JPH1013413A - Network device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To locate a place of fault and improve maintainability, and to shorten a stop time if a fault occurs in a transmission line and a terminal by providing two terminals of the same constitution with three transmission lines each consisting of a going line and a return line. SOLUTION: A reception driver 11 of an A terminal 1 receives data A from a line 51 and supplies it to a reception and distribution control part 15. The control part 15 monitors whether or not the data A is abnormal, decodes an address identification code included in the data A, and supplies the data A as receive data R to a CPU 17 when the data is addressed to this terminal. When not, on the other hand, the circuit 15 outputs the data A as transmit data D to a B terminal 2. Similarly, a reception driver 13 receives data C and supplies it to the control part 15. Then when the data C is addressed to this terminal, it is supplied as data R to the CPU 17 and when the data C is addressed to another terminal, the data is supplied to a line 52 as transmit data B. Reception drivers 21 and 23 of the B terminal 2 operate similarly to supply data to the CPU 27 when it is addressed to the terminal 2 and to lines 71 and 62 as data F and C when the data is addressed to another terminal. The above-mentioned operation is repeated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network device, and more particularly to a network device including a transmission line such as a local area network (LAN), a terminal device and a relay device.

[0002]

2. Description of the Related Art Local area networks (LANs)
As is well known, a computer network for a premises that connects computers, terminals, peripheral devices, and the like installed in relatively limited places such as a premises via a high-speed transmission path. 2. Description of the Related Art Conventionally, in a network device of this type including a LAN of this type, communication network components such as a host machine, a terminal, and a modem are generally configured as a bus network or a loop network.

[0003] Recently, the number of such network devices has been increasing rapidly, and the failure thereof has a risk of causing serious damage. Therefore, when a failure occurs, it is necessary to identify and recover from the failure as soon as possible. In other words, the most important items for failure analysis when a failure occurs and the network goes down are to infer the failure location, accurately grasp the error information that each device can detect, identify this failure location, and Time is kept to a minimum.

[0004] However, it is difficult to detect a fault of this type of network device and to specify a fault location, and various methods and devices have been proposed and put to practical use.

[0005] Japanese Patent Application Laid-Open No. 63-122333 (Document 1) having a failure detection function for this type of network device.
The conventional first network device described above connects a plurality of terminals each including a diagnostic device to a transmission path of a network having a bus-type configuration, and detects a communication failure between the terminals during data transmission. It started up and specified the fault location from the difference in response time.

Referring to FIG. 4, which is a block diagram showing a relevant portion of the conventional first network device according to the present invention, the conventional first network device includes an A terminal 101 having the same configuration as a bus type transmission line 100 and an A terminal 101 having the same configuration. B terminal 201 is connected and configured.

A terminal 101 includes a transmission / reception driver 111 for transmitting / receiving data via transmission line 100,
A CPU-to-CPU communication interface 112 having an input / output function of transmitting / receiving data (communication data) to / from the U113;
A CPU 113 for executing a predetermined job corresponding to the communication data and generating a response message;
0 and a failure abnormality detection unit 114 including a diagnostic device for monitoring and detecting a failure such as a communication abnormality at the time of occurrence of the failure and specifying a failure location when the failure occurs.

[0008] The B terminal 201 includes a transmission / reception driver 211 similar to the A terminal and a CPU communication interface 21.
2, a CPU 213, and a failure abnormality detection unit 214.

Next, the operation of the conventional first network device will be described with reference to FIG. 4. First, in a normal state, a certain terminal on the transmission line 100, here A terminal 10
The first CPU 113 generates a communication message DA for the B terminal 201. CPU communication interface 112
Converts this communication message DA into transmission data Ta,
The transmission / reception driver 111 transmits the transmission data Ta to the transmission line 100 as transmission data TA. The transmission / reception driver 211 of the B terminal 201 receives the transmission data TA from the transmission line 100, generates the reception data Ra, and supplies the reception data Ra to the inter-CPU communication interface 212. The inter-CPU communication interface 212 converts the received data Ra into a communication message DA in response to the supply of the received data Ra and supplies the communication message DA to the CPU 212. CP
U212 executes a job corresponding to the communication message DA and a response message D corresponding to the communication message DA.
B is returned to terminal A101 in the reverse process.

The fault abnormality detecting units 114 and 214 constantly monitor the above communication state, and indicate that the communication is normal when the communication is normal.

