JP6992655B2 - Network control system and relay equipment - Google Patents

Description

The present disclosure relates to a control technique for a virtualized in-vehicle network.

There is a Wake on LAN (WOL) technology that sends a wake-up frame to a node on a LAN to wake up the node remotely. The wake-up control method described in Patent Document 1 has a packet structure similar to that of a packet used in normal communication as a wake-up frame, and uses a packet having a specific data pattern set in advance. .. Then, in the above method, the node is set so as to wake up when a packet having a specific data pattern is recognized.

Japanese Unexamined Patent Publication No. 2013-77892

By the way, although a plurality of control devices (hereinafter referred to as ECUs) are mounted on a vehicle, a group of ECUs having the same type of functions is not always mounted at a close physical position. Therefore, if an attempt is made to form a sub-network for each group of ECUs having the same type of function, wiring may become complicated. Therefore, as a vehicle network, a communication line conforming to the Ethernet (registered trademark) protocol is used to connect to a relay device for each group of ECUs that are close to each other to form a sub-network, and a group of ECUs having the same functions. A network that forms a virtual network can be considered.

In such a vehicle network, it is desired to wake up the ECU synchronously in units of virtual networks instead of units of actual sub-networks. Therefore, the relay device must relay the wake-up frame in order to wake up the ECU belonging to the specific virtual network.

In such a vehicle network, in order to wake up the ECU in units of virtual networks, it is conceivable to use a wakeup frame containing all the MAC addresses of the ECUs to be waked up. However, in general, the relay device mounted on the vehicle is low-grade and has low processing capacity, so that it may not be possible to process the wake-up frame containing all the MAC addresses.

Further, in such a vehicle network, when the method described in Patent Document 1 is applied in order to wake up the ECU in units of virtual networks, a specific data pattern is set in the ECU for each virtual network. Therefore, when the configuration of the virtual network changes, a function to change the setting of the ECU is required. That is, it is necessary to change the configuration of the existing ECU so as to add such a function.

This disclosure was made in view of the above circumstances, and is a network that can wake up nodes in synchronization with each virtual network without changing the configuration of existing nodes by using the WOL mechanism. The purpose is to provide control technology.

One aspect of the present disclosure is a network control system, which includes a plurality of relay devices (310, 320, 330), a plurality of terminal devices (11 to 14, 21 to 24, 31 to 34), and a plurality of terminal devices. A signal line (L1, L2, L3, L11, L12, L13) connecting each of the above and any one of the plurality of relay devices and between the relay devices is provided. The signal line is a signal line for communicating a frame according to the Ethernet® protocol. A plurality of terminal devices form a plurality of virtual networks. The terminal device includes a determination unit, a first frame transmission unit, and a wake-up unit. The decision unit determines the identifier of the virtual network to be woken up. The first frame transmission unit generates a first frame including a predetermined number of consecutive specific values set in advance and an identifier determined by the determination unit and embedded immediately after the continuous specific values, and is connected by itself. The first frame is transmitted to the relay device being used. The wake-up unit puts itself in the wake-up state when it receives a frame in which its MAC address is continuously included a predetermined number of times. The relay device includes a table, an extraction unit, a specific unit, and a second frame transmission unit. The table describes the correspondence between the identifier of the virtual network to which each of the terminal devices connected to itself belongs and the MAC address of each terminal device. When the first frame is received, the extraction unit identifies consecutive specific values and extracts an identifier embedded immediately after the continuous specific values. The specific unit uses a table to specify the MAC address of the terminal device belonging to the identifier extracted by the extraction unit. The second frame transmitter rewrites the specific value in the first frame to the MAC address specified by the specific unit, generates the second frame including the MAC address consecutively a predetermined number of times, and the terminal connected to itself. Broadcast to the device.

According to the present disclosure, a terminal device generates and transmits a first frame having a simple structure in which a specific value is continuous a predetermined number of times, and a switching hub receives the first frame. A simple structure in which specific values are continuous a predetermined number of times can be mechanically identified without detailed analysis in the frame. Therefore, the switching hub can identify the specific value consecutively a predetermined number of times even if the processing capacity is low, and can mechanically extract the identifier embedded immediately after the continuous specific value from the first frame.

