JPS61285849A - Priority communication control system - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency by changing a transmitter through which a token is circulated. CONSTITUTION:A storage means 6 for storing information of transmitters constituting a network is provided, a token is circulated only to a transmitter having the priority more than the designated priority in 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 and the transmitter through which the token is circulated is change also. Thus, the opportunity of the communication right acquisition is changed in matching with the communication quantity of the transmitter to distribute efficiently the communication right (transmission right).

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 priority communication in 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, which is a communication right transfer command, has the right to transmit. In the control method, the detection means detects whether or not a token has been received a predetermined number of times in at least one of the plurality of transmission devices, and when the detection means detects reception of the token a predetermined number of times, a delegated optical address of the token is determined. The method includes a changing means for changing the address, and a token delegating means for delegating the token to a transmission device having an address changed by the changing means, making it possible to change the transmission device where the token circulates, and acquiring communication rights based on the communication volume of the transmission device. This invention discloses a technology that can efficiently allocate communication rights and improve transmission efficiency by making it possible to change opportunities for communication.

[Prior Art] A so-called local area network (LAN) is a network in which a large number of transmission devices (hereinafter referred to as notebooks) are connected together by sharing 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 160, which are nodes A to G constituting the LAN. Each node A to G (100 to 160)
There 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, each node usually shares one transmission path, so if each node were allowed to send outgoing calls without management, a situation would occur where two or more nodes would send out calls at the same time. The so-called “collision” is caused by interference of data on the transmission path.
``A phenomenon occurs.

For this reason, a communication control code called a "token" which is a communication rights delegation command is circulated within the network system, and control is performed so that only the node that acquires (receives) this token acquires the right to transmit data. , to prevent 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 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 seven nodes in the network. Each node in the network is given an equal chance of communication, that is, an equal 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 disappear at this node and cannot 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 spread out over a wide area, it is more convenient for users to start up nodes in the network partially rather than all at once. It is advantageous to be able to power down individual nodes of equipment that have finished their service. In these cases, the network will be operated while including some inoperable nodes.

Considering the above, it should be assumed that changes in the composition of operable and inoperable mates in the network can always occur.
Following this, each node in the network constantly monitors the status of the downstream node to which the primary token should be passed, and if it turns out that the downstream node has become inoperable,
It is necessary to immediately remove this node from the network configuration (and remove it from the token circulation ring), that is, perform degenerate operation, select another suitable node as the node to which the token should be transmitted 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 token ring method.

The transmission path connects only adjacent nodes, and when a token is received from one node, it primarily sends the token 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, has the transmission right. A priority communication control method for a network system that obtains the following: a detection means for detecting whether or not a token has been received a predetermined number of times in at least one of the plurality of transmission devices; A changing means for changing the delegated optical address of the token, and a token delegating means for delegating the token to a transmission device having an address changed by the changing means, so that the transmission device through which the token circulates can be changed, and the transmission device To provide a network system configuration in which opportunities for acquiring communication rights can be changed depending on the amount of communication, efficient allocation of communication rights can be performed, and transmission efficiency can be improved.

[Operation] 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 tokens are only sent to transmission devices that have a priority higher than the specified priority of the priority specification information in the token. By making the token circulate, and when the token has circulated a predetermined number of times, the priority designation information in the token is changed, and the transmission device through which the token circulates is also changed.

It is possible to provide a network system with high transmission efficiency that can change opportunities for acquiring communication rights according to the communication amount of the transmission device and efficiently allocate communication rights (transmission rights).

[Embodiment 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 node according to an embodiment of the present invention. In the figure, 1 is a LAN network transmission path, and 2 is a transmission system a.
Node 3, which is a device, is various computer equipment and office equipment connected to node 2.

The node 2 includes a transmitting circuit 11/receiving circuit 12 that performs data communication with the transmission path 1, and a token discriminating circuit 4 that determines whether the data received by the receiving circuit 12 is a token or not. A control unit (hereinafter referred to as CPU) 5 that performs overall control of the node, processing of transmitted data, decoding and decomposition of received data, timing control of communication operations, etc., a memory circuit 6 that stores transmitted and received data, etc. Interface circuit 7 between
．． An address setting section 8 and a priority information holding section 9, which are composed of switches and the like that set a unique address number for each node.
．． A comparison circuit 101 that compares the priority information in the token with the priority information held in the priority information holding unit 9, the destination address determination circuit 13, the address information of each constituent node of the network, and the priority held in each node. It consists of a network configuration table 14 that stores network information and the like.

