JPS61285846A - Priority communication control system - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency by changing communication priority designation information at the reception of a token in a specific transmitter and changing the opportunity of communication right acquisition depending on the communication quantity of the transmitter. CONSTITUTION:In the priority communication control system of a network system where plural transmitters are connected via a communication medium and only a transmitter acquiring the communication right by using a token being a communication right transfer instruction obtains the transmission right, a token including communication priority designation information is received, the information is sent by a transmission request as the communication right acquisition only when the communication priority designation information of the own equipment is higher depending on the said communication priority designation information and in other case, the communication right is not acquired even with the reception of a token and the token is circulated to the next nodes. Then the communication priority designation information is changed to a specific transmitter in the network system to attain much communication right transfer to a device with higher sending frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application] The present invention relates to a priority communication control system, and particularly to a priority communication control system that controls transfer of communication rights using communication priority designation information in a token.

[Summary of Disclosure] This specification and drawings describe a priority network system in which a plurality of transmission devices are connected via a communication medium, and only the transmission device that has acquired the communication right using a token, which is a communication right transfer command, can obtain the transmission right. In the communication control method, the token includes communication priority designation information, and the holding means holds the communication priority of the own device in the transmission device; a comparison means for comparing the information with the communication priority designation information; a communication right acquisition determining means for determining whether or not to acquire the communication right based on the comparison result of the comparison means; Furthermore, the specific transmission device is provided with a changing means for changing the communication priority designation information in the token, and the specific transmission device changes the communication priority designation information when receiving the token, and increases the chances of acquiring communication rights depending on the communication volume of the transmission device. The present invention discloses a technology that enables efficient allocation of communication rights according to the amount of communication and improves transmission efficiency.

"Prior Art" A so-called local area network "LAN" is a so-called local area network in which a large number of transmission devices (hereinafter referred to as notebooks) are connected together using a single transmission path, and data communication is performed between these nodes.
is popular. Among the various communication methods in LAN,
The token passing method is particularly advantageous in that it can equally provide communication services to all nodes even when the network is in a high traffic state.

However, in a LAN, one transmission path is usually shared by each node, so if each node is allowed to send outgoing calls through heat management, a situation may arise where two or more nodes are sending out calls at the same time.
A so-called "collision" phenomenon occurs in which data on the transmission path is interfered with. In contrast, in the token passing method, a communication control code called "token°", which is a command to transfer communication rights, is circulated within the network system, and this token is acquired (
Control is performed so that only the node that received the data (receiving data) acquires the right to transmit data, thereby preventing the occurrence of this collision phenomenon.

That is, a node acquires the transmission right only when it receives a token, and executes a series of communication processes at this time if there is a need for transmission. Then, when this transmission process is completed, or when the transmission process is not necessary, this token is passed to the next node (sent).

In this way, the token is passed to the next node one after another each time the transmission of the node that acquired the token is completed, but this method of passing is designed to circulate all the notes in the network, Each of the seven cards is given an equal chance of communication, that is, an equal communication service.

FIG. 4 shows the circulating state of nodes in this network system.

Regarding the token circulation method described above, there are two methods, the token bus method and the token link method, depending on the shape of the transmission path of the network.

In the token bus system, each node is connected to one common transmission path, and tokens circulate in the order of node addresses, for example, according to node addresses unique to each node. On the other hand, in the case of the token ring method, the transmission path connects only adjacent nodes, and when a token is received from one node, the token is sent to the other node. . In other words, tokens are physically passed to neighboring mates in order, but since the network is ring-shaped, they automatically circulate within the network. Both methods are the same in that the token circulates around all the mates in the network equally.

[Problems to be solved by the invention] In this way, each node can receive equal communication services by circulating the token, but for example, if a host computer or file device is connected to a node in the network, In these cases, the frequency of occurrence of these communication requests is extremely high compared to other general terminals.

Even in such cases, with conventional communication methods, the transmission right (token) is circulated only equally among all swords, which delays the transmission of necessary data and reduces the processing efficiency of the network system as a whole. There was a drawback that it could be stored away.

Measures to Solve the Problem J In order to solve the above problem, multiple transmission devices are connected via a communication medium, and only the transmission device that has acquired communication rights using a token, which is a communication rights transfer command, transmits data. In a priority communication control method of a network system in which the transmission device receives a communication priority, a setting means for setting a priority in communication of the own device to the transmission device, the priority set by the setting means and communication priority designation information in the received token. communication right acquisition determining means for determining whether or not to acquire communication rights based on the comparison result of the comparison means; comprising a changing means for changing communication priority designation information, the specific transmission device changing the communication priority designation information when receiving the token;
The opportunity for acquiring communication rights can be changed depending on the amount of communication of the transmission device, and the network system is configured with the transmission device having high efficiency according to the amount of communication.