Further, the switching hub includes a table describing the correspondence between the identifier of the virtual network to which the terminal device belongs and the MAC address of the terminal device. Therefore, when the configuration of the virtual network changes, it can be dealt with by simply rewriting the table possessed by the switching hub, so that it is not necessary to change the configuration of the existing terminal device which is a node of the network. Then, the switching hub identifies the MAC address of the terminal device belonging to the extracted identifier by using the possessed table. Further, the switching hub rewrites the specific value of the first frame into the specified MAC address to generate the second frame, and transmits the second frame to the control device connected to itself. Therefore, by using the WOL mechanism, it is possible to wake up the terminal device in synchronization with each virtual network without changing the configuration of the existing terminal device.

In addition, the reference numerals in parentheses described in this column and the scope of claims indicate the correspondence with the specific means described in the embodiment described later as one embodiment, and the technical scope of the present disclosure is defined. It is not limited.

It is a figure which shows the structure of a network control system. It is a figure which shows the routing table provided in the switching hub. It is a figure which shows the structure of a special frame. It is a flowchart which shows the procedure of the relay processing of a frame executed by a switching hub. It is a flowchart which shows the procedure of the transmission processing of a special frame executed by a terminal apparatus. It is a flowchart which shows the procedure of the reception processing of the magic packet executed by a terminal apparatus.

Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.
<1. Configuration>
The configuration of the network control system 100 mounted on the vehicle according to the present embodiment will be described with reference to FIG. The network control system 100 includes switching hubs 200, 310, 320, 330, and terminal devices 11 to 14, 21 to 24, 31 to 34.

The switching hubs 310, 320, and 330 are mounted at positions separated from each other, and are connected to the switching hub 200 by the Ethernet signal lines L1, L2, and L3 for communicating the frame according to the Ethernet (registered trademark) protocol, respectively. It is connected. Further, four terminal devices are connected to the switching hubs 310, 320, and 330 by Ethernet signal lines, respectively.

Specifically, the switching hub 310 is connected to four terminal devices 11 to 14 physically mounted near the switching hub 310 by an Ethernet signal line L11. Further, the switching hub 320 is connected to four terminal devices 21 to 24 physically mounted near the switching hub 320 by an Ethernet signal line L12. Further, the switching hub 330 is connected to four terminal devices 31 to 34 physically mounted near the switching hub 330 by an Ethernet signal line L13.

The switching hubs 200, 310, 320, and 330 are low-grade relay devices that are not equipped with a microcomputer (hereinafter referred to as a microcomputer), and realize various functions by hardware. Specifically, the switching hubs 200, 310, 320, 330 relay frames. The switching hub 200 relays a frame between the switching hub 310, the switching hub 320, and the switching hub 330. The switching hubs 310, 320, and 330 each transmit a frame transmitted from a subordinate terminal device connected to the switching hub 310, 320, and 330 to another subordinate terminal device or the switching hub 200. Further, the switching hubs 310, 320, 330 transmit the frame received from the switching hub 200 to the subordinate terminal device. Further, the switching hubs 200, 310, 320, 330 include a timer configured by hardware.

The terminal devices 11 to 14, 21 to 24, 31 to 34 are in-vehicle devices including a microcomputer having a CPU, RAM, ROM, and the like, and are, for example, various ECUs. Various functions of the terminal devices 11 to 14, 21 to 24, 31 to 34 are realized by at least one of software and hardware.

The terminal devices 11 to 14, 21 to 24, 31 to 34 form a virtual LAN (hereinafter referred to as VLAN) which is a virtual network independent of the physical connection form. Specifically, the three terminal devices 11, 12, and 21 form the VIN1. Further, the three terminal devices 13, 22, and 31 form the WLAN 2. Further, the three terminal devices 14, 23 and 32 form the VIN3. Further, the three terminal devices 24, 33, and 34 form the VIN4. VLAN-IDs 1 to 4 are assigned to VLANs 1 to 4, respectively. The VLAN-ID is an identifier that identifies the VLAN.

WLANs 1 to 4 are functional groups composed of terminal devices having the same type of function. For example, WLANs 1 to 4 include a driving control group composed of terminal devices that execute various driving controls, an entertainment group composed of terminal devices that execute various entertainment-related controls, and various user interface-related controls. It is a user interface group composed of terminal devices that execute.

The switching hubs 310, 320, and 330 include a routing table in which the correspondence between the ID of the subordinate terminal device, the MAC address of the subordinate terminal device, and the VLAN-ID to which the subordinate terminal device belongs is described. FIG. 2 shows a routing table included in the switching hub 310. In the routing table included in the switching hub 310, the terminal device IDs of the terminal devices 11 to 14, the MAC addresses of the terminal devices 11 to 14, and the VLAN-ID to which the terminal devices 11 to 14 belong are associated with each other.

