JPH0528548B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention is applicable to LAN (Local Area Network)
This invention relates to communication control devices for network systems such as network systems.

[Description of prior art] As a network system such as LAN, OA
(Office Automation) or FA (Factory
A star method, a loop method, a bus connection method, or a hybrid method of these methods have been proposed for use in communication systems (Automation), but in any of these methods, data transmission between terminals is performed using a communication control device of each node.

Traditionally, a store-and-forward type communication control device has been used in the nodes of a network system, such as a star network system, and a terminal that wants to send data attaches a destination etc. to the data and transmits it to the node. The sent data is once stored in a buffer memory, and after predetermined confirmation work is performed, the data stored in this memory is transmitted to the destination terminal. In this way, a network system using a store-and-forward type communication control device has a simple communication control mode that allows each terminal to specify the terminal to which data is to be transferred and transmits the specified data, resulting in high transmission quality and high versatility. Katta.

However, in network systems that use store-and-forward type communication control devices in nodes, there is a problem in that data is exchanged after being stored in a buffer memory, which requires additional transmission time. . Particularly when there is a large amount of data to be transmitted, the data must be divided and sent as packets of a predetermined amount, and the time required to divide and generate packets is also large, making it difficult to transmit urgent data or large amounts of data. There is a problem in that it is difficult to apply a store-and-forward type communication control device to nodes of a network system that have terminals that want to communicate.

[Purpose of the invention]

The purpose of this invention is to improve the above-mentioned problems and provide a communication control device for a network system that can transmit data at higher speeds depending on the type of data while adopting the record exchange method. .

[Summary of the invention]

In order to achieve the above object, the present invention provides a store-and-forward communication control device in a network system, including a plurality of connectors connecting a plurality of terminals, an input line connecting each of the connectors to a system bus, A hard logic circuit consisting of a large number of gate switches arranged in a matrix between output lines, and a data command code analysis/judgment unit that determines whether a data transmission packet is a direct connection request packet or a direct connection cancellation packet. , and an output port that controls on/off of each of the gate switches in the hard logic circuit according to the judgment of the data command code analysis/determination section, and is configured to directly enable communication between the terminals.

[Explanation of Examples]

Hereinafter, this invention will be described in detail by way of an example.

Figure 1 is a system block diagram of a star type LAN, Figure 2 is a configuration block diagram of a communication control device,
FIG. 3 is a circuit diagram of a hard logic output port and a heart logic circuit included in the communication control device, FIG. 4 is a functional block diagram of the communication control device, and FIG. 5 is a processing flowchart of the communication control device.

As _shown in _{FIG .
T4} ) is connected. Connection is communication cable _L1 ,
They are serially connected via L ₂ , L ₃ , L ₄ , and each cable is connected to the communication control device 3 or terminal T via connectors C (C ₁ , C ₂ , C _{3 .} . . ). Although the connection complies with the RS232C standard,
Changes to the RS422 standard etc. can be made freely. Note that terminals for OA include computers, computer equipment, databases, etc. for sales, accounting, etc., and terminals for FA include CNC.
Equipment etc. are added. Also, in this example, terminals T ₁ to T ₄ are connected to four connectors C ₁ to C ₄ ,
Although connectors C ₅ and C ₆ are left vacant, any terminal can be connected to these connectors C ₅ and C ₆ .

As shown in FIG. 2, the communication control device 3 includes a CPU 9 and a ROM internally via a system bus 5.
11, RAM13, programmable timer 15,
programmable interrupt controller 17,
Six Yuarts (Universal Asyncronus)
Receiver Transmitter) U ₁ to _{U 6} and an output port 19 for hard logic. Each of the units U ₁ to _{U 6} is connected to the connectors C ₁ to _{C 6} via a hard logic circuit 21 controlled by an output port 19.

The CPU 9 performs overall control of the communication control device 3 as a whole. The ROM 11 stores the overall control program. Said RAM13
In addition to having a work area for the CPU, it also has a management table for managing the communication status of each terminal, a data command function table for analyzing the contents of commands sent from each terminal, and the like.

The programmable timer 15 performs time control during interrupt processing and the like. The programmable interrupt controller 17 interrupts packets input from each terminal.

As shown in Figure 3, the hard logic circuit 2
1 is connected to the six gate switches (no reference numbers) on the output lines l ₁ to l 6 from each uart U ₁ to _{U 6 and} to the uarts U ₁ to _{U 6} orthogonal to the output lines l ₁ to _{l 6} . are provided in a matrix between the input lines m ₁ to m ₆ of
30 gate switches (no reference numbers). Signal input terminal of each gate switch (0
-1), (0-2)...(0-6), (1-2) ~ (1
~6) When a high level signal is input to..., the gate is released.

On the other hand, the output port 19 has six IC circuits P ₁ to P ₆ , and each port P ₁ to _{P 6} receives a control signal from the CPU 9 (see FIG. 2) via the system bus 5. Predetermined signal output terminals (6-1), (5-
1) Output a high level signal from (0-6). These signal output terminals (6-1), (5-1)...
(0-6) are connected to signal input terminals of the same number on the gate switch.

