阅读说明：本技术 网络检查系统及网络检查程序 (Network inspection system and network inspection program ) 是由 大森康宏 跡部悠太 冈南佑纪 于 2019-03-05 设计创作，主要内容包括：检查控制部(210)确认连接有1个以上的节点的通信网络(101、102)的通信状况,基于所述通信状况判定能否检查所述通信网络。在判定为能够检查所述通信网络的情况下,检查控制部向所述通信网络输出基础信号,该基础信号是用于检查所述通信网络的脉冲信号。检查部(220)受理通过在所述通信网络中流动而改变了波形的基础信号即检查信号,基于所述检查信号的波形,判定有无与所述通信网络连接的新的节点。(An inspection control unit (210) confirms the communication status of a communication network (101, 102) to which 1 or more nodes are connected, and determines whether or not the communication network can be inspected based on the communication status. When it is determined that the communication network can be checked, the check control unit outputs a base signal, which is a pulse signal for checking the communication network, to the communication network. An inspection unit (220) receives an inspection signal that is a base signal whose waveform has been changed by flowing through the communication network, and determines the presence or absence of a new node connected to the communication network based on the waveform of the inspection signal.)

1. A network inspection system in which, in a network inspection system,

the network inspection system includes:

a communication status confirmation unit configured to confirm a communication status of a communication network to which 1 or more nodes are connected, and determine whether or not the communication network can be checked based on the communication status;

a basic signal output unit that outputs a basic signal, which is a pulse signal for checking the communication network, to the communication network when it is determined that the communication network can be checked; and

and a node determination unit that receives an inspection signal that is a base signal whose waveform has been changed by flowing through the communication network, and determines whether or not a new node connected to the communication network is present based on the waveform of the inspection signal.

2. The network inspection system of claim 1,

the network inspection system is provided with a conversion circuit that converts an analog signal into digital data,

the base signal output section shifts phases and outputs a plurality of base signals to the communication network,

the conversion circuit obtains 1 or more sampling values for each of the plurality of inspection signals corresponding to the plurality of base signals by sampling each of the plurality of inspection signals,

the node determination unit receives 1 or more sampling values of each of the plurality of inspection signals, restores the waveform of the inspection signal using the 1 or more sampling values of each of the plurality of inspection signals, and performs determination based on the restored waveform.

3. The network inspection system of claim 2,

the network inspection system is provided with a phase shift circuit that shifts the phase of a pulse signal,

the base signal output section indicates the phase shift of the base signal to the phase shift circuit,

the communication status confirmation unit confirms the communication status of the communication network using a time until the phase shift in the phase shift circuit is stabilized after the instruction to the phase shift circuit.

4. The network inspection system of any one of claims 1 to 3,

the network inspection system includes a communication management unit that instructs each node connected to the communication network to stop communication when it is determined that the communication network cannot be inspected.

5. The network inspection system of any one of claims 1 to 3,

the communication status confirmation unit determines whether or not communication has occurred in the communication network during an observation time from when a base signal is output to the communication network to when an inspection signal is received,

the basic signal output unit outputs a basic signal to the communication network again when communication occurs in the communication network during the observation time.

6. The network inspection system of claim 5,

the network inspection system includes a communication management unit that instructs each node connected to the communication network to perform retransmission when communication occurs in the communication network during the observation time.

7. The network inspection system of any one of claims 1 to 6,

the network inspection system includes a switching unit that sequentially switches a communication network to be an output destination of a basic signal with respect to a plurality of communication networks and switches a communication network to be an input source of an inspection signal to the output destination.

8. A network check program, wherein,

the network check program is for causing a computer to execute:

a communication status confirmation process of confirming a communication status of a communication network to which 1 or more nodes are connected, and determining whether or not the communication network can be checked based on the communication status;

a basic signal output process of outputting a basic signal, which is a pulse signal for checking the communication network, to the communication network when it is determined that the communication network can be checked; and

and a node determination process of receiving an inspection signal that is a base signal whose waveform has been changed by flowing through the communication network, and determining whether or not a new node connected to the communication network is present based on the waveform of the inspection signal.

Technical Field

The present invention relates to the detection of illegitimate nodes connected to a communication network.

Background

When an unauthorized node is connected to a communication network such as an in-vehicle network, normal processing may not be performed in the communication network.

Therefore, it is important to detect an illegal node connected to the communication network.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-031718

Disclosure of Invention

Problems to be solved by the invention

As a technique for detecting a fault at a node disposed on a transmission line, a technique called TDR is known. In the TDR, a fault of a node is detected based on a change in the waveform of a pulse signal flowing through a power transmission line. TDR is short for Time Domain refilectmetric.

