JPS61285848A - Priority communication control system - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency by changing the opportunity of communication right acquisition depending on the communication quantity of a transmitter. CONSTITUTION:Each transmitter constitution a network is provided with a storage means 6 storing the information of a transmitter constituting the network. Then a token is circulated only to a transmitter having a priority more than the designated priority of the priority designation information in the token and when the token is circulated for a prescribed number of times, the priority designation information in the token is changed to change the transmitter through which the token is circulated. Thus, the opportunity of the communication right acquisition is changed in matching with the communication quantity of the transmitter and the communication right (transmission right) is shared efficiently to obtain the network system with excellent transmission efficiency.

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 delegation of communication rights using communication priority designation information in a token.

"Summary of the Disclosure" This specification and drawings describe - a 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 delegation command can obtain the transmission right. In the priority communication control method, a detection means detects whether or not a token has been received a predetermined number of times in some of the plurality of transmission devices; A network system comprising a changing means for changing an address, a token delegating means for delegating a token to a transmission device having an address changed by the changing means, and a setting means for setting the number of times of detection by the detecting means to a specific value. The specified transmission device is further provided with an output means for outputting the setting value of the setting means to another transmission device, and the transmission device where the token circulates is set as a transmission device with a communication priority higher than a certain level, and communication is performed according to the communication amount of the transmission device. Right 11! The present invention discloses a technology that can efficiently allocate communication rights and improve transmission efficiency by making it possible to change the opportunity to gain.

E. Prior Art A so-called LAN is a so-called local area network in which a large number of transmission devices (hereinafter referred to as nodes) are connected together using a single transmission path, and data communication is performed between these nodes.
' is popular.

An example of the system configuration of this LAN is shown in FIG.

In the figure, reference numeral 1 indicates transmission lines 100 to 180, which are nodes A to G constituting the LAN. Each node A to G (100-160)
are hosts A to G (2) that process transmission information, respectively.
00 to 260) are connected.

Among various communication methods in a LAN, the token passing method is particularly superior in that it can equally provide communication services to all nodes even when the network is in a high traffic state.

However, in a bus-based LAN, one transmission path is usually shared by each mate, so if each node is allowed to send outgoing calls without management, a situation may occur where two or more nodes are sending out calls at the same time. Interference of data on the transmission path, so-called ``collision''
``A phenomenon occurs.

For this reason, a communication control code called one token pa, which is a communication right delegation command, is circulated within the network system, and control is performed so that only the node that acquires (receives) this token acquires the transmission right to transmit data. The occurrence of this collision phenomenon is prevented.

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 processing is completed or when transmission processing 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. 8 shows the circulation status of tokens in the network system shown in FIG. 6.

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.

Now, as a matter of course, in a network system, some nodes become inoperable due to power outage, failure, or the like.゛If one node that makes up the network system goes down, the tokens will disappear at this mate and will no longer be sent to the next node. Therefore, if things continue as they are, the tokens will not be circulated, and a serious situation will occur in which communication will be impossible at any node in the network.

Furthermore, in a network, there are circumstances in which it is impossible to deny the existence of inoperable nodes even though they are not out of order. In other words, since the devices and offices connected to a network are widely distributed, it is more convenient for users to start up nodes in two networks partially rather than all at once. It is more convenient to be able to power down individual nodes of devices that have finished their work. In these cases, the network will be operated while including some inoperable nodes.

Considering the above, it is inevitable that changes in the configuration of operable and inoperable nodes within the network will always occur.
Following this, each node in the network constantly monitors the status of the downstream node to which it should pass the token next, and if it is determined that the downstream node has become inoperable, it will immediately transfer this node to the network. In other words, it is necessary to select another appropriate node as the node to which the token should be passed from now on, and switch to this node.

Furthermore, if a node with an address value intermediate between the node that has previously passed tokens and its own node becomes operational and is ready to enter the network (receive tokens), it will receive tokens. It is necessary to switch the downstream node to which it should be passed to this new 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 then 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.

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.