In Fig. 3, signals such as data inputted from connectors _C1 to _C6 are inputted to each user _U1 to _U6 via input lines _m1 to _m6 , and are also arranged in a matrix. If any one of the gate switches is turned on, the input line and output line connected to that gate switch are directly connected. Then, by activating the output port 19, the CPU 9 connects the output circuit line l ₁
Turn on the gate switch on ~l ₆ as appropriate and send the information sent from the - terminal to yourart U ₁ ~ _{U 6}
By activating the output port 19, appropriate input lines m ₁ to _{m 6} can be directly connected to appropriate output lines l ₁ to _{l 6} . It means that you can.

In order to directly connect and disconnect the input lines _m1 to _m6 and the output lines _l1 to _l6 , the communication control unit 2
3 is provided. This communication control unit 23 is a functional expression of the part related to communication control of the communication control device 3.If the function is shown in a block diagram, as shown in FIG. unit 25 and data transmission/reception buffer memory 2
7, a data error check processing section 29, a data command code analysis and determination section 31, a data command code function table 33, a destination address determination processing section 35, and a transmission data output processing section 37. The transmission method is a packet method,
The packet PKT shown in the center right of FIG. 5 has a header at the beginning indicating the start of data transmission, and then
It has a destination address, a source address, a command code, transmission data, a data check code, and finally a trailer indicating the end of the data. The command code is a designation of the processing mode in the communication control device, and in this example, a command for requesting direct line connection can be written in particular.

In FIG. 4, the reception interrupt processing section 25
accepts packets from each terminal using an interrupt method. The data transmission/reception buffer memory 27 temporarily stores transmission data in interrupt-processed packets. The data error check processing section 29 reads the data check code in the packet and checks whether the number of transferred bytes, parity check, etc. are appropriate. The data command code analysis and determination section 31 reads command codes.

The data command function table 33 is provided with a management table for managing the communication status of each terminal, and also records information for analysis of required command codes. The destination address determination processing section 35 reads the destination address of the packet. The transmission data output processing section 3
7 is the data command code function table 3
In accordance with the command code analyzed and determined in accordance with FIG. To control the gate switch shown in , or if the command code is a direct command, regardless of the data transmission/reception buffer memory,
The matrix-shaped gate switches shown in FIG. 3 are controlled to directly connect the destination terminal and the destination terminal requested by the source terminal. If a request is made to cancel the direct connection from a terminal that is already directly connected, the transmission data output processing unit 37 performs the process to cancel the direct connection _. This is done on the condition that a packet is sent via _U6 to request the release of the direct connection.

The control method of the communication control device having the above configuration will be explained using the flowchart of FIG.

Referring to FIG. 3, the signals input from the connectors _C1 to _C6 to the input lines _m1 to _m6 are generally input in the form of packets. Only when turned on and directly connected to a specific circuit, that specific line can flow other types of signals. In this example, the contents of the packet can be roughly divided into three types. As shown in the upper right corner of FIG. 5, these are packet A for normal data transmission, packet B for requesting direct connection, and packet C for canceling direct connection.

As shown in the explanation section of Fig. 4, packet A is
A destination address, a source address, transmission data, a data check code, and a command code are inserted between the head and the trailer. In packet B, a direct connection request is written in the command code, the transmission data section is left blank, and the transmission destination code is communication control device 3 (see FIG. 1).
Packet C, unlike packet B, has direct connection release written in the command code. In this example, the reason why packets B and C are defined in the same format as packet A is that the direct connection request,
Direct connection release signal without special installation of hard wire etc.
Further, it is a means for processing without complicating the processing technology of a communication control device that requires packet transmission.

Step 501 is for accepting interrupt processing for packets A to C, and if there is an interrupt, packet reception processing is performed in step 503. step
Step 505 performs a data error check process, and step 507 performs a command code analysis process (see FIG. 4).

The main command analysis process in step 507 is to determine whether the packet content is A, B, or C. Step 509 determines whether or not to release the direct connection.
That is, it is determined whether it is packet C or not. In addition, step 511 determines whether or not there is a direct connection, that is,
It is determined whether the packet is packet B or not. Therefore, if the packet input to the communication control device is packet A, the process advances to step 513. Packet B
If so, the process moves to step 523.

In step 513, since packet A is a packet for data transmission, the management table in the data command code function table shown in FIG. Determine. At this time, if the destination terminal is communicating with another terminal or is otherwise unable to communicate,
In step 517, processing to disable transmission is performed. The process of disabling transmission is, for example, by notifying the sending terminal of the fact, or by displaying a message to that effect on an appropriate display device, if necessary.

If it is determined in step 515 that transmission is possible, the process moves to step 519, where predetermined transmission processing is performed. The transmission process is performed by transferring the data in the received packet temporarily stored in the data reception buffer memory shown in FIG. 4 to a predetermined destination terminal. Step 521 is for table change processing, and a desired command such as that the terminal is currently transmitting or that communication should be disabled for a predetermined period of time with a predetermined terminal due to the content of the transmission is sent as shown in FIG. The entries in the data command function table shown are performed.