[Operation] In a network system configured as described above, a token containing communication priority designation information is received, and only if the communication priority designation information of the own device is higher than this communication priority designation information, the information is acquired by a transmission request as a communication right acquisition. In other cases, even if the token is received, communication rights are not acquired, the token is circulated to the next node, and communication priority designation information is changed to a specific transmission device in the network system. This allows more communication rights to be transferred to devices that are used frequently.

"Embodiment" Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a node according to an embodiment of the present invention. In the diagram, 1 is a LAN network transmission path, 2 is a mate which is a transmission control device, and 3 is a block diagram of various computer equipment and office work connected to the node 2. It is a device.

The node 2 has a transmitting circuit 11/receiving circuit 12 that performs data communication with the transmission path 1, a token discriminating circuit 4 that determines whether or not the data received by the receiving circuit 12 is a token, and a token discriminating circuit 4 that controls the entire node and controls the outgoing data. A control unit (hereinafter referred to as CPU) that performs processing, decoding and decomposition of received data, and timing control of communication operations, etc.5. A memory circuit 6 that stores transmitted and received data, etc., and an interface circuit 7 with the host 3
, an address setting section 8 and a priority information holding section 9, each of which includes a switch that sets a unique address number for each node.
, priority information in the token and stored in the priority information holding unit 9.
It is comprised of a comparison circuit 10 that performs comparison with existing priority information, and a destination address discrimination circuit 13. The address value set in the address setting section 8 is read out by the CPU 5 and used as the destination address and source address during transmission and reception.

The data to be transmitted from the host 3 is temporarily stored in the memory circuit 6 in the node 2, and is appropriately formatted (packetized) as communication data, and the destination node address is set as the destination address value and the address setting circuit 8 After adding the set value of as the source address, the receiving circuit 11 receives the token addressed to the node, and the priority information of the information held in the priority information holding unit 9 of the own device is higher than the priority information of the token, Only when the transmission right is acquired can the signal be sent to the transmission path l via the transmission circuit 12.

On the other hand, the other node receives the communication data on the transmission path l, checks the destination address value in the received data in the destination address discrimination circuit 13, and checks the setting value of the address setting circuit 8 in the own node, that is, the value addressed to the own node. If it is determined that it is data, it is notified to the CPU 5, this data is taken into the eye node, and after some disassembly and editing processing is performed by the CPU 5, it is delivered to the connected host 3.

In addition, in the token passing method, all the data flowing on the transmission path l is not only the communication data between the hosts 3, but also the communication data between the CPU in each node such as a token and the CPU of the destination node. It also includes so-called communication control data.

Based on the above hardware configuration and the above-mentioned principle of token passing, each mate in the network receives and passes tokens to downstream nodes one after another, allowing communication to be performed using a single transmission path. be.

The structure of a transmission frame circulating through the network system of this embodiment is shown in FIGS. 2(A) and 2(B).

The tooth width 200 is a token frame, 201 is a source address (hereinafter referred to as SA), 202 is a destination address (hereinafter referred to as DA), 203 is a token code representing the token frame, 204 is a priority specification code, and 205 is a A transmission code 206 representing a data frame is transmission information.

Data transmission control in this embodiment will be explained below with reference to the flowchart in FIG.

First, in step Sl, it is monitored whether or not a transmission frame has been received from transmission path l. When a transmission frame is received, the process proceeds to step S2, and the destination address determination circuit 13 sets the DA 202 and address setting circuit 8 in the received frame. and the own node address value. If the two values do not match, and the transmission frame is not addressed to the 110th node, the process proceeds to step S3, where the received data frame is directly sent from the transmitting circuit 12 to the transmission path 1, and the process returns to step SL.

