JPS6211335A - Data transmission control system - Google Patents

Abstract

PURPOSE:To attain sharing of a transmission right with excellent transmission efficiency by transferring a token to a transmitter having the maximum transmission waiting information quantity to each stored transmitter to allow the number of times of acquisition of the transmission right to correspond to the transmission request quantity. CONSTITUTION:A token addressed to the own node is received by a reception circuit 12 from data sent from a host 3 and sent to a transmission line 1 via a tranmission circuit 11 at the acquisition of the transmission right. Further, a master node transfers the token after the execution of transmission and the destination of transfer is not the next node but a node having the largest wating number while the transmissio request waiting number of each node is compared entirely in a network constitution table 9. A slave node receiving the special token acquires the transmission right, returns the special token after the execution of transmission processing, the master node gives the token to the downstream node of the normal token transfer destination and the token is circulated in the network.

Description

[Detailed Description of the Invention] [Industrial Application Field J Data for a network system in which a plurality of transmission devices are connected to each other through a communication medium and only the device that receives a token, which is a communication rights delegation command, acquires the transmission right. This relates to transmission control methods.

[Prior Art] In recent years, local area network systems, so-called LANs, have become popular, in which a large number of communication control devices (hereinafter referred to as nodes) are connected via a transmission path, which is a communication medium, and data communication is performed between these nodes. Among the various communication methods in a LAN, the token passing method, in which only the node that receives the token, which is a command to transfer communication rights, acquires the right to transmit, provides communication services equally to all nodes even when the network is in high traffic conditions. Therefore, it is particularly excellent in that it does not cause a decrease in transmission efficiency.

Note that the token passing type network is divided into a token ring type and a token bus type depending on its physical shape. These LAN standard specifications are IEE
It has been proposed by E.Project) 802.

Here, in the token ring system, the token circulation direction is predetermined, and the delegated light of the token becomes a physically determined neighboring node.

FIG. 2 shows an example of a system configuration of a LAN using the token ring method. In the figure, reference numeral 1 indicates transmission lines 100 to 160, each of which constitutes a LAN. Each node A-G (10
0 to 160) are connected to hosts A to G (200 to 260) that process transmission information, respectively. The basic operation of token access is as follows.

(1) A node that has transmitted data monitors the circulation of the token while reproducing the received signal sequence, and when the priority of the transmitted data is equal to or greater than the priority of the token, access control within the token is performed. The T bit is rewritten to indicate that it is the beginning of a frame, and then a bit string leading to the frame status under frame control is sent out.

(2) The node at the destination address of the frame checks whether the destination address matches its own node address while reproducing and relaying the received signal sequence, and if so, copies the frame. The address is then recognized, and the frame status is set to indicate that the frame has been copied and reported to the source node.

(3) The source node erases the received frame, and after confirming that the beginning of the already transmitted frame has gone through by checking that the source address matches its own node address, it sends a token and transfers the transmission right to the next note. give it to

FIG. 3 shows the system configuration of a token bus type LAN. The nodes in the figure are the same as those in FIG. 2, so they are given the same numbers.

In this way, since a bus LAN generally shares one transmission path, a logical ring is formed and tokens are sequentially passed. For example, a logical ring similar to that shown in FIG. 2 is constructed. A token circulation diagram using this logical ring is shown in FIG. 4. In other words, each node has the preceding node that receives the token, and the downstream node that will then pass the token to the M A Cffjj control command "Who-follow" and set-t- 5uccess
You can know by sending and receiving ``o r''.You can also know whether there is a newly added node by sending and receiving MAC control commands.
5olicit-successor" and monitor the response, and if found, incorporate the node into the logical ring.

When there are multiple newly added nodes, the responses will conflict, so in order to avoid this, the MAC control command "r"
esolve-contention'' is used.

The maximum token holding time of a node that has acquired the transmission right using the token is determined in advance by the LAN system, and the node holds the transmission right within the range of the token maximum holding time, and then transfers the token to a downstream node.