<2. Processing>
<2-1. Wake-up process>
Next, the entire flow of the wake-up process in the network control system 100 will be described with reference to FIG. In the network control system 100, the terminal device is waked up for each VLAN.

First, in S1, the terminal device 11 wakes up while all the switching hubs and all the terminal devices are in the sleep state. Then, the terminal device 11 sends a wakeup signal to all the switching hubs to wake up all the switching hubs. The terminal device 11 wakes up by input by operating the door key of the vehicle or by turning on the ignition.

Subsequently, in S2, the terminal device 11 generates a special frame and transmits the generated special frame to the switching hub 310. FIG. 3 shows the structure of the special frame. The special frame is an Ethernet frame and includes a destination MAC address, a source MAC address, a tag, an Ethernet type, and a data body.

The data body includes a broadcast address that repeats FF six times, a specific pattern, and a VLAN-ID embedded immediately after the specific pattern. The specific pattern is a pattern in which the specific value defined at the time of hardware design of each switching hub is continuous 16 times. The VLAN-ID indicates the VLAN to which the terminal device to be woken up belongs. Here, the terminal device 11 embeds a VLAN-ID indicating the VLAN 1 in the data body in order to wake up the terminal device belonging to the same VLAN 1 as itself. The special frame has a structure in which the MAC address 16 times in a row of the magic packet is replaced with a specific value, and has a structure similar to that of the magic packet. In this embodiment, the special frame corresponds to the first frame.

Subsequently, in S3, the switching hub 310 transmits the received special frame to the switching hub 200. Further, the switching hub 200 transmits the received special frame to the switching hubs 320 and 330, respectively.

Subsequently, in S4, the switching hubs 310, 320, and 330 identify the specific pattern in the special frame, and extract the VLAN-ID embedded immediately after the special pattern. The switching hubs 310, 320, and 330 can mechanically identify a pattern in which predetermined specific values are continuous, and mechanically extract the VLAN-ID. Then, the switching hubs 310, 320, and 330 each specify the MAC address of the subordinate terminal device belonging to the extracted VLAN-ID by using the routing table possessed by each. Specifically, the switching hub 310 specifies the MAC address of the terminal device 12 belonging to VLAN-ID = 1, and the switching hub 320 specifies the MAC address of the terminal device 21 belonging to VLAN-ID = 1. Since the switching hub 330 does not have a terminal device under the control of VLAB-ID = 1, the process of S7 described later is started.

Subsequently, in S5, the switching hubs 310 and 320 rewrite the specific value in the special frame to the MAC address specified in S4, and change the broadcast address, the pattern in which the MAC address continues 16 times, and the VLAN-ID. Generates a frame containing, that is, a magic packet. In this embodiment, the magic packet corresponds to the second frame.

Subsequently, in S6, the switching hubs 310 and 320 transmit the generated magic packet to the subordinate terminal device by broadcasting. Then, among the terminal devices under the control of receiving the magic packet, the terminal device whose MAC address included in the magic packet matches its own MAC address wakes up by using the WOL function.

Subsequently, in S7, the switching hubs 310, 320, and 330 reset the timer and then start counting, and the timer counts the period during which communication is not detected at regular intervals.

Subsequently, in S8, the switching hubs 310, 320, and 330 put themselves into a sleep state when the count value of the timer reaches a preset threshold value.
<2-2. Frame relay processing>
Next, a procedure for relay processing of frames executed by the switching hubs 310, 320, and 330 will be described with reference to the flowchart of FIG. Hereinafter, the switching hubs 310, 320, and 330 are collectively referred to as a switching hub 300.

First, in S10, the switching hub 300 receives the wake-up signal transmitted from the subordinate terminal device or the switching hub 200.
Subsequently, in S20, the switching hub 300 wakes up and starts counting by the timer at regular intervals.

Subsequently, in S30, when the switching hub 300 receives the wakeup signal from the subordinate terminal device in S10, the switching hub 300 transmits the wakeup signal to the switching hub 200, and the remaining two via the switching hub 200. The wakeup signal is transferred to the switching hub 300. After that, the switching hub 300 proceeds to the process of S40. Further, when the switching hub 300 receives the wakeup signal from the switching hub 200 in S10, the switching hub 300 proceeds to the process of S40 as it is.

In S40, the switching hub 300 receives the frame and determines whether or not the received frame is a special frame. In S40, if it is determined that the switching hub 300 is not a special frame, the process proceeds to S50, and if it is determined to be a special frame, the process proceeds to S60.