Patent document 1 discloses a technique related to TDR. Specifically, a method of specifying a location of occurrence of an accident based on a reflection time of a pulse wave output to a power transmission line is disclosed.

However, TDR is a technology for a power line, and cannot be directly applied to a communication network. For example, when the TDR is directly applied to the communication network, the communication in the communication network may be affected by the TDR and the communication may not be performed normally.

It is an object of the present invention to enable detection of an illegal node without affecting the communication in a communication network.

Means for solving the problems

The network inspection system of the present invention includes: a communication status confirmation unit configured to confirm a communication status of a communication network to which 1 or more nodes are connected, and determine whether or not the communication network can be checked based on the communication status; a basic signal output unit that outputs a basic signal, which is a pulse signal for checking the communication network, to the communication network when it is determined that the communication network can be checked; and a node determination unit that receives an inspection signal that is a base signal whose waveform has been changed by flowing through the communication network, and determines whether or not a new node connected to the communication network is present based on the waveform of the inspection signal.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, an illegal node (new node) can be detected without affecting communication in a communication network.

Drawings

Fig. 1 is a block diagram of a network inspection system 100 according to embodiment 1.

Fig. 2 is a block diagram of the network inspection apparatus 200 according to embodiment 1.

Fig. 3 is a flowchart of the network inspection method in embodiment 1.

Fig. 4 is a relationship diagram of various signals in embodiment 1.

Fig. 5 is an explanatory diagram of confirmation of a communication status in embodiment 1.

Fig. 6 is an explanatory diagram of confirmation of a communication status in embodiment 1.

Fig. 7 is a configuration diagram of the network inspection system 100 according to embodiment 2.

Fig. 8 is a configuration diagram of the network inspection apparatus 200 according to embodiment 2.

Fig. 9 is a flowchart of a network inspection method in embodiment 2.

Fig. 10 is a flowchart of a network inspection method in embodiment 2.

Fig. 11 is an explanatory diagram of recovery of the inspection signal 112 in embodiment 2.

Fig. 12 is a configuration diagram of the network inspection system 100 according to embodiment 3.

Fig. 13 is a configuration diagram of the network inspection apparatus 200 according to embodiment 3.

Fig. 14 is a flowchart of a network inspection method according to embodiment 3.

Fig. 15 is a configuration diagram of the network inspection system 100 according to embodiment 4.

Fig. 16 is a configuration diagram of the network inspection apparatus 200 according to embodiment 4.

Fig. 17 is a flowchart of a network inspection method according to embodiment 4.

Fig. 18 is a flowchart of a network inspection method according to embodiment 4.

Fig. 19 is an explanatory diagram of retransmission of a communication signal in embodiment 4.

Fig. 20 is a hardware configuration diagram of the network inspection device 200 according to the embodiment.

Detailed Description

In the embodiments and the drawings, the same elements or corresponding elements are denoted by the same reference numerals. The description of the elements denoted by the same reference numerals as those of the already described elements is appropriately omitted or simplified. The arrows in the figure primarily indicate the flow of data or processing.

Embodiment 1.

A manner for detecting an illegal node connected to a communication network is explained based on fig. 1 to 6.

Description of the structure of Tuliuzhang

The structure of the network inspection system 100 is explained based on fig. 1.

The network inspection system 100 has 1 or more communication networks.

Specifically, the network inspection system 100 has a 1 st network 101 and a 2 nd network 102.

However, the network check system 100 may have 1 communication network, and may have 3 or more communication networks.

For example, the communication network is an in-vehicle network. The specific vehicle-mounted Network is a Controller Area Network (CAN).

Each communication network is connected with 1 or more nodes. For example, the node is an in-vehicle device.

The "normal node" is a node connected to the 1 st network 101 and is legally connected to the 1 st network 101.

The "illegal node" is a node newly connected to the 1 st network 101, and is illegally connected to the 1 st network 101.

The network inspection system 100 includes a network inspection device 200 for detecting an unauthorized node.

The configuration of the network inspection apparatus 200 will be described with reference to fig. 2.

The network inspection apparatus 200 is a computer including hardware such as a processor 201, a memory 202, an auxiliary storage device 203, an input/output interface 204, a communication interface 205, and various circuits. These pieces of hardware are connected to each other via signal lines.

