JPS61285845A - Priority communication control system - Google Patents

Abstract

PURPOSE:To improve the processing efficiency by providing a setting means for setting the priority in the communication of the own equipment, a comparison means for comparing communication priority designation information in a token and a communication right acquisition deciding means for deciding the communication right to a transmitter. CONSTITUTION:A node 2 consists of an address setting device 8 comprising a switch setting an address number inherent to each node, a priority information storage section 9, a comparison circuit 10 comparing the priority information in the token with the priority information stored in the section 9 and a destination address discrimination circuit 13. In other nodes, communication data in a transmission line 1 is received, a destination address in the reception data is checked by a destination address discrimination circuit 13 and the fact that the setting value of the address setting circuit 8 in the own node, that is, the data addressed to the own node exists is judged, it is informed to a CPU5, the data is fetched in the own node, after slight analysis and editing are applied by the CPU5, the result is delivered to the connected host 3.

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 the 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 by a token that is a communication right transfer command can obtain the transmission right. In the communication control method, a setting means includes communication priority designation information in the token and sets a priority for communication of the own device in the transmission device, and a setting means that includes communication priority designation information in the token and sets a priority in the communication of the own device to the transmission device; By providing a comparison means for comparing the communication priority designation information and 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, the communication amount of the transmission device can be reduced. The present invention discloses a technology that can efficiently allocate communication rights according to the situation and improve transmission efficiency.

[Background Art] A large number of transmission devices (hereinafter referred to as nodes) are connected together by sharing one transmission path, and data communication is performed between these nodes. So-called local area network "LAN"
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 calls without management, a situation will occur where two or more nodes will send calls at the same time.
Interference occurs in data on the transmission path. A so-called "collision" phenomenon occurs.In contrast, in the token passing method, a communication control code called a "token" that is a command to transfer communication rights is circulated within the network system, and this token is acquired (
This collision phenomenon is prevented by controlling so that only the /- card that received the data acquires the right to transmit the data.

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 (sent) to the next node.

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 through all nodes in the network. Each node is given an equal chance of communication, that is, a communication service.

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

Regarding the token circulating method described above, there are two methods, the token bus method and the token ring 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 system, the transmission path connects only adjacent nodes, and when a token is received from one node, the token is first sent to the other node. In other words, tokens are physically passed to neighboring nodes sequentially, but since the network is ring-shaped, they automatically circulate within the network. Both methods are the same in that the token circulates evenly around all nodes in the network.

[Problem 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 nodes, 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.

[Means for solving the problem] In order to solve the above problem, 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, transmits data. In a priority communication control method of a network system in which the transmission device receives a communication priority, the transmission device includes a setting means for setting a priority in communication of the own device, and a priority set by the setting means and a communication priority in the received token. a comparison means for comparing the specified information;
A network system is configured by a transmission device including communication right acquisition determining means for determining whether or not to acquire a communication right based on the comparison result of the comparison means.

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 and the token is circulated to the next 7-card, making it possible to transfer more communication rights to devices that transmit frequently. It is said that

LEmbodiment J Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

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

The node 2 includes a transmitting circuit 11/receiving circuit 12 . that performs data communication with the transmission path l. A token discriminating circuit 4 determines whether the data received by the receiving circuit 12 is a token, a control unit (hereinafter referred to as CPU) performs overall control of the node, processing of transmitted data, decoding and decomposition of received data, 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.
, a comparison circuit 101 which compares the priority information in the token with the priority information held in the priority information holding section 9, and a destination address determination circuit 13. Address setting section 8
The address set is read by the CPU 5 and used as the destination address and source address during transmission and reception. Data to be transmitted from the host 3 is temporarily stored in the memory circuit 6 in the node 2, After proper formatting (packetization) as communication data and adding the destination node address as the destination address value and the setting value of the address setting circuit 8 as the source address, the receiving circuit 11 sends a token addressed to the own node. It can be sent to the transmission path 1 via the transmission circuit 12 only when the information held in the priority information holding unit 9 of the own device has a higher priority than the priority information and the transmission right is acquired. .

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 target node. If it is determined that it is data, it is notified to the CPU 5, this data is taken into its own node, and after some disassembly and editing processing is performed by the CPU 5, it is delivered to the connected host 3.

In the token passing method, all the data flowing on the transmission path 1 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 other node. It also includes so-called communication control data.

Based on the above hardware configuration and the principle of token passing mentioned above, each node in the network receives and passes tokens to downstream nodes one after another, thereby performing communication 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).

In the figure, 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.

The data transmission control of this embodiment will be explained below with reference to the flowchart of FIG.

First, in step SL, it is monitored whether or not a transmission frame is received from the 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, that is, if the transmission frame is not addressed to the eye node, the process proceeds to step S3, where the received data frame is sent as it is from the transmission circuit 12 to the transmission line 1, and the process returns to step Sl.

