JP2019186605A - Network control system and relay device - Google Patents

Abstract

To provide a network control technique capable of waking up a node by synchronizing it in a virtual network unit while using a mechanism of WOL.SOLUTION: A network control system comprises: a plurality of switching hubs; a plurality of terminal devices constructing a plurality of virtual networks; and an Ethernet signal line connecting between each terminal device and each relay device, and the relay devices. Each terminal device determines an identifier of each virtual network which is desired to be waked up, generates a first frame containing a sequential specific value and the determined identifier embedded just after a sequential direct constant value, and transmits them to each relay device. Each relay device extracts the identifier in the first frame, specifies a MAC address of each terminal device belonging to the identifier extracted by using a table, and rewrites the specific value in the first frame to the specified MAC address to transmit to each terminal device in a broadcast.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a virtual vehicle-mounted network control technology.

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

JP 2013-77892 A

  By the way, although a plurality of control devices (hereinafter referred to as ECUs) are mounted on the vehicle, a group of ECUs having the same type of function is not necessarily mounted physically close to each other. For this reason, if a sub-network is formed for each group of ECUs having the same type of function, wiring may be complicated. Therefore, as a vehicle network, a communication network according to the Ethernet (registered trademark) protocol is used to form a subnetwork by connecting to a relay device for each group of ECUs close to the mounting position, and a group of ECUs having similar 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, not in units of actual sub-networks. Therefore, the relay device must relay the wake-up frame in order to wake up ECUs belonging to a 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 wake-up frame in which all MAC addresses of ECUs to be woken up are entered. However, in general, a relay device mounted on a vehicle is low-grade and has a low processing capability. Therefore, a wake-up frame including all MAC addresses may not be processed.

  In such a vehicle network, when the method described in Patent Document 1 is applied 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 for changing 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.

  The present disclosure has been made in view of the above circumstances, and a network that can wake up a node synchronously in units of virtual networks without changing the configuration of an existing node by using a 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 (11-14, 21-24, 31-34), and a plurality of terminal devices. And signal lines (L 1, L 2, L 3, L 11, L 12, L 13) that connect the relay devices and any of the plurality of relay devices. The signal line is a signal line for communicating a frame according to the Ethernet (registered trademark) protocol. The plurality of terminal devices form a plurality of virtual networks. The terminal device includes a determination unit, a first frame transmission unit, and a wakeup unit. The determination unit determines an identifier of a virtual network to be woken up. The first frame transmission unit generates a first frame including a specific value that is consecutive for a predetermined number of times set in advance, and an identifier that is embedded immediately after the specific value that is determined by the determination unit and is connected to the first frame. The first frame is transmitted to the relay device. The wakeup unit puts itself into a wakeup state when receiving a frame containing its own MAC address continuously a predetermined number of times. The relay device includes a table, an extraction unit, a specifying unit, and a second frame transmission unit. The table describes the correspondence between the identifier of the virtual network to which each terminal device connected to itself belongs and the MAC address of each terminal device. When receiving the first frame, the extraction unit identifies a continuous specific value and extracts an identifier embedded immediately after the continuous specific value. The specifying unit uses the table to specify the MAC address of the terminal device belonging to the identifier extracted by the extracting unit. The second frame transmitting unit rewrites the specific value in the first frame with the MAC address specified by the specifying unit, generates a second frame including a MAC address that continues a predetermined number of times, and is connected to itself Broadcast to the device.

  According to the present disclosure, the first frame having a simple structure in which the specific value continues for a predetermined number of times is generated and transmitted by the terminal device, and the first frame is received by the switching hub. A simple structure in which a specific value continues for a predetermined number of times can be mechanically identified without detailed analysis of the frame. Therefore, even if the processing capability is low, the switching hub can identify a specific value that continues for a predetermined number of times, and mechanically extract the identifier embedded immediately after the continuous specific value from the first frame.