Specifically, the network inspection device 200 is provided with circuits such as a pulse signal circuit 281, a 1 st selector 282, a 2 nd selector 283, and an AD conversion circuit 284.

The processor 201 is an IC that performs arithmetic processing, and controls other hardware. The processor 201 is, for example, a CPU or a DSP.

IC is an abbreviation for Integrated Circuit.

The CPU is an abbreviation for Central Processing Unit (CPU).

The DSP is a short for Digital Signal Processor.

The memory 202 is a volatile storage device. The memory 202 is also referred to as a main storage device or main memory. For example, the memory 202 is a RAM. The data stored in the memory 202 is stored in the auxiliary storage device 203 as needed.

RAM is a short for Random Access Memory (RAM).

The auxiliary storage device 203 is a nonvolatile storage device. The secondary storage device 203 is, for example, a ROM, HDD, or flash memory. Data stored by the secondary storage device 203 is loaded to the memory 202 as needed.

ROM is an abbreviation for Read Only Memory (ROM).

The HDD is an abbreviation for Hard Disk Drive.

The input/output interface 204 is a port to which an input device and an output device are connected. For example, the input/output interface 204 is a USB terminal, the input device is a keyboard or a mouse, and the output device is a display.

USB is a short for Universal Serial Bus (Universal Serial Bus).

The communication interface 205 is an interface for communication. For example, the communication interface 205 is a communication port. The input/output of signals between the network inspection apparatus 200 and each communication network is realized using the communication interface 205.

The pulse signal circuit 281 is a circuit that generates a pulse signal.

The 1 st selector 282 and the 2 nd selector 283 are circuits for switching to a communication network to be connected, respectively.

The AD conversion circuit 284 converts an analog signal into digital data. The AD conversion circuit is also referred to as an AD converter.

The network inspection device 200 includes elements such as an inspection control unit 210 and an inspection unit 220. These elements are implemented in software.

The inspection control unit 210 includes a communication status confirmation unit 211, a base signal output unit 212, and a switching unit 213.

The inspection unit 220 includes a node determination unit 221 and a result output unit 222.

The auxiliary storage device 203 stores a network inspection program for causing a computer to function as the inspection control unit 210 and the inspection unit 220. The network check program is loaded into the memory 202 and executed by the processor 201.

The OS is also stored in the auxiliary storage device 203. At least a portion of the OS is loaded into memory 202 for execution by processor 201.

The processor 201 executes the network check program while executing the OS.

OS is an abbreviation for Operating System.

The input/output data of the network inspection program is stored in the storage unit 290.

The memory 202 functions as the storage unit 290. However, a storage device such as the auxiliary storage device 203, a register in the processor 201, and a cache memory in the processor 201 may function as the storage unit 290 instead of the memory 202 or together with the memory 202.

The network inspection apparatus 200 may include a plurality of processors instead of the processor 201. The plurality of processors share the role of the processor 201.

The network check program can be recorded (stored) in a non-volatile recording medium such as an optical disc or a flash memory in a computer-readable manner.

Description of the actions of Tuzhang

The operation of the network inspection apparatus 200 corresponds to a network inspection method. The steps of the network inspection method correspond to the steps of the network inspection program.

The network checking method is explained based on fig. 3.

In step S101, the communication status confirmation unit 211 selects 1 unselected communication network.

The communication network selected in step S101 is referred to as a "selected network".

In step S102, the switching unit 213 switches the communication network to which the base signal is output to the selected network. The basic signal is described later.

Specifically, the switching unit 213 inputs a 1 st selector signal designating the selected network to the 1 st selector 282. The 1 st selector signal is a signal for controlling the 1 st selector 282.

Then, the 1 st selector 282 switches the connection destination to the selected network in accordance with the 1 st selector signal.

The switching unit 213 switches the communication network that is the input source of the inspection signal to the selected network. The check signal is described later.

Specifically, the switching unit 213 inputs a 2 nd selector signal specifying the selected network to the 2 nd selector 283. The 2 nd selector signal is a signal for controlling the 2 nd selector 283.

Then, the 2 nd selector 283 switches the connection destination to the selected network in accordance with the 2 nd selector signal.

In step S111, the communication status confirmation unit 211 confirms the communication status of the selected network.

In step S112, the communication status confirmation unit 211 determines whether or not the selected network can be checked based on the communication status of the selected network.

If it is determined that the selected network can be checked, the process proceeds to step S121.

If it is determined that the selected network cannot be checked, the process proceeds to step S111.

Confirmation of the communication condition will be described later.