Measures for Solving Problem L] In order to solve the above problem, a plurality of transmission devices are connected via a communication medium, and communication rights are granted using a token, which is a communication rights delegation command that includes communication priority designation information. A network system in which only the acquired transmission device obtains the transmission right, and detecting means for detecting whether or not some of the plurality of transmission devices have received a token a predetermined number of times; Upon detection, a changing means for changing the delegated optical address of the token, a token transfer means for transferring the token to a transmission device having the address changed by the changing means, and a setting for setting the number of times of detection by the detecting means to a specific value. and a specific transmission device in the network system further includes output means for outputting the setting value of the setting means to another transmission device, and the transmission device where the token circulates is set as a transmission device with a communication priority higher than a certain level. , the opportunity to acquire communication rights can be changed depending on the communication amount of the transmission device. To provide a network system configuration that can efficiently allocate communication rights and improve transmission efficiency.

[Function] Each transmission device that makes up the network is equipped with a storage means for storing information about the transmission devices that make up the network, and the token is sent only to the transmission device that has a priority higher than the specified priority of the priority specification information in the token. By circulating the token and changing the priority designation information in the token when the token has circulated a predetermined number of times, and also changing the transmission device that the token circulates, the opportunity to acquire communication rights is changed according to the communication volume of the transmission equipment. Therefore, it is possible to provide a network system with high transmission efficiency that can efficiently allocate communication rights (transmission rights).

[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, l is a LAN network transmission path, 2 is a node that 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 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) 5 that performs processing, decoding and decomposition of received data, timing control of communication operations, etc., 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.
, the priority information in the token and the priority information holding unit 9 “
It is composed of a comparison circuit 10 that performs a comparison with the priority information held by the network, a destination address discrimination circuit 13, a network configuration table 14 that stores address information of each constituent node of the network, and priority information held at each node. ing. The address value set in the address setting section 8 and the node information in the network configuration table 14 are read 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 from the network configuration table 14 is converted into the destination address. After adding the setting value of the address setting circuit 8 as the source address, the receiving circuit 11 receives the token addressed to the eye node, and based on the priority information, the information held in the priority information holding unit 9 of the own device is has a high priority and can be sent to the transmission path l via the transmission circuit 12 only when the transmission right is acquired.

On the other hand, the other mate receives the communication data on the transmission path 1, checks the destination address value in the received data in the destination at trace determination 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 imported into the eye node, and after some decomposition 1 editing processing is performed by the CPU 5,
Deliver to the connected host 3.

In addition, in the token passing method, all the data flowing on the transmission line 1 is not only the communication data between the hosts 3, but also the communication data between the CPU in each 7-card such as a token and the CPU of the other party. 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 mates one after another, thereby performing communication using a single transmission path. be.

The network system configuration of this embodiment will be described below as the configuration shown in FIG.

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), and 203 is a token frame t-table t.
)-kun code, 204 is a priority designation code, 205 is a transmission code representing a data frame, and 20B is transmission information.

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

First, in step S1, it is monitored whether or not a transmission frame is received from the transmission path 1. 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 own node, the process returns to step Sl and prepares to receive the transmission frame addressed to the next node.

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 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, if there is a request for transmission. If there is a transmission request, in step S9, the node address unique to the source node to which the data should be transmitted is set in DA202, and the own node address set by address setting circuit 8 is set in 5A201.
Next, set the transmission code 205 and transmission information 206,
A data transmission frame 250 is generated, and in step 510, this data transmission frame 250 is transmitted to a destination node according to a predetermined transmission control procedure.

When the data transmission process is completed, the process proceeds to step Sll, executes the priority designation process to be described later, and obtains the priority designation code and downstream node address to which the token should be sent, and then, in step S12, sends the own node address to 5A201. , set the token code in 203, and set the node address DA202. and the priority designation code 204 is set with the destination node address and priority designation code determined by the priority designation process in step 311,
This token frame 200 is generated and transferred to the transmission path l.
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 eye node is higher than the priority held in the priority information holding unit 9 of the eye node, the token has been sent in error and acquisition of the transmission right is not allowed, and the token is sent in step S12. immediately generates a token frame and sends the token to the downstream node. If there is no transmission request in step S8, the process advances to step Sll and the token is sent to the downstream node.