In the case of the transmission frame addressed to the second 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 reception of a token frame, the process advances to step S5, and the comparison circuit lO
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 host 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 its own node, that is, if there is a transmission request. Check to see if there is one, and if there is a transmission request, send a unique food address to the destination mate to the DA 202 in step S9.
The own node address set by the address setting circuit 8 is set to 5A201, and then the transmission code 2
05, the transmission information 206 is set, a data transmission frame 250 is generated, and in step SIO, this data transmission frame 250 is transmitted to the transmission source 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 own note 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, set the priority specification sent to the eye note as is,
After this token frame 200 is generated, sent to the downstream node, and the transmission right is transferred, the process returns to step S1.

Itto, 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 transmission request in step S8, the process similarly proceeds to step S11, and the token is sent to the -downstream note.

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 subjected to some decomposition and editing, and then sent to the host 3 connected to this node, and 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 S30, 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 will serve as a filter for selecting nodes that receive one communication service.

The circulating state of the token in the above explanation is the fourth
The nodes 100-170 correspond to nodes 2 shown in FIG. 1, respectively. This node A 100 is a node that can be called the master node of the network system, and the priority designation code 2 in the token frame 200 is
04, 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 the notebook A100, the priority specification code 204 is set to °3 in the first round of tokens, to "2°' in the second round, to °ll in the third round, and again in the fourth round. Set to °3″,
The above priority specification is changed periodically according to the token rotation period.

Figure 5 (A) shows the node that acquires the transmission right when the level is "3", Figure 5 (B) shows the node that acquires the transmission right when the level is "2", and the node that acquires the transmission right when the level is "2" is shown in Figure 5 (B). 5(C), the nodes that acquire the transmission right in the case of `` are shown with 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)
compared to a level 1 node (e.g. node F150),
The right to transmit can be acquired three times as often, and a level 2 node can acquire the right to transmit twice as often as a level 1 node.

If the host connected to the node is connected to a device with a high communication load, such as a host computer or a file device, by setting the priority of the node to a high level, it is possible to This makes it possible to significantly speed up communication processing.

The priority information holding unit 9 of the node described above is constituted by a DIP 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 by hardware, but can also dynamically set the priority level to an optimal value by software. For example, when starting up the network, one communication Change the priority setting to a specific value (default Hf)
1), each node is started up once, and when communication becomes possible, a specific node (for example, node C120) sends priority setting data as communication data to each node, and each node receives this transmission. The received priority setting data is stored in a priority information holding unit 9 configured of, for example, a 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 nodes in the network may be registered in advance in this file device.

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

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 can be set to the priority information shown in Figure CB).This setting is performed, for example, by the node Cl2O connected to the file device as the host 3, by transmitting the transmission frame 300 shown in Figure 6, and the priority level is xx-xs
is set for each note.

Furthermore, in the above explanation, the priority specification code 204 in the token frame 200 that circulates within the network has been described as an example in which only a specific node within the network can change and set it. It is not limited to this, but it can be done by all nodes. In other words, each node passes the token to the next node every cycle (or every multiple cycles) when the token circulates to its own node from the time it powers on and starts up. 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-sode perspective, as shown in Figures 5 (A) to (C). As such, nodes with higher priority settings can acquire more transmission rights and one communication opportunity.

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 the node A100 hands over the acquired token (i.e., the transmission right) to the downstream node;
The nodes indicated with diagonal lines are the nodes that acquire the transmission right, and the nodes indicated with circles are nodes that cannot acquire the transmission right even if they receive the token frame 200 and pass it on to the next node as is.

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

The node A 100 updates the priority designation code 20 in the token frame 200 every time the token frame 200 circulates.
4 shows an example in which the signal 4 is periodically changed from a high level to a low level.

The advantage of this method is that it is completely decentralized, unlike the previous embodiment, which relied only on a specific node to change the priority specification information in the token. The point is that it can be made into a strong network.

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, efficient communication rights (
It is possible to provide a priority communication control method for a network system with high transmission efficiency.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of nodes configuring a network system according to an embodiment of the present invention. Figures 2 (A) and (B) are transmission frame configuration diagrams used in this embodiment, Figure 3 is a data transmission control flowchart in the nodes of this embodiment, Figure 4 is a token circulation state diagram in the network, and Figure 5. (A) to (C) are state diagrams of acquisition of transmission rights for each 7-rd in this embodiment. Figure 6 is a configuration diagram of a priority level transmission frame in another embodiment according to the present invention, and Figures 7 (A) and (B) are state diagrams of priority information setting at each node in another embodiment according to the present invention. FIG. 8 is a priority designation state transition diagram at node A in yet 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.
...Priority information. Figure 5 (A) Figure 5 (B) Figure 5 (C) Figure 6 Stop Figure 7 (A) R; S7 Figure (B) Stop Figure 8

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 setting means that includes communication priority designation information and sets a priority for communication of the own device in the transmission device, and a comparison between the priority set by the setting means and the communication priority designation information in the received token. 1. A priority communication control system comprising a comparison means and a communication right acquisition determining means for determining whether or not to acquire a communication right based on the comparison result of the comparison means.