[Problems to be solved by the invention j The token passing method is an excellent transmission control method as described above, but when actually using a LAN to connect devices to each node and operating it, the characteristics of this token passing method are The equal circulation of tokens and the transfer of tokens within the maximum token holding time may actually cause problems.

For example, in a system where a personal computer and a host computer coexist as devices, the host computer that serves all nodes will receive more frequent communication requests, but once the token is delegated, the token will not be sent to all other nodes until the token has circulated to all other nodes. The number of transmission requests that cannot obtain transmission rights again and is in a waiting state for transmission continues to increase.

Even if a token is obtained again in such a state, the token will be transferred to the next node due to the maximum token holding time restriction before all transmission requests are processed.

In other words, in the conventional talk passing control method, the opportunity to provide communication service to a node with a large amount of communication requests is the same as that of other nodes, and it is not possible to respond to communication requests sufficiently, and in extreme cases In some cases, the processing operation stopped.

[Means for solving the problem] In order to solve the above problem, the transmission devices that make up the network hold the amount of information waiting to be sent, and the specific transmission device of the network system The amount of information waiting to be sent is stored and updated, and when a specific transmission device acquires the communication right using a token, the communication right is granted by the token to the stored transmission device with the largest amount of information waiting to be sent. The configuration is such that the information is delegated.

[Operation] With the above configuration, a specific transmission device in the network system stores information indicating the amount of information waiting to be sent to each transmission device composing the network, and when delegating communication rights using a token, the information waiting to be sent is stored. By delegating the token to the transmission device with the largest amount of transmission, the chances of acquisition of communication rights to the device with the largest number of transmission requests are increased.

[First Embodiment] Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

[Mate Configuration (FIG. 1)] FIG. 1 is a block diagram of a node according to an embodiment of the present invention, which constitutes the network system shown in FIG. 3. The explanation of FIG. 3 is omitted because it has been described above.

In FIG. 1, 1 is a LAN network transmission path, 2 is a node which is a transmission control device, and 3 is various computer equipment and office equipment (hereinafter referred to as hosts) connected to the node 2. In FIG.

The node 2 includes a transmitting circuit 11 and a receiving circuit 12 that perform data communication with the transmission path 1, a token discrimination diagram that determines whether the received data in the receiving circuit 12 is a token, a path 4, overall control of the mate, and A control unit (hereinafter referred to as CPU) 5 that processes transmitted data, decodes and disassembles received data, and controls the timing of communication operations, a memory circuit 6 that stores transmitted and received data, control procedures for the CPU 5, etc., and a host 3. interface circuit 7, a unique address number for each mate (
an address setting unit 8 consisting of switches and the like for setting node addresses), a network configuration table 9 for storing network configuration such as address information of each constituent node of the network, number of registered transmission queues, etc., and setting maximum token holding time, etc. Timer circuit 10, destination address determination circuit 13. It consists of a transmission request waiting table 14 that updates and stores the number of transmission request frames from the host 3 stored in the memory circuit 6.

The address value set in the address setting section 8 and the 7-code information in the network configuration table 9 are read by the CPU 5 and used as the destination address, source address, etc. during transmission and reception.

Further, the transmission request waiting table 14 is a slave no.

It is always provided in the de.

Data to be transmitted from the host 3 can be sent to the transmission line 1 via the transmitting circuit 11 only when the receiving circuit 12 receives a token addressed to the own node and acquires the right to transmit.

The data to be transmitted is temporarily stored in the memory circuit 6 in the node 2, and is then formatted appropriately as communication data (
After adding the destination node address from the network configuration table 9 as the destination address value and the setting value of the address setting circuit 8 as the source address, the data is sent to the transmission path l.

To receive the transmission information, the communication data on the transmission line 1 is sent to the reception circuit 1.
2, the destination address determination circuit 13 checks the destination address value in the received data, and if it determines that it is the setting value of the address setting circuit 8 in its own node, that is, the data is addressed to its own node, it is sent to the CPU 5. This data is read into its own node, and if it is inter-node communication data such as communication control data, it is processed by the own node, and if it is data to be delivered to the host 3, some disassembly and editing processing is performed by the CPU 5. After that, it is delivered to the connected host 3.