  Furthermore, the switching hub includes a table that describes the correspondence between the identifier of the virtual network to which the terminal device belongs and the MAC address of the terminal device. For this reason, when the configuration of the virtual network changes, it can be dealt with by simply rewriting the table possessed by the switching hub, so there is no need to change the configuration of an existing terminal device that is a network node. And a switching hub specifies the MAC address of the terminal device which belongs to the extracted identifier using the table which it has. Further, the switching hub rewrites the specific value of the first frame with the specified MAC address to generate the second frame, and transmits the second frame to the control device connected to the switching hub. Therefore, by using the WOL mechanism, the terminal device can be woken up synchronously in units of virtual networks without changing the configuration of the existing terminal device.

  Note that the reference numerals in parentheses described in this column and in the claims indicate the correspondence with the specific means described in the embodiment described later as one aspect, and the technical scope of the present disclosure 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 with which a switching hub is provided. It is a figure which shows the structure of a special frame. It is a flowchart which shows the procedure of the relay process of the flame | frame which a switching hub performs. It is a flowchart which shows the procedure of the transmission process of the special frame which a terminal device performs. It is a flowchart which shows the procedure of the reception process of the magic packet which a terminal device performs.

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

  The switching hubs 310, 320, and 330 are mounted at positions separated from each other, and are respectively connected to the switching hub 200 by Ethernet signal lines L1, L2, and L3 for communicating frames in accordance with the Ethernet (registered trademark) protocol. It is connected. Further, four terminal devices are connected to the switching hubs 310, 320, and 330 through 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. The switching hub 320 is connected to four terminal devices 21 to 24 that are physically mounted near the switching hub 320 by an Ethernet signal line L12. The switching hub 330 is connected to four terminal devices 31 to 34 that are physically mounted near the switching hub 330 by an Ethernet signal line L13.

  The switching hubs 200, 310, 320, and 330 are low-level relay devices that do not include a microcomputer (hereinafter referred to as a microcomputer), and realize various functions by hardware. Specifically, the switching hubs 200, 310, 320, and 330 relay frames. The switching hub 200 relays frames among the switching hub 310, the switching hub 320, and the switching hub 330. Each of the switching hubs 310, 320, and 330 transmits a frame transmitted from a subordinate terminal device connected thereto to another subordinate terminal device or the switching hub 200. In addition, the switching hubs 310, 320, and 330 transmit the frame received from the switching hub 200 to the subordinate terminal devices. Furthermore, the switching hubs 200, 310, 320, and 330 include a timer configured by hardware.

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

  The terminal devices 11 to 14, 21 to 24, and 31 to 34 form a virtual LAN (hereinafter referred to as “VLAN”) that is a virtual network independent of the physical connection form. Specifically, the three terminal devices 11, 12, and 21 form a VLAN 1. The three terminal devices 13, 22, and 31 form a VLAN 2. In addition, the three terminal devices 14, 23, and 32 form a VLAN 3. Further, the three terminal devices 24, 33 and 34 form a VLAN 4. VLANs 1 to 4 are assigned to VLANs 1 to 4, respectively. VLAN-ID is an identifier for identifying a VLAN.

  The VLANs 1 to 4 are functional groups configured by terminal devices having the same type of function. For example, the VLANs 1 to 4 include a travel control group configured by terminal devices that execute various travel controls, an entertainment group configured by terminal devices that perform various entertainment-related controls, and various user interface-related controls. A user interface group composed of terminal devices that execute the above.

  The switching hubs 310, 320, and 330 include a routing table that describes correspondences between subordinate terminal device IDs, subordinate terminal device MAC addresses, and VLAN-IDs to which the subordinate terminal devices belong. FIG. 2 shows a routing table provided in the switching hub 310. In the routing table provided 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-IDs to which the terminal devices 11 to 14 belong are associated.