In step S121, the basic signal output unit 212 outputs a basic signal to the selected network.

The base signal is a pulse signal for checking the selected network, and has a predetermined time interval. Specifically, the basic signal is a step wave.

Specifically, the base signal output unit 212 inputs a signal output command to the pulse signal circuit 281. The signal output instruction is a signal for instructing output of a pulse signal as a base signal.

Then, the pulse signal circuit 281 outputs a pulse signal having a predetermined time interval. The pulse signal output from the pulse signal circuit 281 is a base signal.

The base signal output from the pulse signal circuit 281 is input to the selection network through the 1 st selector 282.

In step S131, the node determination unit 221 receives the inspection signal flowing through the selected network.

The inspection signal is a basic signal of which waveform is changed by flowing in the selection network.

The node determination unit 221 receives the inspection signal as follows.

The inspection signal flowing in the selected network is input to the AD conversion circuit 284 through the 2 nd selector 283.

The AD conversion circuit 284 converts the input inspection signal from an analog signal to digital data, and outputs the digital data of the inspection signal. The digital data of the inspection signal is input from the AD conversion circuit 284 to the node determination unit 221.

The node determination unit 221 receives the input digital data of the inspection signal.

In step S132, the node determination unit 221 determines whether or not there is a new node connected to the selected network based on the waveform of the check signal.

The node determination unit 221 performs the determination as follows.

The inspection control section 210 notifies the inspection section 220 of the selection of the network. For example, the switching unit 213 notifies the node determination unit 221 of the selected network in step S102.

The node determination unit 221 compares the waveform of the inspection signal indicated by the digital data with the waveform of the reference signal for selecting a network, and performs determination based on the comparison result.

The relationship between the base signal 111, the inspection signal 112, and the reference signal 113 will be described with reference to fig. 4.

The base signal 111 is a pulse signal having a predetermined time interval.

The inspection signal 112 is a basic signal of which waveform is changed by flowing in the selection network. The waveform of the check signal 112 includes reflections generated by a node group (including an illegal node) connected to the selected network. In fig. 4, the waveform of the inspection signal 112 contains 4 reflections generated by 4 nodes.

The reference signal 113 is a check signal corresponding to a selected network to which only the normal node group is connected. The waveform of the reference signal 113 includes a reflection generated by a normal node group connected to the selected network. In fig. 4, the waveform of the reference signal 113 contains 3 reflections generated by 3 normal nodes.

The node determination unit 221 analyzes the impedance of the waveform of each of the inspection signal 112 and the reference signal 113. Then, the node determination unit 221 compares the number of reflections included in the waveform of the inspection signal 112 with the number of reflections included in the waveform of the reference signal 113.

When the number of reflections included in the waveform of the inspection signal 112 is larger than the number of reflections included in the waveform of the reference signal 113, the node determination unit 221 determines that a new node (illegal node) connected to the selected network exists.

When the number of reflections included in the waveform of the inspection signal 112 is equal to the number of reflections included in the waveform of the reference signal 113, the node determination unit 221 determines that there is no new node (illegal node) connected to the selected network.

When the number of reflections included in the waveform of the inspection signal 112 is smaller than the number of reflections included in the waveform of the reference signal 113, the node determination unit 221 determines that the normal node group connected to the selected network has changed.

In fig. 4, 4 reflections from 4 nodes are included in the waveform of the inspection signal 112. On the other hand, the waveform of the reference signal 113 includes 3 reflections generated by 3 normal nodes.

Therefore, the node determination unit 221 determines that a new node (unauthorized node) connected to the selected network exists.

Returning to fig. 3, the description is continued from step S133.

In step S133, the result output unit 222 outputs the inspection result of the selected network. That is, the result output unit 222 outputs a check result indicating the presence or absence of a new node connected to the selected network.

For example, the result output unit 222 displays the inspection result of the selected network on the display.

In step S141, the communication status confirmation unit 211 determines whether or not an unselected communication network exists.

In the case where there is an unselected communication network, the process advances to step S101.

In the case where there is no unselected communication network, the process ends.

The confirmation of the communication status (S111 and step S112) will be described with reference to fig. 5 and 6.

The communication status confirmation unit 211 confirms the communication status of the selected network during the confirmation time. The confirmation time is a predetermined duration.

Specifically, the communication status confirmation unit 211 confirms whether or not communication is performed, a time interval of communication, a voltage pattern of communication, and the like as the communication status.

In fig. 5 (1), the communication status confirmation unit 211 confirms the presence or absence of communication in the selected network during the confirmation time.