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. When all the nodes in FIG. 3 are up, the tokens circulate as shown in FIG. 4.

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

[Network transmission frame (Figure 5)] The configuration of the transmission frame used in the network system of this embodiment is shown in Figure 5.
Shown in Figures (A), (B), and (C).

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 a token frame, and 204 is a token source node. This is transmission request special number information (hereinafter referred to as transmission queue), and the transmission queue 204 indicates the number of transmission requests currently registered as waiting for transmission in the token transmission source node.

In other words, it is the number of transmission requests for which it was not possible to process all transmission requests within the maximum token holding time, and the processing was carried over to the next token reception. 250 is a data transmission frame, 205 is a transmission code representing the data frame, 2
06 is transmission information. Further, 300 is a special token frame, and 207 is a return/request code requesting that the token be returned to the sender mate after the sending process is completed.

This embodiment receives all the token frames 200 on the transmission path 1 in the network configured as described above, and stores the transmission queue 204 in the token frames 200 in the network configuration table 9 as the transmission node information of the token frame 200. A specific node that constantly updates and writes
One node (hereinafter referred to as master node) is provided.

Therefore, the master node keeps track of the number of waiting transmission requests at the time of token acquisition for each node of all mates making up the network.

[Data Transmission Control (FIGS. 6 and 7) 1 The data transmission control of this embodiment will now be explained with reference to the flowcharts of FIGS. 6 and 7.

[Data Transmission Control of Master Node (FIG. 6) FIG. 6 is a flowchart showing data transmission control of the master node.

The data transmission control of the master node will be explained below with reference to FIG.

First, in step S1, the receiving circuit waits for receiving a transmission frame from the transmission path 1, and when the transmission frame is received, the process proceeds to step S2, where the token discrimination circuit 4 checks the transmission code area (203, 205) in the received transmission frame. Investigate,
Check whether this is the token code 203 or not. In the case of reception of a token frame, the process proceeds to step S3, where the transmission queue in the received frame is fetched, and in the subsequent step S4, the transmission queue of the node corresponding to 5A201 of the received token frame is read in the node information of the network configuration table 9. Update the imported send queue.

Then, the process proceeds to step S5, where the destination address discrimination circuit 13
compares the DA 202 in the received frame with the own node address value set in the address setting circuit 8. If the two values do not match, that is, if the transmission frame is not addressed to the node, the process returns to step S1 and prepares to receive the transmission frame addressed to the node itself.

If the transmission frame is addressed to the own node, the process proceeds to step S6, and it is checked whether the return request code 207 has been added, that is, whether or not the special token frame 300 has been received.If the special token frame 300 has not been received, the process proceeds to step S6. S
Proceed to step 7 and acquire the transmission right by receiving the token. Then, the timer circuit 10 starts counting. This timer circuit 10 is set to the maximum token holding time per node, and when the predetermined time set in the timer circuit 10 has elapsed, the token must be sent to the next node and the transmission right must be delegated.

Then, in the following step S8, it is checked whether there is data to be transmitted from the host 3 or the second node, that is, whether there is a transmission request, and if there is a transmission request, a transmission frame for transmitting the data is generated in step S9. Specifically, the food address (destination address) unique to the destination note is sent to DA20.
2, the own node address (source address) set by the address setting circuit 8 is set in 5A201, and then the transmission code 205 and transmission information 206 are set, thereby generating the data transmission frame 250. Then, in step S10, this data transmission frame 2
50 to the destination notebook according to a predetermined transmission control procedure. Since this transmission control procedure is well known, its explanation will be omitted.

Then, in the following step Sil, it is checked whether the set time of the timer circuit 10 has elapsed. When the set time has elapsed, the timer circuit 10 outputs a status signal to that effect to the CPU 5. Here, if it is within the set time, that is, within the token holding permission time, the process returns to step S8 and the next transmission data transmission process is executed.

