JP2020141183A - Communication device and communication method - Google Patents

Abstract

To provide a communication device that can shorten a time until network communication is started.SOLUTION: A communication device of the present invention includes: a communication unit that can communicate with a network device via a relay device; and a control unit that controls operation of the communication unit so that the communication unit transmits one or more search packets including itself as a transmission target to the relay device, and starts communication with the network device after receiving any of the one or more search packets.SELECTED DRAWING: Figure 3

Description

The present invention relates to a communication device and a communication method for communicating with a network device via a relay device.

In network communication, communication is often performed via a relay device. Some relay devices detect the presence or absence of a loop-shaped transmission line by performing a route search operation using the spanning tree protocol (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2004-297475

In a communication device, it is desired to start network communication in a short time after the route search operation by the spanning tree protocol is performed, and it is expected that the time until the network communication is started is further shortened.

It is desirable to provide a communication device and a communication method capable of shortening the time until the start of network communication.

The communication device according to the embodiment of the present invention includes a communication unit and a control unit. The communication unit is configured to be able to communicate with the network device via the relay device. The control unit causes the communication unit to transmit one or more search packets including itself as a transmission target to the relay device, and to start communication with the network device after receiving one or more of the search packets. It is configured to control the operation of the communication unit.

The communication method according to the embodiment of the present invention is to transmit one or more search packets including itself as a transmission target to the relay device, and to relay after receiving either one or a plurality of search packets. Includes initiating communication with a network device via the device.

According to the communication device and the communication method according to the embodiment of the present invention, one or a plurality of search packets including itself as a transmission target are transmitted to the relay device, and either one or a plurality of search packets is received. Since the communication with the network device is started later, the time until the network communication is started can be shortened.

It is a block diagram which shows one configuration example of the communication system which concerns on 1st Embodiment. It is a flowchart which shows one operation example of the communication device shown in FIG. It is a timing chart which shows one operation example of the communication system shown in FIG. It is a block diagram which shows one configuration example of the communication system which concerns on the modification of the 1st Embodiment. It is a flowchart which shows one operation example of the communication apparatus shown in FIG. It is a timing chart which shows one operation example of the communication system shown in FIG. It is a block diagram which shows one configuration example of the communication system which concerns on 2nd Embodiment. It is a flowchart which shows one operation example of the communication apparatus shown in FIG. It is a timing chart which shows one operation example of the communication system shown in FIG. It is a timing chart which shows the other operation example of the communication system shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The explanation will be given in the following order.
1. 1. First Embodiment 2. Second embodiment

<1. First Embodiment>
[Configuration example]
FIG. 1 shows a configuration example of a communication system 1 including a communication device according to the first embodiment of the present invention. The communication system 1 is configured to include a redundant network. Since the communication method according to the embodiment of the present invention is embodied by the embodiment, it will be described together. The communication system 1 includes a plurality of relay devices 11 (three relay devices 11A, 11B, 11C in this example), a DHCP (Dynamic Host Configuration Protocol) server 12, an information processing device 13, and an image forming device 14. ing.

The relay device 11 is a hub that relays network communication. The relay device 11 has a plurality of ports (not shown), and is configured to be able to connect to a plurality of network devices via these ports. The relay device 11 controls communication using the spanning tree protocol. Specifically, the relay device 11 detects the presence or absence of a loop-shaped transmission line by performing a route search operation using this spanning tree protocol. Then, when there is a loop-shaped transmission path, the relay device 11 controls communication so that the network packet is not looped and transmitted.

In this example, the relay device 11A is connected to the relay devices 11B and 11C and the DHCP server 12 via, for example, a LAN (Local Area Network) cable. The relay device 11B is connected to the relay devices 11A and 11C and the information processing device 13 via, for example, a LAN cable. The relay device 11C is connected to the relay devices 11A and 11B and the image forming device 14 via, for example, a LAN cable. As shown in FIG. 1, the relay devices 11A, 11B, and 11C include a loop-shaped transmission line. That is, the relay devices 11A, 11B, and 11C form a redundant network (network NET).

The relay devices 11A, 11B, and 11C detect a loop-shaped transmission line by performing a route search operation using the spanning tree protocol, for example, when the network device is newly electrically connected to the network NET. During the period in which the route search operation is performed, the relay devices 11A, 11B, and 11C block communication with devices other than the relay devices 11A, 11B, and 11C. Then, the relay devices 11A, 11B, and 11C are adapted to control communication based on the processing result of this route search operation so that the network packet is not transmitted in a loop.