<2. Processing>
<2-1. Wake-up process>
Next, the overall flow of the wake-up process in the network control system 100 will be described with reference to FIG. The network control system 100 wakes up the terminal device 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 wake-up signal to all the switching hubs to wake up all the switching hubs. The terminal device 11 wakes up by an input by the door key operation of the vehicle or an ignition on.

  Subsequently, in S <b> 2, 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 transmission destination MAC address, a transmission 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 a specific value defined at the time of hardware design of each switching hub continues 16 times. 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 a terminal device belonging to the same VLAN 1 as the terminal device 11 itself. The special frame has a structure in which the MAC address of 16 consecutive magic packets is replaced with a specific value, and has a structure close to that of the magic packet. In the present embodiment, the special frame corresponds to the first frame.

  Subsequently, in S <b> 3, the switching hub 310 transmits the received special frame to the switching hub 200. 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 a 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 extract a VLAN-ID by mechanically identifying a pattern in which a predetermined specific value continues. Then, the switching hubs 310, 320, and 330 specify the MAC addresses of subordinate terminal devices belonging to the extracted VLAN-ID using the routing tables 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 include a subordinate terminal device belonging to 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 is continuous 16 times, and the VLAN-ID. A frame including a magic packet is generated. In the present 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 devices by broadcasting. Of the terminal devices under the control of the magic packet, the terminal device whose MAC address contained in the magic packet matches its own MAC address wakes up using the WOL function.

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

Subsequently, in S8, when the count value of the timer reaches a preset threshold value, the switching hubs 310, 320, and 330 enter the sleep state.
<2-2. Frame relay processing>
Next, a procedure of frame relay processing 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 S <b> 10, the switching hub 300 receives a wake-up signal transmitted from a subordinate terminal device or the switching hub 200.
Subsequently, in S20, the switching hub 300 wakes up and starts counting by a timer at regular intervals.

  Subsequently, in S30, when the switching hub 300 receives the wakeup signal from the terminal device under its control in S10, the switching hub 300 transmits the wakeup signal to the switching hub 200, and the remaining two via the switching hub 200. A wakeup signal is transferred to the switching hub 300. Thereafter, the switching hub 300 proceeds to the process of S40. When the switching hub 300 receives a wake-up 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. If the switching hub 300 determines in S40 that the frame is not a special frame, the process proceeds to S50. If the switching hub 300 determines that the frame is a special frame, the process proceeds to S60.

In S50, the switching hub 300 reads the destination terminal device of the frame, routes the frame to the destination terminal device, and proceeds to the processing 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 are transmitted via the switching hub 200. Forward special frame to Thereafter, the switching hub 300 proceeds to the process of S70. If the switching hub 300 receives a special frame from the switching hub 200 in S40, the switching hub 300 proceeds directly to the processing of S70.

Subsequently, in S70, the switching hub 300 identifies a specific pattern in which the specific value in the received special frame is continuous, 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 described in its own routing table. In S80, if the switching hub 300 determines that it is not described in the routing table, the process proceeds to S120. If it is determined that it is described in the routing table, the process proceeds to S90.

  Subsequently, in S90, the switching hub 300 specifies the MAC address of the subordinate terminal device belonging to the VLAN-ID extracted in S70, 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 address is continuous. When the switching hub 300 identifies the MAC addresses of a plurality of terminal devices in S90, the switching hub 300 generates a magic packet for each identified MAC address.

Subsequently, in S110, the switching hub 300 transmits the magic packet generated in S100 to all terminal devices under the broadcast.
Subsequently, in S120, the switching hub 300 counts up a timer.

  Subsequently, in S130, the switching hub 300 determines whether any signal is received. If the switching hub 300 determines in S130 that the signal has been received, the process proceeds to S140. 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 process of S120. Thereby, the count 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 needs to reach a preset threshold value. When the switching hub 300 determines in S150 that the count value has not reached the threshold value, the process returns to S120. Thereby, the count of the period when communication is not detected is continued.

  On the other hand, when 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, the switching hub 300 puts itself into a sleep state. This process is complete | finished above.