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

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

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 address (hereinafter referred to as DA).
204 is a priority designation code, 205 is a transmission code representing a data frame, and 206 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 next node, the process returns to step S1 and preparations are made 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 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 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 second node, that is, if there is a transmission request. If there is a transmission request, in step S9, the node address unique to the destination node to which the data should be transmitted is set in DA202, and the own node address set by the address setting circuit 8 is set in 5A201.
a and set the transmission code 205 and transmission information 206,
A data transmission frame 250 is generated, and in step 310, 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 311, executes the priority designation process described later, and obtains the priority designation code and downstream node address to which the token should be sent, and then, in step 312, sends the own node address to 5A201. 203, set the destination node address and priority designation code determined by the priority designation process in step 511 in the node address DA 202 and priority designation code 204,
Generate this token frame 200 and send it to transmission path 1
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 token has been sent in error and acquisition of the transmission right is not allowed, and step 512 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 320, 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 521 is transmitted to the host node. If the information 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. Return to S1 and prepare 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 S30;
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 communication services.

Token priority specification process in the above explanation! @4
This will be explained below with reference to the flowchart shown in the figure.

First, in step S60, the token circulation number register in the memory circuit 6 is read, and in step S61, the register is read out.
0". If the register is "Oo", that is, if the token circulation is in the first order, step S6
2, the priority designation level is selected as °3", and in the subsequent step S63, among the nodes whose priority designation level is °3" or higher from the network configuration table 14, the priority designation level is selected as having a value equal to or higher than the own node address, and Select the node closest to the own node address as the downstream node. If the corresponding node does not exist, a node with the smallest node address and a priority designation level of "3" or higher is selected as a downstream node.

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".

If “3'', the token circulation number register is set to “O” in step 366 and the process ends.Step S6
If the token circulation number register is not 3'' at 5, the process is immediately terminated.

If the register is not "0" in step S61, the process advances to step S67, where it is checked whether the register is "1", and if the register is "1", that is, if the token circulation is in the second order, step Proceeding to S68, the priority designation level is selected to "-2", and in the following step 389, among the nodes whose priority designation level is "2'' or higher from the network configuration table 14, the priority designation level is selected to have a value equal to or higher than the own node address, And the node closest to the own node address is selected as the downstream node. If the corresponding node does not exist, the priority specified level is "" for the node with the smallest node address.
2'' or more nodes are selected as downstream nodes. Then, the process proceeds to step 364.

If the register is not "1" in step S67, that is, if the token circulation is in the third order, the process proceeds to step S70, where the priority designation level is added by °゛11, and a<step 5
In step 71, from the network configuration table 14, among the notes whose priority specification level is ``1n'' or higher, the node that has a value equal to or higher than the eye node address and is closest to the eye node address is selected as a downstream node.The corresponding node does not exist. In this case, the node with the smallest node address and the priority designation level of 1'' or higher is selected as the downstream node. The process then proceeds to step 364.

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.

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 level "'l" Notes that acquire the transmission right in the case of , are shown with diagonal lines in FIG. 5(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)
compared to a level 1 node (e.g. 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 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 mate to a high level, the communication 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 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 software6. For example, at the time of network startup, communication Each node is started once with the priority setting set to a specific value (default value). Then, when each node becomes able to communicate, a specific mate (for example, node C120) sends priority setting data as communication data to each node, and each node uses the sent priority setting data to For example, it may be stored in the priority information holding unit 9 configured with RAM.

The above-mentioned 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 priority information for all nodes in the network is registered in this file device in advance. good.

FIG. 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 the latter 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.

From the state shown in FIG. 7(A), optimal priority information can be set for each node by taking into consideration network traffic volume, etc., and set to the priority information shown in FIG. 7(B), for example. This setting is performed, for example, by the node Cl2O connected to the file device as the host 3, transmitting the transmission frame 300 shown in FIG. 6, and an example is shown in which priority levels x1 to x6 are set for each node. ing.