If the set time has elapsed, the process advances to step S12, where the transmission queues of each node in the network configuration table 9 are checked, and the node with the largest transmission queue is selected. Then, in step S13, a special token frame 300 for the selected node is generated and sent, and the process returns to step S1. This special token frame 300 is generated by adding a return request code 207 representing a special token frame, and the note address selected in step 512 is set in DA 202.

In addition, if there are multiple nodes having the same transmission queue in step S12, it is sufficient to send the special token to each node in sequence. If there is no transmission request in step S8, then step S8
Proceeding to step 12, the special token frame 300 is transmitted.

On the other hand, in the case of the special token frame 300 in step S6, one transmission process for the special token frame 300 previously sent by the master node to another node (slave node) is completed, and the master node Since the token has been returned, the process proceeds to step 316, and then generates a normal token frame 200 for the downstream node to which the token should be transferred, sends it to the transmission path l via the transmission circuit 11, and transmits it. After delegating the right to the downstream node, the process returns to step S1.

If the token frame is not received in step S2, the process advances to step S20, and similarly to step SIO, the destination address determination circuit 13 determines whether the DA202 in the received frame is received.
and the own node address value set in the address setting circuit 8. If the two values do not match, that is, if the transmission frame is not addressed to the node itself, the process returns to step 31 and prepares to receive the transmission frame addressed to the node.

In the case of the transmission frame addressed to the second node, the process proceeds to step S21, in which the data transmission frame 250 addressed to the own device is received within the own node according to a predetermined transmission control procedure, and the transmission information received in step S22 is transmitted to the host node. If the information should be sent to the host 3, the process proceeds to step S23, where this information is slightly disassembled and edited, and then sent to the host 3 connected to this notebook. 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 324;
After executing the process corresponding to the received data, the process returns to step S1 and prepares for receiving the next transmission frame.

In this way, in this embodiment, if the master node has its own transmission request, it will delegate the token after executing the transmission, but the delegation light will not be transferred to the next node but to each node in the network configuration table 9. Compare all the numbers of waiting transmission requests, select the node with the largest number of waiting requests, and delegate the token to that node.

A slave node that receives this special token gains the right to transmit within the maximum token holding time, that is, one token time. After executing the transmission process, the special token is sent back to the master node. The master node that receives this special token does not transmit itself, but passes a normal token delegation light, that is, a token to the downstream node. The token then circulates around the network again.

[Data Transmission Control of Slave Node (FIG. 7)] Next, data transmission control of other nodes constituting the network, that is, slave nodes, will be explained with reference to the flowchart of FIG. 7.

In FIG. 7, the same step numbers are assigned to the same processing as in FIG. 6, and the explanation of the similar processing section will be omitted since it is redundant.

In the slave node, if a token frame is received in step S2, the process immediately proceeds to step S5, and if 5A201 is the own node address in step S5, the process proceeds to step S7 unconditionally, and the transmission process is performed in steps 57 and below. Execute.

When the transmission process is completed, the master node proceeds to step S12, but the slave node proceeds to step 314, where the transmission data stored in the memory circuit 6 that has been sent from the host 3 but has not yet been transmitted is processed. The transmission queue of the transmission request waiting table 14, which stores the number (here, the number converted to the number of transmissions in a data transmission frame), etc., is read out and expanded into the transmission request special number area 204 of the token frame to be transmitted. And then step 3
It is checked whether the received token is a special token or not in step 15, and if it is not a special token, the token frame 2 is sent in step 316.
00 and sends the token to the downstream node.

If it is a special token, proceed to step 517;
Set the DA202 of the received special token to 5A201, store the own node address set in the address setting circuit 8 in the DA202, and set the special)-Kun frame 300.
Send as. Therefore, this special token frame will be sent back to the master node.

Note that if the token frame is not received in step S2, the same processing as the master node from step 320 onwards is executed.