If the transmission frame is addressed to the own node, the process proceeds to step S4, where the token discriminating circuit 4 is activated and checks the transmission code area (203.degree. 205) in the received transmission frame to determine whether this is the token code 203 or not. In the case of receiving a token frame, the process advances to step S5, and the comparison circuit 10
is activated, and the priority designation code 204 is compared with the data held in the priority information holding unit 9. As a result, if the priority of the own node is higher, the process proceeds to step S7, and acquires the transmission right using the received token.In step S8, it is determined whether there is data to be transmitted from the host 3 or the own node, that is, a transmission request. Check whether there is a transmission request, and if there is a transmission request, step S9
The node address unique to the destination mate is set in DA202, the own node address set by address setting circuit 8 is set in 5A201, and then the transmission code 205 and transmission information 206 are set to generate data transmission frame 250. Then, in step SlO, this data transmission frame 250 is transmitted to the destination node according to a predetermined transmission control procedure. When the data transmission process is completed, in step Sll, the next node (downstream node) address to which the token should be passed is set in the DA 202, the self-mate address is set in 5A 201, the token code is set in 203, and the priority designation code is set in the DA 202. In 204, the priority designation sent to the own node is set as is, and this token frame 200 is generated, sent to the downstream node, and after transferring the transmission right, the process returns to step S1.

On the other hand, the token frame 200 received in step S6
If the priority specification code 204 of the node is higher than the priority held in the priority information holding unit 9 of the own node, the node is not allowed to acquire the transmission right, and the process proceeds to step S11, where it immediately generates a token frame. Send the token to the downstream node. If there is no request for transmission in step S8, the process similarly proceeds to step Sll, and the token is sent to the downstream node.

If the token has not been received in step S4, the process advances to step S20, and according to a predetermined transmission control procedure, the data transmission frame 250 addressed to the own device is received within the own node, and the transmission information received in step S21 is transferred to the host 3. It is checked whether the information should be sent to the host 3, and if it is the information that should be sent to the host 3, the process proceeds to step S22, where this information is slightly disassembled and edited, and then sent to the host 3 connected to this node, and the process proceeds to step S1. and prepare for the next data transmission.

If the data is not to be transmitted to the host 3, that is, if it is information for changing the content held in the priority information holding unit 9, which will be described later, the process advances to step 530, where processing corresponding to each received data is performed, and then step S1 Return to

Therefore, the priority specification information added to the token information is
In this case, it acts as a filter to select nodes that receive communication services.

The circulating state of the token in the above explanation is the fourth
The nodes 100 to 170 correspond to the nodes 2 shown in FIG. 1, respectively.

This notebook A100 is a node that can be called the master node of the network system, and the token frame 20
A priority designation code 204 of 0 is set, which is dynamically set in relation to the token circulation period.

The reproduction setting process of the priority designation code 204 of the node A 100 will be explained with reference to the token circuit diagram of FIG.

In this embodiment, the retention level of the priority information retention unit 9 of each node is set to the level shown below.

In Mate A100, the priority designation code 204 is set to 13'' in the first round of tokens, to ``2'' in the second round, to ``l'' in the third round, and again to ``1'' in the fourth round. 3n, and the above priority designation is periodically changed in accordance with the token circulation period.

Figure 5 (A) shows the node that acquires the transmission right at level "3," Figure 5 (B) shows the node that acquires the transmission right at level "2," and the node that acquires the transmission right at level "1" is shown in Figure 5 (A). In FIG. 5C, the nodes that acquire the transmission right at this time are indicated by diagonal lines.

As shown in the figure, the higher the number of levels, the higher the priority is given. In this way, a level 3 node (for example, node C120)
is compared to a node at level l (for example, node F150),
The right to transmit can be acquired three times as often, and a node at level 2 can acquire the right to transmit twice as often as a node at level l.

If the host connected to the mate is connected to a device with a high communication load, such as a host computer or a file device, by setting the node's priority to a high level, it will be able to communicate more easily than other nodes. It is possible to proceed with the processing significantly faster.

The priority information holding unit 9 of the node described above is constituted by a digital switch, and can be set to any level from level 1 to level 3 depending on the model of the connected host 3.

However, this priority information holding unit 9 does not necessarily set a fixed priority level using hardware, but can also set a dynamic priority level to an optimal value using software. For example, at the time of network startup, communication Once each node is started with the priority setting set to a specific value (default value), and when communication becomes possible, the specific node (for example, node C120) sends priority setting data as communication data to each node. and each node uses this sent priority setting data,
For example, it is stored in the priority information holding unit 9 configured with RAM. An example of this priority setting data transmission frame 300 is shown in FIG.

In the figure, 207 is a priority level transmission code indicating that the transmission frame is a priority information transmission frame, and 208 is priority information.

When this transmission frame is received, the priority information 208 sent as the process of step S30 in FIG.
It may be stored in the priority information holding unit 9 through the processing of the PU 5.

The specific node may be connected to a device having a non-volatile memory such as a file device as the host 3, and priority information for all seven nodes in the network may be registered in advance in this file device.

Figure 7 (A) shows an example of network priority setting at startup, and an example when the sending (setting) of the priority information 208 to each node has been completed and the priority resetting has been completed. FIG. 7(B) shows.