When communication does not occur in the selected network during the confirmation time, the communication status confirmation unit 211 determines that the selected network can be checked.

In fig. 5 (2), the communication status confirmation unit 211 confirms the time interval (communication interval) of communication in the selected network during the confirmation time.

When the communication interval in the confirmation time is longer than the predetermined interval, the communication status confirmation unit 211 determines that the selected network can be checked.

The predetermined interval is a time sufficient for network inspection and is determined in advance.

In fig. 5 (3), the communication status confirmation unit 211 confirms the time interval (communication interval) of communication in the selected network during the confirmation time.

When the communication interval in the confirmation time is shorter than the predetermined interval, the communication status confirmation unit 211 determines that the selected network cannot be checked.

In fig. 6 (4), when communication of a predetermined voltage pattern (predetermined pattern) occurs, a communication interval equal to or longer than a predetermined interval is secured until the next communication. The specification is set in advance in each node.

The communication status confirmation section 211 confirms the voltage pattern of communication in the selected network during the confirmation time.

When communication of the predetermined pattern occurs during the confirmation time, the communication status confirmation unit 211 determines that the selected network can be checked at the time point when communication of the predetermined pattern is detected.

In fig. 6 (5), when communication occurs, a communication interval equal to or greater than a predetermined interval is secured until the next communication. The specification is set in advance in each node.

The communication status confirmation section 211 confirms the voltage pattern of communication in the selected network during the confirmation time.

When the communication signal has dropped during the confirmation time, the communication status confirmation unit 211 determines that the selected network can be checked at the time when the end of the communication signal is detected.

Effects of embodiment 1

The network inspection device 200 observes the communication state of the communication network and detects a state in which TDR can be implemented. Thus, an illegal node can be detected without affecting communication.

The inspection control unit 210 switches the communication network of the connection destination by controlling the 1 st selector 282 and the 2 nd selector 283. Thus, it is possible to inspect a plurality of communication networks without providing a plurality of pulse signal circuits 281, AD conversion circuits 284, and inspection units 220.

That is, TDR can be implemented with a small number of components for a plurality of communication networks. Therefore, cost reduction and space saving of the network inspection apparatus 200 are achieved. Also, the network inspection apparatus 200 can be implemented by an embedded device. For example, the network inspection device 200 can be realized as a function of the ECU. The ECU is an abbreviation of Electronic Control Unit (Electronic Control Unit).

Embodiment 2.

The embodiment using the low-precision AD converter will be mainly described with reference to fig. 7 to 11 as to the differences from embodiment 1.

Description of the structure of Tuliuzhang

The configuration of the network inspection system 100 will be described with reference to fig. 7.

The configuration of the network inspection system 100 is the same as that in embodiment 1 except for a part of the network inspection apparatus 200 (see fig. 1).

The configuration of the network inspection apparatus 200 will be described with reference to fig. 8.

The network inspection device 200 includes an AD conversion circuit 285 instead of the AD conversion circuit 284.

The AD conversion circuit 284 is a high-precision AD converter and has a short sampling interval.

The AD conversion circuit 285 is a low-precision AD converter and has a long sampling interval.

For example, the sampling interval of the AD conversion circuit 284 is 1 nanosecond, and the sampling interval of the AD conversion circuit 285 is 10 nanoseconds.

The network inspection device 200 is further provided with a phase shift circuit 286.

The phase shift circuit 286 is a circuit that shifts the phase of the base signal output from the pulse signal circuit 281.

The other structure is the same as that in embodiment 1 (see fig. 2).

Description of the actions of Tuzhang

The network check method will be described with reference to fig. 9 and 10.

In step S201, the base signal output unit 212 inputs a phase shift command to the phase shift circuit 286. The phase shift instruction is an instruction for shifting the phase of the base signal by a predetermined amount.

The phase shift circuit 286 receives the phase shift command and then performs circuit setting (phase setting) for phase shift. After the phase setting, it takes a certain amount of time until the operation of the phase shift circuit 286 is stabilized.

In step S211, the communication status confirmation unit 211 selects 1 unselected communication network. The switching unit 213 switches the connection destination to the selected network.

Step S211 is the same as the processing in embodiment 1 (step S101 and step S102).

In step S221, the communication status confirmation unit 211 determines whether or not the selected network can be checked.

Step S221 is the same as the processing in embodiment 1 (step S111 and step S112).

In the case where the communication network can be checked, the process proceeds to step S222.