Next, if there is a communication error such as a response message DB for the communication message DA from the A terminal 101 or a response message DB different from the expected content,
The fault abnormality detection unit 114 detects the abnormal state and displays the abnormal state at the same time, and activates an internal diagnostic device to specify the fault location. As described above, this diagnostic device specifies the location of the failure from the type of the response message (data) to the transmission message (data) and the return time of the response data to the transmission data.

Here, assuming that physical damage such as short-circuit of the transmission line 100 occurs and all terminals of the entire network device become unable to communicate, the same transmission line 10 is assumed.
0, a plurality of terminals are connected in parallel to perform transmission / reception at the same time, so that transmission data and response data for specifying the faulty location cannot be obtained, and thus it is impossible to specify the faulty location.

Next, a second conventional example described in JP-A-2-170640 (Reference 2) showing an example of a loop-type network device having a function of detecting a failure of the network device.
The network device includes a communication abnormality detection unit in which each terminal constituting the network detects an abnormality in received data, and transmits abnormality detection identification data from its own terminal to the next terminal. When the abnormality detection identification data is received from the previous terminal, the abnormal part is specified by relaying the previous terminal abnormality detection identification data.

Referring to FIG. 5, which is a block diagram showing a relevant portion of the second conventional network device according to the present invention, the second conventional network device includes a plurality of master stations including a master station connected on a loop type transmission line. Here, transmission lines 300 to 302 constituting the above-mentioned loop type transmission line, and A terminal 3 of the same configuration connected to these transmission lines 300 to 302
10 and a B terminal 410.

A terminal 310 includes a reception driver 311 connected to the transmission path 300 for receiving data, and a transmission driver 301.
A transmission driver 315 for transmitting data to the transmission line 301, a CPU communication interface 312 having an input / output function of transmission / reception data (communication data) to / from the CPU 313, and a predetermined job corresponding to the communication data. CPU that executes and generates a response message
313 and a communication abnormality detecting unit 31 that monitors abnormality detection identification data from a previous terminal from the transmission line 300 and detects an abnormality.
4 is provided.

The B terminal 410 includes a reception driver 411, a transmission driver 415, an inter-CPU communication interface 412, a CPU 413, and a communication abnormality detection unit 414, which are the same as those of the A terminal.

Next, with reference to FIG. 4, the operation of the second conventional network device from the first network will be described by taking the communication from the A terminal 301 to the B terminal 401 as an example. Sometimes A terminal 301
Generates a communication message DA for the B terminal 401, and the transmission driver 315 transmits the transmission data TAN obtained by adding the abnormality detection identification data N to the transmission data TA corresponding to the communication message DA to the transmission path 301. The reception driver 411 of the B terminal 410 receives the transmission data TAN from the transmission path 301, generates the reception data Ra, and
The information is supplied to the U-to-U communication interface 412 and the abnormality detection identification data N is supplied to the communication abnormality detection unit 314. The following operation is the same as that of the first conventional network device.

Next, in the B terminal 410, the A terminal 31
The transmission data TAN from 0 is interrupted or the signal T
When an abnormality such as the content of the AN is different from the normal state occurs, the communication abnormality detecting unit 414 of the B terminal 410 detects the abnormality, outputs the abnormality information, and transmits the abnormality information via the transmission driver 415 to the transmission path. 302. Thus, the abnormality detection identification data N is stored in the A terminal 301
From the B terminal 401 to the C terminal (not shown)...

The master station of the network (for example, D terminal: not shown) monitors the abnormality information of the abnormality detection identification data N transmitted in this way, and when an abnormality is detected, it determines which terminal caused the abnormality. Identify. In this case, since an abnormality has been detected in the B terminal 401, it is determined that a failure has occurred in the A terminal 301 or the transmission path 301, and the failure location is identified by analyzing the abnormality content of the abnormality detection identification data N.

However, in the conventional second network device, when communication becomes impossible due to an open transmission path or a communication driver failure of each terminal, the abnormality detection identification data cannot be relayed, and monitoring of the master station or the like is not possible. Since the supply to the terminal is cut off, it is not possible to specify the location of the failure depending on this data.

[0021]

The above-mentioned first and second conventional network devices have the same phenomenon when a failure such as a short-circuit or an open transmission line that causes the entire network device to be unable to communicate occurs. It is difficult to distinguish the failure from the failure of the communication driver or the like that causes the failure, and it is difficult to specify the location of the failure.

Further, if many terminals cannot communicate at the same time due to physical damage to the transmission path itself, transmission of fault data is also impossible, and it is also impossible to specify a fault depending on this fault data. There was a disadvantage.