If the token is not received in step S4, the process proceeds to step S20, in which the data transmission frame 250 addressed to the own device is received in the eye node according to a predetermined transmission control procedure, and the transmission information received in step 321 is transmitted to the host node. Check whether the information should be sent to the host 3, and if it is the information to be sent to the host 3, proceed to step S22, and after disassembling and editing this information to some extent, send it to the host 3 connected to this notebook, and then proceed to step S22. It returns to Sl and prepares for the next data transmission.

If the data is not to be sent to the host 3, that is, if it is communication data between nodes, the process advances to step 530;
Processing corresponding to each received data is performed, and then the process returns to step S1.

This inter-node communication data includes, when each node newly joins the network, the node address of the joining node sent by group broadcast communication, priority designation information held in the node, etc. In this case, this priority designation information is stored in the network configuration table 14.

Also included is a request for transmission of network configuration table information from a newly joining node.

In this way, the priority designation information added to the token information serves as a filter for selecting nodes that receive one communication service.

The token priority designation process in the above description will be described below with reference to the flowchart of FIG.

First, in step S60, the token circulation number register in the memory circuit 6 is read, and in step 561, the register is “
Check whether the register is "0".Here, if the register is "0",
That is, if the token circulation is in the first order, step 362
In step S63, the priority designation level is selected as 3', and in the following step S63, among the nodes whose priority designation level is "3" or higher from the network configuration table 14, the node whose priority designation level is "3" or higher has a value equal to or higher than its own node address, and which Select the node closest to the address as the downstream node. If the corresponding node does not exist, the priority specification level is °゛3° for the node with the smallest node address.

The above nodes are selected as downstream nodes.

Then, in step S64, the token circulation number register is incremented by one, and in step S65, it is checked whether the token circulation number register is '3''.

3", the token cycle number register is set to "O" in step 366, and the process ends. If the token cycle number register is not '3' in step S65, the process ends immediately.

If the register is not "0" in step S81, the process advances to step S67 to check whether the register is "1" or not. If the register is "1" here, that is, if the token circulation is in the second order, step In step S69, the priority designation level is selected as "2", and the priority designation level is determined to be "2" or higher from the network configuration table 14 in step S69. And the node closest to the own node address is selected as the downstream mate.If the corresponding node does not exist, the priority specification level is "2" for the node with the smallest node address.
The above nodes are selected as downstream nodes. The process then proceeds to step 564.

In step 587, if the register is not 1'', that is, if the token circulation is in the third order, the process advances to step 570;
The priority specification level is selected as 1”, and the following step 571
From the network configuration table 14, among the nodes whose priority designation level is "1" or higher, a node having a value greater than or equal to its own node address and which is closest to its own node address is selected as a downstream node. If the corresponding node does not exist, the node with the smallest node address and the priority designation level "1'1" is selected as the downstream mate. The process then proceeds to step 584.

Token circulation according to the present embodiment through the above processing is shown in FIGS. 5(A) to 5(C), taking as an example the case where the network system configuration is shown in FIG. 6.

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

The node that acquires the transmission right at level "3" is shown in Figure 5 (A), the node that acquires the transmission right at level "2" is shown in Figure 5 (CB), and the node that acquires the transmission right at level "1" is shown in Figure 5 (A). The nodes that acquire the transmission right are indicated by diagonal lines in the 51st ff7 (C).

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)
can acquire the transmission right three times more frequently than a level L node (e.g., node F 150), and a level 2
A node at level 1 can acquire the transmission right twice as often as a node at level l.

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, the priority of the mate is set to a high level, so the communication speed is lower than that of other nodes. It is possible to proceed with the processing significantly faster.