  Note that, like the switching hub 300, the switching hub 200 starts counting a timer at regular intervals after wakeup, and counts a period during which communication is not detected. Then, the switching hub 200 puts itself in the sleep state when the count value of the timer reaches a preset threshold value.

  In this embodiment, the process of S70 corresponds to the function of the extraction unit, and the process of S90 corresponds to the function of the specifying unit. Further, the processing of S100 and S110 corresponds to the function of the second frame transmission unit. Further, the process of S60 corresponds to the function of the transfer unit. Further, the process of S160 corresponds to the function of the sleep unit, and the process of S140 corresponds to the function of the reset unit.

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

In S200, the terminal device A determines a VLAN-ID to be woken up.
Subsequently, in S210, the terminal device A generates a special frame including a broadcast address and a specific pattern in which specific values are continuous, 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 hub 200, 310, 320, 330.
Subsequently, in S230, the terminal device A transmits the wakeup signal generated in S220 to the switching hub to which the terminal device A 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 transmitted from the switching hub 200 to the remaining two switching hubs. This wakes up all the switching hubs.

  Subsequently, in S240, the terminal device A transmits the special frame generated in S210 to the switching hub to which the terminal device A 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. Thereby, all the switching hubs receive the special frame. This process is received.

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

<2-4. Magic packet reception processing>
Next, the procedure of magic packet reception processing 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. Below, the terminal device which receives a magic packet among terminal devices 11-14, 21-24, 31-34 is called terminal device B.

First, in S300, the terminal device B receives a magic packet from the switching hub to which the terminal device B is connected.
Subsequently, in S310, the terminal apparatus 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 it is determined that the MAC addresses do not match, the terminal device B proceeds to the process of S330 and continues the sleep state. This process is complete | finished above.

In the present embodiment, the processing of S310 and S320 corresponds to the function of the wakeup 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 continues 16 times is generated and transmitted by the terminal device, and the special frames are received by the switching hubs 310, 320, and 330. A simple structure in which a specific value continues 16 times can be mechanically identified without detailed analysis of the frame. Therefore, even if the processing capability is low, the switching hubs 310, 320, and 330 identify a specific value that continues 16 times, and mechanically extract the VLAN-ID embedded immediately after the continuous specific value from the special frame. be able to.

  Furthermore, 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. For this reason, if the VLAN configuration changes, it can be dealt with by simply rewriting the routing table possessed, so there is no need 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 that belongs to the extracted VLAN-ID using the routing table possessed by the switching hub. Further, the switching hubs 310, 320, and 330 rewrite the specific value of the special frame with the specified MAC address to generate a magic packet, and transmit the magic packet to the terminal device under its control. Therefore, by using the WOL mechanism, the terminal device can be woken up synchronously on a VLAN basis without changing the configuration of the existing terminal device.

  (2) A switching hub that has received a special frame from a subordinate terminal device forwards the special frame to another switching hub, so even terminal devices connected to different switching hubs belong to the same VLAN. If it is a terminal device, it can wake up synchronously.

(3) Since each switching hub goes into a sleep state when communication is not detected for a predetermined period, it is possible to suppress power consumption.
(4) If each switching hub detects communication during the count of the timer, the switching hub can reset the value of the counter to zero to perform counting again during a period in which communication is not detected.

  (5) The switching hubs 310, 320, and 330 generate magic packets that are existing standard wake-up frames from the special frames. Therefore, the network control system 100 can be easily realized.

(Other embodiments)
As mentioned above, although the form for implementing this indication was demonstrated, this indication is not limited to the above-mentioned embodiment, and can carry out various modifications.

  (A) In the above embodiment, the network control system 100 includes the switching hub 200 that relays frames between the switching hubs 310, 320, and 330. However, the network control system 100 may not include the switching hub 200. If the switching hubs 310, 320, and 300 are connected to the other two switching hubs via Ethernet communication lines, frames can be exchanged without using the switching hub 200.