With the above operation, each time the token circulates once, the node with the largest number of waiting transmission requests at that time is specially given the communication right for one token time, so that the processing of transmission requests can be accelerated.

That is, a device that frequently generates transmission requests can obtain more communication services than a device connected to other nodes that generates fewer transmission requests.

[Second Embodiment] In the above explanation, the case where there is only one master node in the network has been described, but it is not necessary to limit the number of master nodes to one, and the network configuration table 9
Any node that can update the transmission queue of each node can become the master node.

Even if there are multiple master nodes in the network system, each master node only needs to execute the control flow shown in FIG. 6.

However, when the number of master nodes increases, the master node also performs the process of step 514 shown in FIG.
It is necessary to execute processing to set it in the sending token.

By controlling as described above, communication rights can be delegated using special tokens equal to the number of master nodes during one cycle of the token, and it is possible to more dynamically prevent an abnormal increase in the number of waiting transmissions, and to transfer communication rights to one master node. Even if a failure occurs, control is performed by another master node, making it possible to perform token delegation control that is resistant to failure.

In the above explanation, the special token frame 300 has a frame configuration in which the return request code 207 is added. However, the token code 203 may be used as a special token code instead of the return request code 207, and the token discrimination circuit 4 can use this special token code. It is only necessary to provide a function for determining both codes of the token code 203.

In addition, in the above explanation, if there are multiple nodes with the same transmission request queue, the master node uses the additional information of the special token frame 300 to
Specify all the applicable nodes, and send a broadcast message,
All you need to do is to control the tokens to be sent to all of the nodes.For example, the node with the smallest address among them will first acquire the transmission right and execute the transmission, and the node with the next smallest address will send the token. , after confirming that the node with the smallest address finishes sending and returns the special token to the master node, the next node acquires the right to send and starts sending. If all the nodes acquire the transmission right, the waiting time for transmission from each node will not overlap, and the master node will only have to send the special token once, and the slave nodes will also be able to send the special token to the master node. You may send it to the mate with the next smallest address without returning it.

[Third Embodiment (FIGS. 8 and 9)] In the above explanation, communication rights are delegated to a node with a large number of transmission queues using the special token frame 300 shown in FIG. 5(C), and that node Although an example has been described in which the token is returned to the special token frame transmission source node after the transmission is completed, the node receiving the token frame may be controlled to transfer this token to a normal downstream node.

At this time, the master node may alternately delegate the transmission right to a normal downstream node and delegate the transmission right to a node with a large number of transmission queues.

In this case, there is no difference in the control procedure between the slave node when receiving a special token and when receiving a normal token, and it is also possible to perform transmission control using only the token frame 200 without using the special token frame 300. .

The transmission control procedure of the master node in this case is shown in FIG. 8, and the transmission control procedure of the slave node is shown in FIG.

In both figures, the same step numbers are given to the same processing steps as in FIGS. 6 and 7, and the explanation of the steps will be omitted since they are redundant.

In the master node, in step S5, if the DA 202 of the received token frame is its own node address, that is, the address set by the address setting circuit 8, the process immediately proceeds to step S7 and acquires the transmission right.

If the transmission right exclusive time has elapsed in step Sll or if the transmission process has ended in step S8, the process proceeds to step 317. In step S17, the CPU 5 sets the "Spa flag" (not shown) in the memory circuit 6. If the "SP flag" is not set, the process of steps S12 and S13 is executed, and the token frame 200 is sent to the node with the largest number of transmission queues in the network. Then, in step 518, the "S'° flag is set and step S
Return to 1.

On the other hand, if the "S" flag is set in step 317, step 316 is executed, a token is sent to a predetermined downstream node in the network, and the "S" flag is reset in step S19.

Through the above process, the master node acquires the transmission right using the first token and sends the token to the node with the largest number of sending queues in the network, and when receiving the token for the second time, sends the token to the normal downstream node. can do.