If direct connection, that is, packet B is determined in step 511, the same management table as in step 513 is referenced in step 523. step
If 525 determines that direct connection is not possible, the step
At step 527, a direct connection disabling process, that is, a process similar to step 517, is performed, but if it is determined at step 525 that a direct connection is possible, the process moves to step 529, where the following direct connection process is performed.

As shown in FIG. 3, when the CPU 9 determines direct connection processing, it outputs a high level signal to a predetermined output terminal of the output port 19. That is, for example,
Now, if terminal 4 (for example, a personal computer in the data usage department) is making a direct connection request to terminal 3 (for example, a data bank), then CPU 9
outputs a high level signal to the terminal (4-3) of port _P3 , and turns on the gate switch having the input terminal (4-3) via the line shown by the broken line. Input line m ₄ is connected to output line l ₃ to connector C ₃ , thereby directly connecting line m ₄ and line l ₃ .

In step 531, after the line is directly connected, that fact is recorded in the management table included in the data command code function table shown in FIG. By the way, the lines _m4 and _l3 are directly connected, but at this time the input line
It is as if the signal from _m4 is mixed into the system bus via _U4 , but in reality, such mixing can be avoided by using handshake control signal lines such as CTS and RTS of the RSC standard. It will be done.

Next, in step 509, the direct connection is canceled, that is, the packet C
If it is determined, the process moves to step 533. Packet C
is input from connector _C4 shown in FIG. 3 in the example below step 523. Step 533 indicates a process for canceling direct connection, which is performed by setting the signal level of the output terminal (4-3) of port _P3 shown in FIG. 3 to a low level. Step 535 shows the process of changing the management table, and it is written in the management table that the direct connection has been released.

As a result of the above, each terminal can perform packet communication with other terminals using the conventional store-and-forward method, and can also perform direct connection communication accordingly.

It should be noted that the direct connection request can be made by automatically determining the speed by considering the predicted transmission time in advance, or it is of course possible to make it manually with operator intervention. It is.

〔Effect of the invention〕

As can be understood from the above description of the embodiments, the present invention is, in short, a store-and-forward type communication control device in a network system, which includes a plurality of connectors C1 to C4 that connect a plurality of terminals T1 to T4; Input lines and output lines l ₁ to connect each of the above connectors C1 to C4 and the system bus 5
l ₆ : Hard logic circuit 2 consisting of a large number of gate switches arranged in a matrix between m ₁ and m ₆
1, and a data commad code analysis/judgment unit 3 that determines whether the data transmission packet PKT is a direct connection request packet B or a direct connection release packet C.
1, and the data command code analysis/judgment section 31
and an output port 19 for controlling on/off of each of the gate switches in the hard logic circuit 21 according to the determination of each terminal T.
This configuration allows direct communication between T1 and T4.

With the above configuration, in the present invention, when a direct connection request packet B requesting connection with another terminal is transmitted from a certain terminal, the command of the packet B is analyzed in the data command code analysis/determination section 31, and this determination section 31 According to the determination, the corresponding gate switch in the hard logic circuit 21 is turned on, and the terminal is directly connected to the other terminal and becomes capable of direct communication.

In other words, in the present invention, since each terminal can communicate with each other while being directly connected, it is effective in shortening the time required to transfer large-capacity file data when directly connected, and it is also possible to exchange data regardless of data block format. Therefore, data transmission efficiency is further improved.

[Brief explanation of the drawing]

Each of the drawings shows an embodiment of the present invention; Fig. 1 is a system block diagram of a star network system, Fig. 2 is a block diagram of the configuration of a communication control device, and Fig. 3 is a block diagram of a configuration of a communication control device. FIG. 4 is a circuit diagram of the hard logic circuit, FIG. 4 is a functional block diagram of the communication control device, and FIG. 5 is a control flowchart of the communication control device. 1...Star network system, 3
...Communication control device, 19...Output port, 21...
…hard logic circuit, C ₁ to C ₆ … connector,
T ₁ ~ _{T 4} ... terminal, U ₁ ~ _{U 6} ... your art.

Claims (1)

[Claims] 1 A store-and-forward communication control device in a network system that supports multiple terminals (T1
~T4) are connected to multiple connectors (C1~C
4), and input lines and output lines ( _l1 to _l6 :
A hard logic circuit 21 consisting of a large number of gate switches arranged in a matrix between (m ₁ to m ₆ )
, a data command code analysis and determination section 31 that determines whether the data transmission packet (PKT) is a direct connection request packet B or a direct connection release packet C; and the data command code analysis and determination section 3.
1, and an output port 19 that controls on/off of each gate switch in the hard logic circuit 21 according to the determination in step 1, and has a configuration that allows direct communication between the terminals (T1 to T4). A communication control device for a network system.