983).

■ A priority level is set depending on the type of transmission data, and the token is also made to recognize the priority level, and the transmission data with the priority level is circulated preferentially.The token recognition circuit classifies the token and recognizes the token type. A priority comparison circuit compares the signal corresponding to the token with the signal corresponding to the type of data transmitted from the transmitting register, and if the priority level of the token is high, the transmission line is set so that the transmission frame of the receiving register is directly sent to the station. A method of switching the switching circuit switch and then switching the transmission line switching circuit to put the transmission line in an open mode (see Japanese Patent Laid-Open No. 161048/1983).

■ By providing a priority processing function to information transmission frames and token frames, urgent transmission requests are prioritized, and when an urgent transmission request is output from the central processing unit (CPU), the station is prioritized. A system in which a priority level holding circuit stores the priority level, compares the priority level with the own station's priority level, and if the latter is greater or equal, captures a token frame and transmits the information (Japanese Patent Laid-Open No. 59 (Refer to Publication No.-250).

[Problem to be solved by the invention]

However, in the above-mentioned conventional token priority control management method for token path transmission, the priority level setting is determined in advance by each station, in an emergency, or by data to be processed preferentially, and the traffic of a certain station is Deciding and changing priority levels flexibly and dynamically for the entire network, such as changing priority levels to correct imbalances in volume and temporarily raising priority levels of frequently accessed stations to improve transmission efficiency. There were unresolved issues that could not be solved.

Therefore, this invention was made by focusing on the unresolved problems of the conventional example, and by installing a station that manages the priority level, it is possible to add to the priority level of data to be processed in an emergency or on a priority basis. The purpose of this paper is to provide a token priority control management method for token path transmission that can perform priority control considering the entire network.

[Means to solve the problem]

In order to achieve the above object, a token priority control management method for token path transmission according to the present invention provides a token path transmission method for transferring transmission rights by circulating tokens having priority among a plurality of stations connected to a transmission path. During transmission, a token management station is connected to the transmission path, and each station connected to the transmission path stores the number of transmissions and the degree of urgency from the control unit, and the token management station stores the stored contents of each stage tongue. investigate,
It is characterized in that the priority level of the token of each station is determined or changed.

[Effect]

In this invention, each station connected to the transmission path stores the number of transmissions and the degree of urgency from the control unit, and by connecting a token management station to the transmission path,
In addition to controlling the priority level of data to be processed in emergencies or on a priority basis, this token management station can perform priority control that takes the entire network into consideration.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In the figure, ST is a token management station that manages the priority level of tokens, and this token management station ST and a plurality of normal stations S Te to S
T t are connected in a ring shape by a transmission path.

As shown in FIG. 2, the transmission frame F includes a start flag F3 for indicating the start of the frame and maintaining synchronization, and an address section A for indicating the addresses of the source and destination.
, a control section C for classifying frame types and various monitoring controls, and an information section I for storing information data of arbitrary length.
, a frame check sequence FC3 that stores, for example, a CRC error control sequence for checking whether each data from the address part A to the information part I has been transmitted correctly, and an indication of the end of the frame. It consists of an end flag F1. Here, the types of frames include a token pass frame that transfers transmission rights,
There are information transmission frames that transmit information to other stations, information request frames that request information from other stations, response frames to this information request frame, control frames that control the operating status of stations, etc. In the case of a transmission frame, data is stored in the information section I, and the token pass frame is composed of a start flag F', an address section A, a control section C, a frame check sequence FC3, and an end flag F.

Each of the normal stations ST, .about.ST, is equipped with a token acquisition control section shown in FIG.

This talk capture control unit requests a priority level setting from a token recognition circuit 1 that recognizes a received token, a priority level detection circuit 2 that detects the priority level of the token recognized by this token recognition circuit, and a management station ST. The station priority level register 3 that is set when or a priority level comparison circuit 4 which outputs a comparison signal of logical value "1" when the level is high, an AND gate 5 to which the comparison signal of this priority level comparison circuit 4 and the transmission request signal are input, and this AND It includes a transmission counter 6 to which the output of the gate 5 is input and counts the number of transmissions, and an urgency display register 7.

Therefore, in the initial state, the value of the station priority level register 3 is the same level for all normal stations ST, ~ST, and equal communication is performed among them, while the token management station ST is at the highest level. level.

The token management station ST executes the process shown in FIG. 4 to investigate the number of transmissions and the urgency level of each normal station ST. The priority level of each normal stage town ST is determined individually, and the determined priority level is
, ~ST, and first set the highest token priority level in the priority field of the token frame, and each time the token circulates, the token priority level is sequentially changed downward.

Next, the operation of the above embodiment will be explained with reference to the flowchart of FIG. 4 showing the priority level control processing of the token management station ST.

First, in step ■, each normal station ST.

~ST, as shown in FIG. 5(a), transmits a transmission frequency counter activation command 20 for activating a transmission frequency counter. When each normal station ST, ~ST, receives the transmission frequency counter activation command 20, it clears the transmission counter 6 and starts counting the number of transmissions.
Next, the process moves to step (2), where it is determined whether or not a predetermined time TI has elapsed. If the predetermined time T has not elapsed, the process waits until the predetermined time elapses, and when the predetermined time T1 has elapsed, the process proceeds to step (2). to move to.