Further, since a plurality of terminals commonly use the same transmission line, there is a drawback that a failure in the transmission line causes a communication failure of all terminals commonly used.

Further, when a plurality of communication drivers are connected to the same transmission line, there is a drawback that a failure of one communication driver causes a malfunction of another normal communication driver.

Further, when routing is performed using a plurality of transmission paths, if a failure occurs in one transmission path, normal routing control becomes impossible and a fault occurs in a plurality of related terminals. there were.

Further, when a failure that can destroy a device such as a lightning strike occurs in the transmission line, there is a disadvantage that a plurality of communication drivers connected to the transmission line may cause a failure.

[0027] It is an object of the present invention to improve maintainability by easily and accurately specifying a location of a failure when a failure occurs in a transmission line and a terminal, to reduce a stop time in the event of a failure, and to improve system reliability. Another object of the present invention is to provide a network device with improved operability.

[0028]

According to the present invention, there is provided a network apparatus for connecting a plurality of terminals each having a CPU and a communication apparatus via a transmission line and exchanging data with each other to execute desired processing. A first terminal, which is one of the plurality of terminals, is connected to a first transmission line forming a part of the transmission line, transmits first transmission data, and receives first reception data. A first transmission and reception driver, and a second transmission and reception driver connected to a second transmission line forming a part of the transmission line to transmit second transmission data and receive second reception data. A driver for identifying whether or not the first received data is addressed to the own terminal;
If it is not likely to transfer the data to the CPU, the data is transmitted as the second transmission data to the second transmission line via the second transmission driver, and whether or not the second reception data is addressed to the own terminal. And if it is addressed to its own terminal, the first C
A first transmission / reception distribution control unit that transmits the first transmission data to the first transmission line via the first transmission driver when the transmission is not likely to be performed to the PU;
A second terminal next to the first terminal is connected to the second transmission line, and a third terminal corresponding to the second received data is transmitted.
And a third transmission and reception driver for transmitting the third transmission data and transmitting the third reception data corresponding to the second transmission data, and a third transmission and reception driver connected to a third transmission line constituting a part of the transmission line. A fourth transmission / reception driver for transmitting the fourth transmission data and receiving the fourth reception data, and identifying whether or not the third reception data is addressed to the own terminal. If it is not likely to be transferred to the second CPU inside the own terminal, the data is transmitted as the fourth transmission data to the third transmission line via the fourth transmission driver, and the fourth reception data is transmitted to the second CPU. It is determined whether the packet is addressed to the terminal or not. If the packet is addressed to the terminal itself, and if it is not to be transferred to the second CPU, the third transmission driver sends the third transmission line to the second transmission line. Second transmission / reception transmitting as transmission data It is constituted by a signal control unit.

[0029]

FIG. 1 is a block diagram showing a first embodiment of the present invention. Referring to FIG. 1, a network device according to this embodiment shown in FIG.
Transmission line 50 comprising outgoing lines 1 and 52, outgoing line and return line 6
1 and 62, and a transmission line 70 including forward and return lines 71 and 72;
An A terminal 1 and a B terminal 2 having the same configuration and connected to 60 and 70 are provided.

The A terminal 1 is connected to a line 51 for receiving data, a transmission driver 12 connected to a line 52 for transmitting data to the line 52, and a reception driver connected to a line 62 for receiving data. A driver 13;
A transmission driver 14 connected to the line 61 for transmitting data to the line 61, determining whether or not the reception data supplied from the reception drivers 11 and 13 is addressed to the own terminal, controlling the distribution of the determination result, and transmitting the transmission data; Driver 12,1
Transmission / reception distribution control unit 15 that performs each control of distribution for 3
And transmission / reception data (communication data) for the CPU 17
Communication interface 16 having the input / output function of
And a CPU 17 for executing a predetermined job corresponding to the communication data and generating a response message.

The B terminal 2 includes reception drivers 21 and 23, transmission drivers 22 and 24, a transmission / reception distribution control unit 25, and a CPU-to-CPU communication interface 26 similar to those of the A terminal.
And a CPU 27. However, receive driver 2
The transmission drivers 22 and 24 are respectively connected to the lines 61 and 72, and the transmission drivers 22 and 24 are respectively connected to the lines 61 and 72.