In addition, in this embodiment, if the priority of all nodes is set to the highest level, the token will uniformly tour all the 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 312 in FIG.

First, in step 340, a token is sent, and in step 34
In step 1, check whether the token delegation was performed normally.

The means for identifying this varies depending on the transmission control procedure of each network.

For example, A is an acknowledgment at the node that received the token.
This is done by returning a CK response, or by the receiving node starting a new communication operation and then determining that the source address of the communication data sent out to the 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 has been sent twice in step S42, the process proceeds to step S43. This is to deal with the case where the other node to which the token has been passed suddenly goes down (failure or power is turned off). This is to find a new node to which the token should be transferred.

In step S43, the downstream node address is set to the set address of the second node, regardless of the previous downstream node address, and in the subsequent step S44, this downstream node address is incremented by one, and in step S45, this downstream node address is set as the destination node address. Priority level as address “
The token is sent as "l" (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 548, assuming that the other node is an inoperable (communicating) node, and the downstream node address value is the maximum specified by the network. It is checked whether the address value is the same or not, and 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 347 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 advances from step 546 to step S49.

Therefore, this operation is stopped, the downstream node address value at that time is stored in the network configuration table 14, and the address value at that time is used as the downstream node address from now on.

Since the processing of the above operations takes time, this processing is not performed every time, but is performed only at fixed intervals.
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 to achieve this, it monitors the transmission frames on the transmission path l. For example, if the node address is 5A201, DA202 In the case where the token code 203 is detected, data may be immediately sent onto the transmission path, causing a "collision" with the token frame 200, and the processing from step S43 in FIG. 9 onward 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 performs communication services for nodes with the same priority level or higher, but at least from a node-to-node perspective, As shown in FIGS. 5(A) to 5(C), the node with a higher priority setting can acquire more transmission rights and one communication opportunity.

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.

One example of this synchronization means is global addressing (i.e., global addressing, which is provided in many networks).
There is a method in which a specific node in the network sends a communication control command to initialize the cyclic count value of a token by using a means capable of simultaneously broadcasting to all nodes in the network. Each node in the network that receives this communication control command initializes the cycle cycle count value of the token that was previously managed by the node to a unified specific value.

These processes are controlled to be included in the process of step S30 in FIG.

As a result, all nodes operate based on the same token cycle period value from subsequent token cycles, so communication services with uniform priority can be performed in the network.
It becomes like being called.

Furthermore, although the above description 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 or 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.

[Effect of the Invention J As explained above, according to the present invention, the opportunity to acquire communication rights is changed according to the communication volume of each transmission device configuring 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.

Furthermore, it is possible to provide a priority communication control method that allows the network system to be immediately rebuilt even if there is a change in the constituent nodes in the network system.

[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 general data transmission control flowchart in a node of this embodiment, FIG. 4 is a priority designation processing flowchart in this embodiment, and FIGS. C) is a transmission right acquisition state diagram of each node in this embodiment, FIG. 6 is a flowchart of network reconfiguration processing in this embodiment, and FIGS. 7(A) and CB) are each of other embodiments according to the present invention. A state diagram of priority information setting in a node, and FIG. 8 is a token cyclic transition diagram of a token passing method. FIG. 9 is a flowchart of network reconfiguration processing in this embodiment. In the figure, l...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 unit, 10...Comparison circuit, 11...Receiving circuit, 12...Transmitting circuit , 13
. . . Destination address determination circuit, 14 . . . Network configuration table. 203...Token code, 204...Priority designation code, 205...Transmission code. Figure 2 (A) District 2 (B) Figure 3 Figure 7 (B) Cause 8 District 9

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 devices at least one of
a detecting means for detecting whether or not a token has been received a predetermined number of times; a changing means for changing the delegated optical address of the token when the detecting means detects reception of the token a predetermined number of times; 1. A priority communication control system, comprising: token delegation means for delegating a token to a transmission device having an address, and making it possible to change the transmission device through which the token circulates.