In the case where the communication network cannot be checked, the process advances to step S221.

In step S222, the base signal output unit 212 determines whether or not the phase shift is stable.

Specifically, the base signal output unit 212 compares the elapsed time after step S201 with a predetermined time.

The elapsed time after step S201 is the time elapsed from the input of the phase shift instruction to the phase shift circuit 286.

The predetermined time is a time required until the operation of the phase shift circuit 286 is stabilized after the phase setting, and is predetermined.

When the elapsed time after step S201 exceeds the predetermined time, the base signal output unit 212 determines that the phase shift has been stabilized.

If it is determined that the phase shift has stabilized, the process proceeds to step S231.

If it is determined that the phase shift is not stable, the process proceeds to step S221.

In step S231, the base signal output unit 212 outputs a base signal to the selected network.

Step S231 is the same as step S121 in embodiment 1. However, the phase of the base signal output to the selection network is shifted by the phase shift circuit 286.

That is, the base signal output unit 212 outputs the phase-shifted base signal to the selection network.

In step S232, the node determination unit 221 receives the digital data of the inspection signal flowing through the selected network.

Step S232 is a process of replacing the AD conversion circuit 284 with the AD conversion circuit 285 in step S131 in embodiment 1.

The digital data of the check signal represents more than 1 sample value of the check signal.

In step S241, the communication status confirmation unit 211 determines whether or not an unselected communication network exists.

In the case where there is an unselected communication network, the process advances to step S211.

In the case where there is no unselected communication network, the process proceeds to step S251.

In step S251, the base signal output unit 212 determines whether or not a predetermined number of phase shifts are completed. The predetermined number is a number of 2 or more, and is predetermined as the number of times of phase shift.

When the predetermined number of phase shifts is completed, the process proceeds to step S261.

If the predetermined number of phase shifts is not completed, the process proceeds to step S201.

In the repetition of the processing of steps S201 to S251, the fundamental signal output unit 212 outputs a plurality of fundamental signals to the respective communication networks while shifting the phase.

In step S261, the node determination unit 221 restores the waveform of the check signal using a predetermined number of pieces of digital data for each communication network.

Specifically, the node determination unit 221 restores the waveform of the inspection signal by arranging 1 or more sampling values indicated by each digital data in phase order.

In step S262, the node determination unit 221 determines the presence or absence of a new node for each communication network based on the waveform of the check signal.

The method of determining the presence or absence of a new node is the same as the method in step S132 of embodiment 1.

In step S263, the result output unit 222 outputs the inspection result for each communication network. That is, the result output unit 222 outputs a check result indicating the presence or absence of a new node for each communication network.

The recovery of the check signal 112 will be described based on fig. 11.

The high-precision digital data is digital data obtained by the AD conversion circuit 284. The sampling interval of the AD conversion circuit 284 is 1 nanosecond. Therefore, the high-precision digital data shows sampling values at 1 nanosecond intervals.

The nth digital data is digital data obtained by the AD conversion circuit 285 after the nth phase shift. The sampling interval of the AD conversion circuit 284 is 10 nanoseconds. Therefore, the nth digital data shows sampling values at 10 nanosecond intervals.

In this case, the phase shift is performed 10 times for 1 nanosecond, and the sample values of the 1 st to 10 th digital data are arranged in the order of phase, thereby obtaining the inspection signal 112 equivalent to the high-precision digital data.

Effects of mode for carrying out mode 2

In embodiment 2, an unauthorized node can be detected using a low-precision AD converter (AD conversion circuit 285).

It takes time before the phase shift of the base signal is stabilized. In contrast, the base signal output unit 212 instructs the phase shift circuit 286 to shift the phase before starting confirmation of the communication condition of the communication network. Then, the communication status confirmation unit 211 confirms the communication status of the communication network by using the time until the phase shift is stabilized. This can prevent an increase in time until the inspection result is obtained.

Embodiment 3.

A method for coping with a case where network inspection cannot be performed due to the influence of communication conditions will be mainly described with reference to fig. 12 to 14, which is different from embodiment 1.

Description of the structure of Tuliuzhang

The configuration of the network inspection system 100 will be described with reference to fig. 12.

The configuration of the network inspection system 100 is the same as that in embodiment 1 except for a part of the network inspection apparatus 200 (see fig. 1).

The configuration of the network inspection apparatus 200 will be described with reference to fig. 13.

The network inspection apparatus 200 further includes a communication management unit 231. The communication management unit 231 is implemented by software.