In this step (2), as shown in FIG. 5(b), a transmission request frame is created that includes a transmission frequency investigation request command 30 for investigating the transmission frequency and emergency 21st degree of each normal station ST, ~ST, This is applied to each normal station ST.
,~ST! , and then move on to step ■.

Each of the normal stations ST, ~STz, which received this transmission frequency investigation request command 30,
As shown in FIG. 3, a response frame including a format consisting of a transmission frequency investigation response command 40, an own station stage address 41, a transmission frequency 42, and an urgency level 43 is created and sent back to the management station ST.

In step (2), it is determined whether or not a transmission frequency response has been received from the normal station ST, ~ST3. If the transmission frequency response has not been received, the process waits until the transmission frequency response is received, and when the transmission frequency response is received, the process proceeds to step (2). Then, it is determined whether or not the reception of transmission count responses from all normal stations ST to ~ST has been completed, and if there is a station that has not received a transmission count response, returns to step (2) and steps (2) and (2) for the station that has not received a transmission count response. Repeat the process (2) for all normal stations ST, ~ST.

When the reception of the transmission frequency response is completed, the process moves to step (3).

In this step ■, each normal station ST.

A priority level determination process is performed in which the number of transmissions and the urgency level of ~STt are statistically processed and the priority level is determined by the following method.

(1) Each normal station ST, ~ST depending on the degree of emergency
: Determine the priority level of.

(2) Increase the level of frequently accessed stations to improve transmission efficiency.

(3) In order to correct the variation in the data amount of each normal station ST, ~ST, lower the level of the frequently accessed station.

(4) Change the priority level of a specific station on a test basis.

When the priority level of each normal station STo to ST2 is determined in this way, the process moves to step (2), and as shown in FIG. 5(b), each normal station STo
A transmission frame including a format consisting of a priority level setting command 50, a station address 51, and a station priority level 52 is created for each of the normal stations S T o to S T r, and is transmitted to each of the normal stations S T o to S T r.

Next, proceed to step ■ and set the token priority level N.
is set to the highest level "4", and then moves to step (2) to determine whether or not a predetermined time T2 has elapsed; when the predetermined time T2 has elapsed, return to step (2);
If the predetermined time has not elapsed, the process moves to step [phase], sets the token priority level N in the priority field of the token frame, sends the token frame to the transmission path, and then moves to step (2).

In this step ■, each normal station ST.

It is determined whether or not the token frame that circulated through ~ST has been received. If the token frame has not been received, it waits until it is received. When the token frame is received, it moves to step @ and sets the token priority level N. The value obtained by subtracting "1" from is set as a new token priority level N, and then the process moves to step @.

In this step @, the token priority level N is "1"'
If N>1, the process returns to step [phase], and if N=1, the process returns to step (2) to set the highest token priority level N.

Therefore, by performing the process shown in FIG. 4 at the management station STM, each normal station S T
A station priority level is set in the station priority level register 3 of ~STt.

For this reason, each normal station ST o to ST.

When a token frame is received, the token recognition circuit 1 recognizes the token frame addressed to itself, and the token priority level detection circuit 2 determines the token priority level stored in the priority field included in the token frame. The priority level comparison circuit 4 compares the token priority level with the station priority level stored in its own station priority level register 3, and determines that the latter is equal to or higher than the former. Sometimes, token capture control is performed, and when there is transmission data in the control section and a transmission request signal RQSND is supplied to the AND gate 5, the transmission counter 6 is incremented by "1" and the transmission frame is transmitted. do.

At this time, each normal station S T o - ST.

An example of the relationship between the priority level and the token priority level is shown in FIG.

In addition, in the above embodiment, the case where the number of stations connected to the transmission path is "3" was explained.
The number of token management stations ST is not limited to this, and any number can be selected, and the token management station ST does not need to be an independent station, and a token management function may be added to a normal station.

Further, in the above embodiment, the case where a ring type network is constructed has been described, but the present invention can also be applied to the case where a bus type network is constructed.

〔Effect of the invention〕

As explained above, according to the present invention, a token management station is provided to manage the priority order of tokens connected to a transmission line, and each station stores the degree of urgency and the number of transmissions. Since the management station determines or changes the priority level of each station based on the number of transmissions, efficient priority control can be performed, and the levels of all stations can be unified, equalized, and urgent. 2. It is possible to flexibly set the priority level in accordance with temporal changes based on the parameters such as frequency and number of transmissions.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the structure of a transmission frame, FIG. 3 is a block diagram showing a token capture control circuit of a normal station, and FIG. 4 is a block diagram showing a management station. 5(a) to 5(b) are explanatory diagrams each showing a format for providing a detailed explanation of the present invention, and FIG. 6 is a flowchart showing an example of priority level control processing in FIG. FIG. In the figure, L is a transmission path, ST is a token management station, ST0 to ST2 are normal stations, 1 is a token recognition circuit, 2 is a token priority level detection circuit, 3 is a station priority level register, 4 is a priority level comparison circuit,
6 is a transmission counter, and 7 is an urgency display register.

Claims (1)

[Claims] In token pass transmission in which transmission rights are transferred by circulating tokens with priority among a plurality of stations connected to a transmission path, a token management station is connected to the transmission path, and each station connected to the transmission path , the token management station stores the number of transmissions and the degree of urgency from the control unit, and also examines the memory contents of each station and determines or changes the priority level of the token of each station. Token priority control management method for token path transmission.