The above-mentioned priority information holding section 9 of the seventh mode 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, at the time of network startup, Each node is started once by setting the communication priority to a specific value (default value). and,
When each node becomes able to communicate, a specific node (for example, node C120) sends priority setting data as communication data to each node, and each node receives the sent priority setting data. may be stored in the priority information holding unit 9 configured with RAM, for example.

The above specific node (node C120) is set as host 3 as a mate connected to a device having nonvolatile memory such as a file device, and priority information for all nodes in the network is registered in this file device in advance. good.

Figure 7 (A) shows an example of the network priority setting at startup, after which the sending (setting) of the priority information 208 to each 7-board is completed and the priority resetting is completed. An example 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.

From the state shown in FIG. 7(A), optimal priority information may be set for each node by taking into account the amount of network traffic, etc., and set to the priority information shown in FIG. 7(CB), for example. This setting is performed, for example, by node Cl2O, to which the file device is connected as host 3, transmitting the transmission frame 300 shown in FIG. There is.

In addition, in this embodiment, if the priority of all swords is set to the highest level, the token will uniformly tour all nodes during all rounds, and the same control as the conventional token tour can be performed.

In the above explanation, an example was explained in which the next node to be given the token is changed every cycle when the token circulates to the eye node, and the priority specification code 204 in the token frame 200 is changed. , may be controlled to be changed every multiple cycles.

On the other hand, the following describes the network reconfiguration when a new node joins the network, or when a node that was part of the network drops out of the network due to power stage failure, etc., with reference to the flowchart in Figure 9. Explain.

This process is performed simultaneously with the token sending process of step S12 in FIG.

First, in step 540, a token is sent, and in step S4
In step 1, check whether the token delegation was performed normally.

The means for identifying this differs depending on the transmission control procedure of each network, but for example, the receiving node returns an ACK response as an affirmative response when receiving the token, or the receiving mate starts a new communication operation and This is done by determining that the source address of the communication data sent to transmission path 1 is this downstream node address.

If the token has been successfully transferred, the process ends here.

If the token is not successfully transferred in step S41, it is checked in step S42 whether or not the token has been transmitted for the second time, and if it is the first time, the process returns to step S40.
Execute token resend processing. If the token is sent twice in step S42, the state
This is to deal with the case where the other node to which the token has been handed suddenly goes down (failure or power failure), and the purpose is to search for a new node to which the token should be transferred.

In step 343, the downstream food address is set to the set address of the own node, regardless of the previous downstream node address, and in the subsequent step S44, this downstream note address is incremented by one, and in step S45, this downstream node address is set as the destination address. Priority level as address “
The token is sent as 1'' (or as
It is similar to

If the token is not successfully sent to the downstream node (if the transmission fails), the process proceeds to step 348, assuming that the other node is an inoperable (communication) node, and the downstream node address value is added to the network. If it is not the maximum address value, the process returns to step S44, the downstream node address value is again incremented by one, and token transmission is attempted using this new downstream node address value as the destination address.

In this way, the address values are gradually added and a token is attempted to be sent to the node corresponding to the address value, and this operation is repeated until a token is received by any node.

If the token transfer is not successful even if the added address value reaches the maximum address value defined in the network, the process proceeds from step S47 to step 548, and the downstream node address value is determined in the network. The process returns to step S45 as the minimum node address value. Thereafter, the token receiving, passing, and address value addition operations are repeated.

If the token transfer is successful, the process proceeds from step S46 to step 349, where this operation is stopped, the downstream node address value at that time is stored in the network configuration table 14, and from now on, the downstream node address value at that time is Use node address.

Since the processing of the above operations takes time, this processing is not performed every time, but is performed only at each bar cycle.
A new downstream node may be determined from among the nodes stored in No. 4.

In addition, a node newly joining the network configuration needs to have its own node circulate tokens, and in order to achieve this, it monitors the transmission frames on transmission path 1. For example, if the own node address is 5A201, DA202 In the case where the token code 203 is detected, data may be immediately sent onto the transmission line, causing a "collision" with the token frame 200, and the processing from step 343 onward in FIG. 9 may be executed.