The network check program also causes the computer to function as the communication management unit 231.

The other structure is the same as that in embodiment 1 (see fig. 2).

Description of the actions of Tuzhang

The network check method is explained based on fig. 14.

In step S301, the communication status confirmation unit 211 selects 1 unselected communication network. The switching unit 213 switches the connection destination to the selected network.

Step S301 is the same as the processing in embodiment 1 (step S101 and step S102).

In step S311, the communication status confirmation unit 211 confirms the communication status of the selected network.

Step S311 is the same as step S111 in embodiment 1.

In step S312, the communication status confirmation unit 211 determines whether or not the selected network can be checked based on the communication status of the selected network.

Step S312 is the same as step S112 in embodiment 1.

If it is determined that the selected network can be checked, the process proceeds to step S322.

If it is determined that the selected network cannot be checked, the process proceeds to step S321.

In step S321, the communication status confirmation unit 211 notifies the communication management unit 231 of the determination result of the additional check of the selected network.

The communication management unit 231 transmits a communication stop instruction to each node of the selected network. The communication stop instruction is a signal for instructing the stop of communication. For example, the communication management unit 231 transmits a communication stop instruction to the selected network by broadcasting.

Then, the communication management unit 231 notifies the base signal output unit 212 of completion of the communication stop instruction.

In step S322, the basic signal output unit 212 outputs a basic signal to the selected network.

Step S322 is the same as step S121 in embodiment 1.

Steps S331 to S341 are the same as the processing (steps S131 to S141) in embodiment 1.

Effects of mode for carrying out embodiment 3

When the network check cannot be performed under the influence of the communication state, the communication management unit 231 instructs each node of the communication network to stop the communication. Thereby, the network check can be performed.

An example of embodiment 3

Embodiment 3 and embodiment 2 may be combined.

In this case, the network inspection apparatus 200 according to embodiment 3 includes a phase shift circuit 286 that shifts the phase of the base signal. The node determination unit 221 restores the waveform of the inspection signal using 1 or more sampling values of each of the plurality of inspection signals, and performs determination based on the restored waveform.

Embodiment 4.

Regarding a method for coping with a case where contention between a communication signal and an inspection signal occurs, differences from embodiment 1 will be mainly described based on fig. 15 to 19.

Description of the structure of Tuliuzhang

The configuration of the network inspection system 100 will be described with reference to fig. 15.

The configuration of the network inspection system 100 is the same as that in embodiment 1 except for a part of the network inspection apparatus 200 (see fig. 1).

The configuration of the network inspection apparatus 200 will be described with reference to fig. 16.

The network inspection apparatus 200 further includes a communication management unit 232. The communication management unit 232 is implemented by software.

The network check program also causes the computer to function as the communication management unit 232.

The other structure is the same as that in embodiment 1 (see fig. 2).

Description of the actions of Tuzhang

The network check method will be described with reference to fig. 17 and 18.

In step S401, the communication status confirmation unit 211 selects 1 unselected communication network. The switching unit 213 switches the connection destination to the selected network.

Step S401 is the same as the processing in embodiment 1 (step S101 and step S102).

In step S411, the communication status confirmation unit 211 determines whether or not the selected network can be checked based on the communication status of the selected network.

Step S411 is the same as the processing in embodiment 1 (step S111 and step S112).

If it is determined that the selected network can be checked, the process proceeds to step S421.

If it is determined that the selected network cannot be checked, the process proceeds to step S411.

In step S421, the basic signal output unit 212 outputs the basic signal to the selected network.

Step S421 is the same as step S121 in embodiment 1.

In step S431, the node determination unit 221 receives the inspection signal flowing through the selected network.

Step S431 is the same as step S131 in embodiment 1.

The communication status confirmation unit 211 continuously confirms the communication status of the selected network from the start of step S421 to the end of step S431.

In step S441, the communication status confirmation unit 211 determines whether or not communication has occurred in the selected network during the observation time.

The observation time is a time from the start of step S421 to the end of step S431. That is, the observation time is a time from when the base signal is output to the selected network to when the inspection signal is received.

If it is determined that communication has occurred in the selected network, the process proceeds to step S442.

If it is determined that communication has not occurred in the selected network, the process proceeds to step S451.

In step S442, the communication status confirmation unit 211 notifies the node determination unit 221 of the occurrence of communication.

Then, the node determination unit 221 discards the received inspection signal.

In step S443, the communication status confirmation unit 211 notifies the communication management unit 232 of the occurrence of communication.