In S50, the switching hub 300 reads the terminal device at the destination of the frame, routes the frame to the terminal device at the destination, and proceeds to the process of S120.
On the other hand, in S60, when the switching hub 300 receives the special frame from the subordinate terminal device in S40, the switching hub 300 transmits the special frame to the switching hub 200, and the remaining two switching hubs 300 pass through the switching hub 200. Transfer a special frame to. After that, the switching hub 300 proceeds to the process of S70. Further, when the switching hub 300 receives a special frame from the switching hub 200 in S40, the switching hub 300 proceeds to the process of S70 as it is.

Subsequently, in S70, the switching hub 300 identifies a specific pattern in which specific values are continuous in the received special frame, and extracts the VLAN-ID immediately after the specific pattern.
Subsequently, in S80, the switching hub 300 determines whether or not the VLAN-ID extracted in S70 is listed in the routing table possessed by the switching hub 300. In S80, if it is determined that the switching hub 300 is not described in the routing table, the process proceeds to S120, and if it is determined that the switching hub 300 is described in the routing table, the process proceeds to S90.

Subsequently, in S90, the switching hub 300 identifies the MAC address of the subordinate terminal device belonging to the VLAN-ID extracted in S70 by using its own routing table.

Subsequently, in S100, the switching hub 300 rewrites the continuous specific value in the special frame to the MAC address specified in S90, and creates a magic packet including a pattern in which the MAC addresses are continuous. When the switching hub 300 specifies the MAC addresses of a plurality of terminal devices in S90, the switching hub 300 generates a magic packet for each of the specified MAC addresses.

Subsequently, in S110, the switching hub 300 transmits the magic packet generated in S100 to all the terminal devices under its control by broadcasting.
Subsequently, in S120, the switching hub 300 counts up the timer.

Subsequently, in S130, the switching hub 300 determines whether or not any signal has been received. In S130, if it is determined that the switching hub 300 has received the signal, the process proceeds to S140, and if it is determined that the signal has not been received, the process proceeds to S150.

In S140, the switching hub 300 resets the timer to 0 and returns to the processing of S120. As a result, the counting by the timer is restarted from 0.
On the other hand, in S150, the switching hub 300 determines whether or not the count value of the timer reaches a preset threshold value. If the switching hub 300 determines in S150 that the count value has not reached the threshold value, the process returns to S120. As a result, the counting of the period during which communication is not detected is continued.

On the other hand, if the switching hub 300 determines in S150 that the count value has reached the threshold value, the process proceeds to S160. In S160, since the switching hub 300 has not detected communication for a predetermined period, it puts itself into a sleep state. This is the end of this process.

Similar to the switching hub 300, the switching hub 200 starts counting the timer at regular intervals after wake-up, and counts the period during which communication is not detected. Then, the switching hub 200 puts itself into a sleep state when the count value of the timer reaches a preset threshold value.

Further, in the present embodiment, the processing of S70 corresponds to the function of the extraction unit, and the processing of S90 corresponds to the function of the specific unit. Further, the processing of S100 and S110 corresponds to the function of the second frame transmission unit. Further, the processing of S60 corresponds to the function of the transfer unit. Further, the processing of S160 corresponds to the function of the sleep unit, and the processing of S140 corresponds to the function of the reset unit.

<2-3. Special frame transmission processing>
Next, the procedure of the transmission processing of the special frame executed by the terminal devices 11 to 14, 21 to 24, 31 to 34 will be described with reference to the flowchart of FIG. In the following, among the terminal devices 11 to 14, 21 to 24, 31 to 34, the terminal device already in the wake-up state is referred to as the terminal device A.

In S200, the terminal device A determines the VLAN-ID to be woken up.
Subsequently, in S210, the terminal device A generates a special frame in which the broadcast address and the specific pattern in which the specific values are continuous are included and the VLAN-ID determined in S200 is embedded immediately after the specific pattern.

Subsequently, in S220, the terminal device A generates a wake-up signal for wake-up of the switching hubs 200, 310, 320, 330.
Subsequently, in S230, the terminal device A transmits the wakeup signal generated in S220 to the switching hub to which it is connected. The wake-up signal is transmitted from the switching hub to which the terminal device A is connected to the switching hub 200, and is also transmitted from the switching hub 200 to the remaining two switching hubs. This wakes up all switching hubs.