  (B) In the above embodiment, the special pattern of the special frame is a pattern in which the specific value continues 16 times, but the number of times that the specific value continues may not be 16. 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 a pattern that continues any number of times, even if the specific value is not a pattern that continues 16 times. In this case, the frame generated from the special frame by the switching hubs 310, 320, and 330 may not be a magic packet.

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

  (D) A plurality of functions of one constituent element in the above embodiment may be realized by a plurality of constituent elements, or a single function of one constituent element may be realized by a plurality of constituent elements. . Further, a plurality of functions possessed by a plurality of constituent elements may be realized by one constituent element, or one function realized by a plurality of constituent elements may be realized by one constituent element. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified only by the wording described in the claims are embodiments of the present disclosure.

  Reference numerals 11 to 14, 21 to 24, 31 to 34, terminal devices, 100, a network control system, 200, 310, 320, 330, switching hubs, L1, L2, L3, L11, L12, L13, signal lines.

Claims (10)

A plurality of relay devices (310, 320, 330);
A plurality of terminal devices (11-14, 21-24, 31-34) respectively connected to any of the plurality of relay devices;
A signal line for connecting a frame according to the Ethernet (registered trademark) protocol between each of the plurality of terminal devices and any one of the plurality of relay devices and between the relay devices. (L1, L2, L3, L11, L12, L13),
The plurality of terminal devices form a plurality of virtual networks,
The terminal device
A determination unit for determining an identifier of a virtual network to be woken up;
A first frame including a specific value that is set a predetermined number of times in advance and the identifier that is determined by the determination unit and embedded immediately after the continuous specific value is generated, and the first frame is connected to the first frame. A first frame transmission unit for transmitting the first frame to a relay device;
A wakeup unit that wakes itself up when it receives a frame containing its own MAC address continuously for the predetermined number of times, and
The relay device is
A table in which 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 extracting unit for identifying the continuous specific value and extracting the identifier embedded immediately after the continuous specific value when the first frame is received;
Using the table, a specifying unit that specifies the MAC address of the terminal device belonging to the identifier extracted by the extracting unit;
Rewriting the specific value in the first frame to the MAC address specified by the specifying unit, generating a second frame including the MAC address that continues for the predetermined number of times, and the terminal connected to itself A second frame transmission unit that broadcasts to the device,
Network control system. The relay device is
A transfer unit that 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;
When the count value of the timer reaches a preset threshold, a sleep unit that puts itself in a sleep state,
The network control system according to claim 1 or 2. The relay device is
A reset unit that resets the count value of the timer to zero when the communication is detected;
The network control system according to claim 3. The predetermined number of times is 16,
The second frame is a magic packet;
The network control system of any one of Claims 1-4. A relay device,
A plurality of terminal devices are connected by signal lines for communicating frames in accordance with the Ethernet protocol, and the plurality of terminal devices together with a plurality of terminal devices connected to other relay devices by the signal lines, Forming multiple virtual networks,
A table in which 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 receiving a first frame including a specific value that is consecutive for a predetermined number of times set in advance and the identifier embedded immediately after the continuous specific value, the continuous specific value is identified, and the continuous An extraction unit for extracting the identifier embedded immediately after the specific value to be
Using the table, a specifying unit that specifies the MAC address of the terminal device belonging to the identifier extracted by the extracting unit;
Rewriting the specific value in the first frame to the MAC address specified by the specifying unit, generating a second frame including the MAC address that continues for the predetermined number of times, and the terminal connected to itself A second frame transmission unit that broadcasts to the device,
Relay equipment A transfer unit that 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;
When the count value of the timer reaches a preset threshold, a sleep unit that puts itself in a sleep state,
The relay device according to claim 6 or 7. A reset unit that resets the count value of the timer to zero when the communication is detected;
The relay device according to claim 8. The predetermined number of times is 16,
The second frame is a magic packet;
The relay device according to any one of claims 6 to 9.

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