The communication manager 232 transmits a retransmission instruction to each node of the selected network. The retransmission instruction is a signal for instructing retransmission of a communication signal transmitted within a certain time. For example, the communication manager 232 transmits a retransmission instruction to the selected network by broadcasting.

Then, the communication management unit 232 notifies the communication status confirmation unit 211 of the completion of the retransmission instruction.

After step S443, the process advances to step S411.

Steps S451 to S461 are the same as the processing (steps S132 to S141) in embodiment 1.

The retransmission instruction by the communication management unit 232 will be described with reference to fig. 19.

It is assumed that the communication signal flows through the selected network during a period from the start of the output of the base signal from the network inspection device 200 to the selected network to the completion of the input of the inspection signal from the selected network to the network inspection device 200.

In this case, the communication signal and the check signal compete with each other. As a result, the network inspection device 200 cannot obtain an accurate inspection signal, and each node cannot obtain an accurate communication signal.

Therefore, the node determination unit 221 discards the obtained inspection signal. Further, the communication manager 232 transmits a retransmission instruction to each node. Then, each node retransmits the communication signal.

Effects of mode for carrying out embodiment 4

When contention between the communication signal and the check signal occurs, the communication management unit 232 instructs each node of the communication network to perform retransmission. This can maintain normal communication in the communication network.

Then, when it is determined that the network check is possible, the basic signal output unit 212 newly outputs the basic signal to the communication network. This enables the communication network to be checked accurately.

Embodiments of mode 4

Embodiment 4 and embodiment 2 may be combined.

In this case, the network inspection apparatus 200 according to embodiment 4 includes a phase shift circuit 286 that shifts the phase of the base signal. The node determination unit 221 restores the waveform of the inspection signal using 1 or more sampling values of each of the plurality of inspection signals, and performs determination based on the restored waveform.

Supplement to the embodiments

The hardware configuration of the network inspection apparatus 200 is described based on fig. 20.

The circuit group 208 is a group of the pulse signal circuit 281, the 1 st selector 282, the 2 nd selector 283, and the AD conversion circuits (284, 285).

The network inspection apparatus 200 includes a processing circuit 209.

The processing circuit 209 is hardware that realizes the inspection control unit 210, the inspection unit 220, and the communication management units (231, 232).

The processing circuit 209 may be dedicated hardware or may be the processor 201 that executes a program stored in the memory 202.

Where the processing circuitry 209 is dedicated hardware, the processing circuitry 209 is, for example, a single circuit, a complex circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof.

The ASIC is an abbreviation for Application Specific Integrated Circuit (ASIC).

FPGA is the abbreviation of Field Programmable Gate Array (FPGA).

The network inspection apparatus 200 may include a plurality of processing circuits instead of the processing circuit 209. The plurality of processing circuits share the role of the processing circuit 209.

In the network check device 200, a part of the functions may be implemented by dedicated hardware, and the remaining functions may be implemented by software or firmware.

As such, the processing circuit 209 can be implemented in hardware, software, firmware, or a combination thereof.

The embodiments are illustrative of preferred embodiments and are not intended to limit the technical scope of the present invention. Embodiments may be implemented in part or in combination with other implementations. The steps described with reference to the flowcharts and the like may be changed as appropriate.

Circuits such as the pulse signal circuit 281, the 1 st selector 282, the 2 nd selector 283, and the AD conversion circuits (284, 285) may be provided outside the network inspection device 200.

The network check device 200 may also be implemented by a plurality of devices. For example, the network inspection apparatus 200 may be realized by an apparatus that realizes the inspection control unit 210, an apparatus that realizes the inspection unit 220, and an apparatus that realizes the communication management units (231, 232).

The "section" as an element of the network inspection apparatus 200 may be rewritten as "processing" or "step".

Description of the reference symbols

100 network inspection system, 101 1 st network, 102 nd network, 2 nd network, 111 basic signal, 112 inspection signal, 113 reference signal, 200 network inspection device, 201 processor, 202 memory, 203 auxiliary storage device, 204 input/output interface, 205 communication interface, 208 circuit group, 209 processing circuit, 210 inspection control unit, 211 communication status confirmation unit, 212 basic signal output unit, 213 switching unit, 220 inspection unit, 221 node determination unit, 222 result output unit, 231 communication management unit, 232 communication management unit, 281 pulse signal circuit, 282 1 st selector, 283 nd 2 nd selector, 284AD conversion circuit, 285AD conversion circuit, 286 phase shift circuit, 290 storage unit.