Referring to FIG. 2, which is a block diagram showing an example of the configuration of the transmission / reception distribution control section 15, the reception data A and C of the reception drivers 11 and 13 corresponding to the lines 51 and 62 respectively correspond to the reception data A and C. Abnormality detection circuits 151 and 155 for detecting an abnormality of the receiver, and an identification circuit 15 for identifying whether or not the received data is addressed to the own station and outputting an identification signal ID when addressed to the own station.
2, 156, selectors 153, 157 for selecting received data as received data R to the own station CPU 17 or other station relay data in response to the supply of the signal ID, and other station relay data and transmission data T of the own station CPU 17. Selector 15 that switches between the data and outputs the data as transmission data D and B, respectively.
4,158.

Next, the operation of this embodiment will be described with reference to FIGS. 1 and 2. First, the reception driver 11 of the A terminal 1 receives the reception data A received from the line 51,
The data A is supplied to the transmission / reception distribution control unit 15. The abnormality detection circuit 151 of the transmission / reception distribution control unit 15 monitors whether or not the data A is abnormal, and outputs an enable signal EN if the data A is normal. If the data A is abnormal, the output of the enable signal EN is stopped and the alarm signal ALA is output. The identification circuit 152 decodes the destination identification code included in the data A, and outputs the identification signal ID to the selector 153 if the identification code is addressed to the own station. The selector 153 outputs the identification signal I
In response to the supply of D, data A is selected as received data R to the local CPU 117 and supplied to the inter-CPU communication interface unit 16. CPU communication interface 16
Converts the received data R into a predetermined input format and supplies it to the CPU 17.

When there is no supply of the identification signal ID, the selector 153 supplies the received data A to the selector 154. The selector 154 outputs the reception data A as transmission data D for the terminal B,
To supply. The transmission driver 14 transmits the transmission data D to the B terminal 2 via the line 61.

When transmitting the transmission data T from the CPU 17 of the own station to the terminal B or the terminal beyond it, the selector 154 is switched, the transmission data T is output as the transmission data D, and supplied to the transmission driver 14.

Similarly, the reception driver 13 receives the reception data C received from the line 62 and supplies the data C to the transmission / reception distribution control unit 15. As in the case of the reception data A, the reception data C is transmitted to the abnormality detection circuit 155 and the identification circuit 15.
6, processed by the selectors 157 and 158. When the data is addressed to the own station, the received data R is sent to the CPU 17 via the inter-CPU communication interface unit 16, and when addressed to another station, the data is sent as the transmission data B via the transmission driver 12. And supplied to the line 52.

Similarly, the reception driver 21 of the B terminal 2 receives the reception data D from the line 61 and supplies the data D to the transmission / reception distribution control unit 25. Transmission / reception distribution control unit 25
Performs the same processing as that of the transmission / reception distribution control unit 15 of the A terminal 1 on the data D, decodes the destination identification code of the data D when there is no abnormality, and receives CPU 2 via communication interface unit 26
7, when it is addressed to another station, it is supplied as transmission data F to the line 71 via the transmission driver 24.

The reception driver 23 receives the reception data E from the line 72 and supplies the data E to the transmission / reception distribution control unit 25. The transmission / reception distribution control unit 25 performs the same processing on the data E. If there is no abnormality, the destination identification code of the data E is decoded. Via CP
If it is addressed to another station, it is supplied to U27 as transmission data C to the line 71 via the transmission driver 24.

When the transmission data T is transmitted from the CPU 27 of the own station to the next terminal or the next terminal, the transmission selector in the transmission / reception distribution control unit 25 is switched, and the transmission data T is output as the transmission data F. , To the line 71 via the transmission driver 24. When transmitting the transmission data T to the A terminal 1 or the terminal in front thereof, the transmission selector in the transmission / reception distribution control unit 25 is similarly switched, and the transmission data T is output as the transmission data C. To the line 62 via

By repeating the above operation by each terminal in the network, data communication between all terminals becomes possible.

Next, referring to FIG. 3 showing a second embodiment of the present invention, the difference of the present embodiment shown in this figure from the above-described first embodiment is that the transmission path is the forward path. -The return path is not separated, that is, the transmission path 80, 81, 8 for both transmission and reception
2 and that the first terminal connected before the transmission line 82 and the transmission line 80 has a terminal 5 at each of the input and output terminals so that no loop is formed, and that the A terminal 3 substitutes for the independent driver for transmission and reception. And the transmission / reception drivers 31 and 32 connected to the transmission lines 80 and 81, respectively, and the B terminal 4 includes transmission / reception drivers 41 and 42 connected to the transmission lines 81 and 82 instead of the independent drivers for transmission and reception. .

The general operation is the same as that of the first embodiment, except that the transmission data supplied from the transmission / reception driver of the B terminal 4 to the transmission line 82 ends at the terminal 5.