Subsequently, in S240, the terminal device A transmits the special frame generated in S210 to the switching hub to which it is connected. The special frame is transmitted from the switching hub to which the terminal device A is connected to the switching hub 200, and is transmitted from the switching hub 200 to the remaining two switching hubs. This causes all switching hubs to receive special frames. This process is received.

In this embodiment, the processing of S200 corresponds to the function of the determination unit, and the processing of S210 and S240 corresponds to the function of the first frame transmission unit.

<2-4. Magic packet reception processing>
Next, the procedure of receiving the magic packet executed by the terminal devices 11 to 14, 21 to 24, and 31 to 34 will be described with reference to the flowchart of FIG. In the following, among the terminal devices 11 to 14, 21 to 24, 31 to 34, the terminal device that receives the magic packet is referred to as a terminal device B.

First, in S300, the terminal device B receives the magic packet from the switching hub to which it is connected.
Subsequently, in S310, the terminal device B determines whether or not the MAC address included in the magic packet matches its own MAC address. If the terminal device B determines that the MAC addresses match, the terminal device B proceeds to the process of S320 and wakes up. On the other hand, if the terminal device B determines that the MAC addresses do not match, the terminal device B proceeds to the process of S330 and continues the sleep state. This is the end of this process.

In this embodiment, the processing of S310 and S320 corresponds to the function of the wake-up unit.
<3. Effect>
According to the first embodiment described above, the following effects can be obtained.

(1) A special frame having a structure in which a specific value is continuously generated 16 times is generated and transmitted by the terminal device, and the special frame is received by the switching hubs 310, 320, and 330. A simple structure in which a specific value is continuous 16 times can be mechanically identified without detailed analysis in the frame. Therefore, the switching hubs 310, 320, 330 identify the specific value 16 times in a row even if the processing capacity is low, and mechanically extract the VLAN-ID embedded immediately after the continuous specific value from the special frame. be able to.

Further, the switching hubs 310, 320, and 330 include a routing table that describes the correspondence between the VLAN-ID to which the subordinate terminal device belongs and the MAC address of the terminal device. Therefore, when the configuration of the VLAN is changed, it can be dealt with only by rewriting the possessed routing table, so that it is not necessary to change the configuration of the existing terminal device. Then, the switching hubs 310, 320, and 330 specify the MAC address of the terminal device belonging to the extracted VLAN-ID by using the routing table possessed by the switching hubs 310, 320, and 330. Further, the switching hubs 310, 320, and 330 rewrite the specific value of the special frame into the specified MAC address to generate a magic packet, and transmit the magic packet to the subordinate terminal device. Therefore, by using the WOL mechanism, it is possible to wake up the terminal device in synchronization with each VLAN without changing the configuration of the existing terminal device.

(2) Since a switching hub that receives a special frame from a subordinate terminal device transfers the special frame to another switching hub, even a terminal device connected to a different switching hub belongs to the same VLAN. If it is a terminal device, it can be woken up synchronously.

(3) Since each switching hub goes into a sleep state when communication is not detected for a predetermined period, power consumption can be suppressed.
(4) When each switching hub detects communication during timer counting, it can reset the value of the counter to zero to redo the counting during the period when communication is not detected.

(5) The switching hubs 310, 320, 330 generate a magic packet, which is an existing standard wake-up frame, from a special frame. Therefore, it is easy to realize the network control system 100.

(Other embodiments)
Although the embodiment for carrying out the present disclosure has been described above, the present disclosure is not limited to the above-described embodiment, and can be variously modified and carried out.

(A) In the above embodiment, the network control system 100 includes a switching hub 200 that relays a frame between the switching hubs 310, 320, and 330, but the switching hub 200 may not be provided. If the switching hubs 310, 320, and 300 are each connected to the other two switching hubs via an Ethernet communication line, frames can be exchanged without going through the switching hub 200.

(B) In the above embodiment, the special pattern of the special frame is a pattern in which the specific value is continuous 16 times, but the number of times the specific value is continuous does not have to be 16 times. The number of consecutive specific values may be any number. The switching hubs 310, 320, and 330 can be identified as long as the specific value is not a continuous pattern 16 times, but is a continuous pattern an arbitrary number of times. In this case, the frame generated by the switching hubs 310, 320, 330 from the special frame does not have to be a magic packet.

(C) In the above embodiment, the switching hubs 200, 310, 320, 330 are not provided with a microcomputer, but may be provided with a microcomputer. Even if the switching hubs 200, 310, 320, and 330 include a microcomputer, the processing shown in FIG. 4 can be executed while the microcomputer is in the sleep state.