Next, regarding the slave node, as shown in FIG.
In the process shown in the figure, it is only necessary not to perform the process on the special token frame 300, and it is sufficient to execute the process directly proceeding from step 314 to step S16.

[Fourth embodiment] In the above explanation, by delegating the special token frame,
The control was to give an extra transmission right for one token exclusive time, but in a system where there are nodes where the number of waiting requests for transmission increases abnormally, the same effect can be obtained by using a control method that gives multiple token exclusive times. For example,
For such nodes, the method is to give two tokens of exclusive time. The longer the token exclusive time given, the more the abnormal increase in waiting for transmission requests can be prevented.

In addition, even in such a system, if you want to make the communication services received by each node as equal as possible, the token exclusive time given should not be fixed.

For example, the token exclusive time to be given can be specified in the additional information of the special token.

In the case of this method, it is necessary to have a means for setting the token exclusive time to be given to the master node on the master node side.
Compare the value set in this switch setting section with the node's transmission queue, and if the node has a large number of transmission queues, set the exclusive time for 2 tokens, and if it is less than that, set the exclusive time for 1 token. It is also possible to further subdivide the settings of this switch setting section and extend the token exclusive time to three or four levels for more fine-grained control.

In this case, the token exclusive time for each 7-card can be easily set to any value by changing the setting value to the timer circuit 10.

[Effects of the Invention] As explained above, according to the present invention, it is possible to use a transmission control method that gives more communication rights to devices with a large amount of transmission requests among the transmission devices making up a network system. , the number of times communication rights are acquired can be increased in accordance with the amount of transmission requests from the transmission device, and communication rights can be allocated with good transmission efficiency.

[Brief explanation of drawings]

Figure 1 is a block diagram of a transmission device according to an embodiment of the present invention, Figure 2 is a diagram of a token ring LAN, Figure 3 is a diagram of a token bus LAN, and Figure 4 is a token circuit using a logical ring. 5(A) to 5(C) are transmission frame configuration diagrams of this embodiment. FIG. 6 is a transmission control flowchart of the master node in this embodiment. FIG. 7 is a transmission control flowchart of the slave node in this embodiment. , FIG. 8 is a master node transmission control flowchart according to another embodiment of the present invention, and FIG. 9 is a slave node transmission control flowchart according to another embodiment according to the present invention. In the figure, 1...Transmission path, 2,100-170...Node, 3...Host, 4...Token discrimination circuit, 5...
...CPU, 6...Memory circuit, 7...Interface circuit, 8...Address setting circuit, 9...Network configuration table, 10...Timer circuit, 11...
- Transmission circuit, 12... Receiving circuit, 13... Destination address discrimination circuit, 14... Transmission request waiting table, 201
... Source 7 address, 202 ... Destination address, 2
03... Token code, 204... Transmission request special number, 205... Transmission code, 207... Return request code. Patent Applicant: Canon Co., Ltd. Figure 2: Token refilling ``f3 type LAN 1'' Figure 4 Self-packing distribution 1-Token +!'l must be attached Figure 5

Claims (4)

[Claims] (1) In a data transmission control method for a network system in which a plurality of transmission devices are connected to each other through a communication medium and only the transmission device that has acquired the communication right by a token that is a communication right delegation command obtains the transmission right, the transmission device is In addition to retaining the amount of waiting information, the specific transmission device of the network system stores and updates the amount of information waiting to be sent held in each transmission device constituting the network, and the specific transmission device acquires communication rights using a token. In some cases, by delegating communication rights using a token to the transmission device that has the largest amount of information waiting to be sent, the transmission device in the network that has the largest amount of information waiting to be sent can have many opportunities to acquire communication rights. A data transmission control method characterized by giving. (2) The data transmission control system according to claim 1, wherein the specific transmission device exists only in the network system. (3) The data transmission control method according to claim 1, wherein a plurality of specific transmission devices exist in the network system. (4) When a token is transferred by a specific transmission device, the transmission device returns the token to the specific transmission device after completing the transmission process.
3. Data transmission control method according to items 3 to 3.