[0043]

As described above, according to the network apparatus of the present invention, the transmitting and receiving drivers in which each terminal in the network is connected to an independent transmission line, and whether the received data is addressed to the own terminal or another terminal. In the former case, C
By providing the PU with transmission / reception distribution control means for relaying to the transmission driver for the transmission line for the next terminal in the latter case,
There is an effect that terminals other than the part where the failure has occurred can communicate.

Also, there is an effect that the location where a communication failure occurs can be easily specified.

Further, there is an effect that it is possible to suppress a failure occurring at one location from influencing other parts and inducing a failure.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a network device according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of a transmission / reception distribution control unit in FIG. 1;

FIG. 3 is a block diagram showing a first embodiment of the network device of the present invention.

FIG. 4 is a block diagram showing an example of a conventional first network device.

FIG. 5 is a block diagram showing an example of a second conventional network device.

[Explanation of symbols]

1,3,101,310 A terminal 2,4,201,410 B terminal 5 Termination 11,13,21,23,311,411 Receiving driver 12,14,22,24,315,415 Transmission driver 15,25 Transmission / reception Delivery control unit 16, 26, 112, 212, 312, 412 CP
U-to-U communication interface 17, 27, 113, 213, 313, 413 CP
U 31, 32, 41, 42, 111, 211 Transmission / reception driver 50, 60, 70, 80 to 82, 100, 300 to 30
2 Transmission lines 51, 52, 61, 62, 71, 72 Lines 114, 214 Failure abnormality detection units 314, 414 Communication abnormality detection units

Claims (3)

[Claims] 1. A network device that connects a plurality of terminals each including a CPU and a communication device via a transmission line and exchanges data with each other to execute a desired process, wherein the network device is one of the plurality of terminals. A first terminal is connected to a first transmission line which forms a part of the transmission line, and is connected to a first terminal.
A first transmission and reception driver for transmitting the first transmission data and receiving the first reception data, and transmitting the second transmission data by connecting to a second transmission line forming a part of the transmission line. A second transmitting and receiving driver for receiving the second received data, and identifying whether the first received data is addressed to the own terminal and, if the first received data is addressed to the own terminal, a first CPU inside the own terminal. If it is not likely to be transmitted to the terminal, the data is transmitted as the second transmission data to the second transmission line via the second transmission driver, and whether or not the second reception data is addressed to the own terminal is determined. When the identification is addressed and the terminal is not to be transferred to the first CPU, otherwise, it is transmitted to the first transmission line as the first transmission data via the first transmission driver. Transmission and reception distribution control means, Serial first second terminal is a next terminal of terminals, connected to said second transmission line and the second receiving data corresponding third
A third transmission and reception driver for transmitting the third transmission data corresponding to the second transmission data and transmitting the third transmission data, and a third transmission and reception driver connected to a third transmission line constituting a part of the transmission line. A fourth transmission / reception driver for transmitting the fourth transmission data and receiving the fourth reception data; and identifying whether the third reception data is addressed to the own terminal, If it is not likely to be transferred to the second CPU inside the own terminal, the data is transmitted as the fourth transmission data to the third transmission line via the fourth transmission driver, and the fourth reception data is transmitted to the second CPU. It is determined whether the packet is addressed to the terminal or not. If the packet is addressed to the terminal itself, and if it is not to be transferred to the second CPU, the third transmission driver sends the third transmission line to the second transmission line. Second transmission / reception transmitting as transmission data Network device, characterized in that it comprises a distribution control means. 2. The network device according to claim 1, wherein each of the first, second, and third transmission lines includes an independent transmission line for each of a forward path and a return path of communication data. . 3. The first transmission / reception distribution control means identifies whether each of the first and second received data is addressed to its own terminal, and outputs first and second identification signals, respectively. First and second identification means, respectively responsive to the supply and non-supply of each of the first and second identification signals, to each of the first and second received data with the first CPU and the first CPU. 2, a selection means for supplying one of the first transmission driver and the second transmission / reception distribution control means, wherein the second transmission / reception distribution control means is directed to each of the third and fourth received data. Third and fourth identification means for identifying whether or not the third and fourth identification signals are output, respectively; and providing the third and fourth identification signals in response to supply / non-supply of the third and fourth identification signals, respectively. Third, each of the fourth received data is transmitted between the second CPU and each of the fourth and third transmission drivers. 2. The network device according to claim 1, further comprising a selection unit that supplies one of the network devices.