(D) A plurality of functions possessed by one component in the above embodiment may be realized by a plurality of components, or one function possessed by one component may be realized by a plurality of components. .. Further, a plurality of functions possessed by the plurality of components may be realized by one component, or one function realized by the plurality of components may be realized by one component. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added or replaced with the configuration of the other above embodiment. It should be noted that all aspects included in the technical idea specified only by the wording described in the claims are embodiments of the present disclosure.

11-14, 21-24, 31-34 ... Terminal device, 100 ... Network control system, 200, 310, 320, 330 ... Switching hub, L1, L2, L3, L11, L12, L13 ... Signal line.

Claims (10)

With multiple relay devices (310, 320, 330),
A plurality of terminal devices (11 to 14, 21 to 24, 31 to 34) connected to any of the plurality of relay devices, respectively.
A signal line connecting each of the plurality of terminal devices and any of the plurality of relay devices, and between the relay devices, for communicating a frame according to the Ethernet (registered trademark) protocol. (L1, L2, L3, L11, L12, L13)
The plurality of terminal devices form a plurality of virtual networks, and the plurality of terminal devices form a plurality of virtual networks.
The terminal device is
A decision-making unit that determines the identifier of the virtual network you want to wake up,
The first frame including the predetermined number of consecutive specific values and the identifier determined by the determination unit and embedded immediately after the continuous specific value is generated, and the user is connected to the first frame. A first frame transmitter that transmits the first frame to a relay device,
It is provided with a wake-up unit that puts itself in a wake-up state when it receives a frame in which its own MAC address is continuously included a predetermined number of times.
The relay device is
A table in which the correspondence between the identifier of the virtual network to which each of the terminal devices connected to itself belongs and the MAC address of each of the terminal devices is described.
An extraction unit that identifies the continuous specific value when the first frame is received and extracts the identifier embedded immediately after the continuous specific value.
Using the table, a specific unit that identifies the MAC address of the terminal device belonging to the identifier extracted by the extraction unit, and a specific unit.
The specific value in the first frame is rewritten to the MAC address specified by the specific unit, a second frame including the MAC address consecutive for a predetermined number of times is generated, and the terminal connected to itself. A second frame transmitter that broadcasts to the device is provided.
Network control system. The relay device is
A transfer unit is provided which transfers the first frame to another relay device when the first frame is received from the terminal device connected to the terminal device.
The network control system according to claim 1. The relay device is
A timer that counts the period when communication is not detected at regular intervals,
A sleep unit that puts itself into a sleep state when the count value of the timer reaches a preset threshold value is provided.
The network control system according to claim 1 or 2. The relay device is
A reset unit for resetting the count value of the timer to zero when the communication is detected is provided.
The network control system according to claim 3. The predetermined number of times is 16 times.
The second frame is a magic packet,
The network control system according to any one of claims 1 to 4. It ’s a relay device,
A plurality of terminal devices are connected by a signal line for communicating a frame according to the Ethernet protocol, and the plurality of terminal devices are connected to another relay device together with a plurality of terminal devices connected by the signal line. It forms multiple virtual networks and
A table in which the correspondence between the identifier of the virtual network to which each of the terminal devices connected to itself belongs and the MAC address of each of the terminal devices is described.
When the first frame including the predetermined number of consecutive specific values and the identifier embedded immediately after the continuous specific value is received, the continuous specific value is identified and the continuous. An extraction unit that extracts the identifier embedded immediately after the specific value to be used,
Using the table, a specific unit that identifies the MAC address of the terminal device belonging to the identifier extracted by the extraction unit, and a specific unit.
The specific value in the first frame is rewritten to the MAC address specified by the specific unit, a second frame including the MAC address consecutive for a predetermined number of times is generated, and the terminal connected to itself. A second frame transmitter that broadcasts to the device is provided.
Relay equipment A transfer unit is provided which transfers the first frame to another relay device when the first frame is received from the terminal device connected to the terminal device.
The relay device according to claim 6. A timer that counts the period when communication is not detected at regular intervals,
A sleep unit that puts itself into a sleep state when the count value of the timer reaches a preset threshold value is provided.
The relay device according to claim 6 or 7. A reset unit for resetting the count value of the timer to zero when the communication is detected is provided.
The relay device according to claim 8. The predetermined number of times is 16 times.
The second frame is a magic packet,
The relay device according to any one of claims 6 to 9.

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