The set priority is shown within the frame of each node.
X is a default value which is a specific value. Figure 7 (A)
Based on the state shown in , optimal priority information is set for each node by taking into consideration the network traffic volume, etc.
The priority information shown in FIG. 886 can be set to the priority information shown in FIG.
This is done by sending 0, and the priority level is X1~
An example is shown in which X6 is set for each node.

Furthermore, in the above explanation, the priority specification code 204 in the token frame 200 that circulates within the network has been explained as an example in which only a specific code within the network can change and set it. It can be done not only by all nodes, but also by all nodes. In other words, from the time each mate powers on and stands up, each mate passes the token to the next node every cycle (or every multiple cycles) when it circulates to its own node. The priority designation code 204 in the token frame 200 is changed. In this case, as in the above embodiment,
Although it is not possible to perform unified control such that the entire network performs communication services for nodes with the same priority level or higher, at least from a node-to-node perspective, as shown in Figures 5 (A) to (C). Nodes with higher priority settings can acquire more transmission rights and more communication opportunities.

The right to change this priority designation code 204 may be equally owned by all nodes, or may be controlled so that only nodes with a specific priority level can do so.

FIG. 8 is a state diagram showing an example in which node A100 hands over the acquired token (i.e., transmission right) to a downstream node, and O
The node indicated by diagonal lines is the node that acquires the transmission right, and the node indicated by O is the mate that cannot acquire the transmission right even if it receives the token frame 200 and passes it to the next node as is.

In addition, the priority level in the diagram is Node D>Node C>Node B.

Every time the token frame 200 circulates, the node A 100 updates the priority designation m-)"2 in the token frame 200.
04 is periodically changed from a high level to a low level.

The advantage of this method is that the above embodiment is the only specific 7-
What used to depend on the code to change the priority designation information in tokens is now completely decentralized, which means that the network can be made more robust against failures.

Furthermore, in this embodiment, an example was explained in which the priority designation code 204 in the token frame 200 determines the priority, but this priority designation code is not defined in a separate area but is included in the token code 203. Then, a separate token code is assigned to each priority level as the token code 203, and the node that receives this token frame 200 decodes (deciphers) this token code and extracts the priority level. This reduces the amount of data transmitted over the network, making it possible to create a network system with high data transmission efficiency. In this way, it is sufficient that the entire token frame 200 includes information indicating some kind of priority designation.

Furthermore, although the above explanation has been made based on a token ring type network, the present invention is not limited to this, and transmission control may be performed using exactly the same processing even in a token bus type network configuration.

(Effects of the Invention) As explained above, according to the present invention, it is possible to efficiently allocate communication rights (transmission rights) in accordance with the communication amount of each transmission device constituting the network, and to achieve efficient transmission. A preferential communication control method for network systems can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram of nodes configuring a network system according to an embodiment of the present invention, and FIGS. 2(A) and (B)
is a transmission frame configuration diagram used in this embodiment, FIG. 3 is a data transmission control flowchart in a node of this embodiment, FIG. 4 is a token circulation state diagram in the network, and FIGS. 5 (A) to (C) are diagrams of this embodiment. The intent of each node in the example. FIG. 6 is a priority level transmission frame configuration diagram in another embodiment according to the present invention, FIG. FIG. 8 is a priority designation state transition diagram at node A according to still another embodiment of the present invention. In the figure, 1... Transmission path, 2,100-170... Node, 3... Host, 4... Token discrimination circuit, 5...
... CPU, 6 ... memory circuit, 8 ... address setting circuit, 9 ... priority information holding section, 10 ... comparison circuit, 11 ... reception circuit, 12 ... transmission circuit, 13.
...Destination address discrimination circuit, 203...Token code. 204...Priority designation code, 205...Transmission code, 207...Priority level transmission code, 208...
This is priority information. Patent applicant Canon Corporation Figure 6 Figure 7 (A) Figure 7 (''B) ?-38

Claims (1)

[Claims] (1) In a priority communication control method for a network system in which multiple transmission devices are connected via a communication medium and only the transmission device that has acquired the communication right by a token that is a communication right transfer command obtains the transmission right, the token is a holding unit that includes communication priority designation information and holds the communication priority of the own device in the transmission device; and comparing the priority held in the storage unit with the communication priority designation information in the received token. and communication right acquisition determining means for determining whether or not to acquire a communication right based on the comparison result of the comparison means, and further assigning communication priority to a specific device among the transmission devices in the token. A priority communication control method characterized by comprising a changing means for changing degree designation information.