In addition, if each node of the network is powered on at different times and starts up in an inconsistent state, the count value of how many times the token is currently circulating around the network will be a different value. . In this case, if the above embodiment is executed, it is not possible to perform unified control such that the entire network provides communication services for nodes with the same priority level or higher, but at least from a node-to-node perspective - 1. As shown in FIGS. 5(A) to 5(C), nodes with higher priority settings can acquire more transmission rights and have more communication opportunities.

Furthermore, in such a network, if a synchronization means is added to make the count value of the token cycle period of all nodes the same, it is possible to provide uniform priority services as a network.

An example of this synchronization means is global addressing (i.e., a means for simultaneously broadcasting information to all nodes within the network), which is provided in many networks.
There is a method in which a specific node in the network, for example, node Cl2O, sends a communication control command to initialize the cyclic count value of the token.

The above specific node (node C120) is assumed to be a host 3 connected to a device having non-volatile memory such as a file device, and synchronization information for all nodes in the network is registered in this file device in advance. good.

Then, the synchronization communication control command frame is controlled to be sent to all nodes of the network at fixed time intervals or every fixed number of cycles of the token.

FIG. 10 shows a transmission frame of this communication control command.

In the figure, 210 is a global address GA, 211 is a control code indicating that it is a communication control command transmission frame, and 21
2 is synchronization designation information indicating priority information to be synchronized and a token circulation register value to be synchronized.

-1 Each node in the network that receives the communication control command transmission frame initializes the cyclic cycle count value of the token that was previously managed by the node to a unified specific value according to the specification, and sets the priority information to the specified value. Set to .

These processes are controlled to be included in the process of step 530 in Figure ff13.

As a result, all nodes operate based on the same token cycle period value from the subsequent token circulation, so that communication services with uniform priority can be provided in the network.

Furthermore, although the above explanation has been made based on a token bus type network, the present embodiment is not limited to this, and can also be applied to a token ring type network configuration.

As explained above, according to this embodiment, token transfer can be performed reliably in any case, and even if token transfer cannot be performed normally, the network can be regenerated with almost no loss in data transmission efficiency. Can be constructed.

"Effects of the Invention" As explained above, according to the present invention, opportunities for acquiring communication rights are changed according to the communication volume of each transmission device making up the network, and communication rights (transmission rights) are efficiently distributed. It is possible to provide a priority communication control method for a network system with high transmission efficiency.

[Brief explanation of drawings]

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 general data transmission control flowchart in the 7th mode of this embodiment, and Figure 4 is a flowchart of general data transmission control in the 7th mode of this embodiment. Flowchart of priority designation processing. FIGS. 5(A) to (C) are state diagrams of acquisition of transmission rights for each mate in this embodiment. FIG. 6 is a flowchart of network reconfiguration processing in this embodiment. FIG. 7(A) , (B) is a priority information setting state diagram at each node in another embodiment according to the present invention, and FIG. 8 is a token cyclic transition diagram of a token passing method. FIG. 9 is a flowchart of network reconfiguration processing according to this embodiment, and FIG. 1O is a diagram showing the configuration of a communication control command transmission frame according to this embodiment. In the figure, 1... transmission line, 2. Zoo ~ 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, 14...Network configuration table, 203...Token code, 204...
・Priority designation code, zos...transmission code, 210
. . . Global address, 212 . . . Synchronization designation information. Figure 32 Figure 3 Figure 5 (A) Section 5 Figure CB) Figure 6 Figure 8 "Figure S9

Claims (1)

[Claims] (1) In a priority communication control method for a 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 obtains the transmission right, the plurality of transmission detecting means for detecting whether a token has been received a predetermined number of times in some of the devices; a changing means for changing the delegated optical address of said token when said detecting means detects reception of a predetermined number of tokens; and said changing means. and a setting means for setting the number of times of detection by the detection means to a specific value. A priority communication control system, comprising: an output means for outputting a setting value of the setting means, and a transmission apparatus through which a token circulates is a transmission apparatus having a communication priority higher than a certain level.