The DHCP server 12 is configured to assign an IP (Internet Protocol) address to a network device connected to a network NET, such as an information processing device 13 or an image forming device 14. The DHCP server 12 is connected to the relay device 11A in this example. Then, the DHCP server 12 communicates with the network device via the network NET, and assigns an IP address to the network device based on the request from the network device.

The information processing device 13 is a so-called personal computer in this example. The information processing device 13 is connected to the relay device 11B in this example. The information processing device 13 generates print data based on the user's operation, and transmits the print data to the image forming device 14 via the network NET.

The image forming apparatus 14 is configured to form an image on a recording medium such as paper based on print data. The image forming apparatus 14 is connected to the relay device 11C in this example. The image forming apparatus 14 forms an image on a recording medium based on the print data transmitted from the information processing apparatus 13 via the network NET. The NetBIOS name of the image forming apparatus 14 is set to "Printer-A". The image forming device 14 includes a communication device 20, an image forming control unit 17, an image forming unit 18, and a power supply unit 19.

The communication device 20 is connected to the relay device 11C and is configured to communicate with the DHCP server 12 and the information processing device 13 via the network NET. Specifically, the communication device 20 acquires the IP address assigned by the DHCP server 12 by communicating with the DHCP server 12 via the network NET. Then, for example, the communication device 20 uses this IP address to communicate with the information processing device 13 via the network NET to receive the print data transmitted from the information processing device 13. .. The communication device 20 has a communication unit 21, a storage unit 22, and a communication control unit 23.

The communication unit 21 is configured to communicate with the DHCP server 12 and the information processing device 13 by transmitting and receiving network packets via the network NET.

Further, as will be described later, in the communication unit 21, when the relay devices 11A, 11B, 11C are performing the route search operation and the communication with the devices other than the relay devices 11A, 11B, 11C is blocked, the communication unit 21 is blocked. A plurality of search packets P for searching the image forming apparatus 14 which is the own device are intermittently transmitted. At that time, the communication unit 21 transmits the plurality of search packets P by broadcasting. In this example, the search packet P is a network packet in the form of "NetBIOS Name Service". In this search packet P, the "Queries" parameter is set to "Printer-A" which is the NetBIOS name of the own device. The communication unit 21 broadcasts the search packet P using port 137 of the UDP (User Datagram Protocol) protocol.

In this example, a network packet having the format of "NetBIOS Name Service" is applied to the search packet P, but the present invention is not limited to this, and is used in, for example, the "WSD (Web Services on Devices)" protocol. A network packet or a network packet used in the "multicast DNS" protocol may be applied to the search packet P.

The storage unit 22 is a non-volatile memory. The search packet information INF1 is stored in the storage unit 22. The search packet information INF1 includes information about the search packet P transmitted by the communication unit 21.

The communication control unit 23 is configured to control the communication operation of the communication device 20. The communication control unit 23 is configured by using, for example, a processor, a RAM (Random Access Memory), or the like. The communication control unit 23 controls the communication unit 21 to transmit a network packet for requesting the allocation of an IP address to the DHCP server 12. When the communication unit 21 receives a network packet containing information about the assigned IP address transmitted from the DHCP server 12, the communication control unit 23 receives the assigned IP address based on the network packet. Is acquired, and network settings are made based on this IP address. Then, the communication control unit 23 controls the communication unit 21 to communicate with the network device using this IP address. For example, when the communication unit 21 communicates with the information processing device 13 using this IP address and receives the print data transmitted from the information processing device 13, the communication control unit 23 uses the print data. It is designed to be supplied to the image formation control unit 17.

Further, for example, in the communication control unit 23, when the relay devices 11A, 11B, 11C are performing the route search operation and the communication with the devices other than the relay devices 11A, 11B, 11C is blocked, the storage unit 23 is stored. Based on the search packet information INF1 stored in 22, the communication unit 21 controls to intermittently transmit a plurality of search packets P. Then, when the communication unit 21 receives any one of the plurality of search packets P, the communication control unit 23 controls the communication unit 21 to stop the transmission of the search packet P and start network communication. It is designed to do.

The image forming control unit 17 is configured to control the operation of the image forming unit 18 based on the print data supplied from the communication device 20.

The image forming unit 18 is configured to form an image on a recording medium such as paper based on an instruction from the image forming control unit 17.

The power supply unit 19 is configured to generate power supply power used in the communication device 20, the image formation control unit 17, and the image formation unit 18 based on the AC power supplied from the AC power supply AC such as a commercial power supply. Will be done. The power supply unit 19 generates power supply power, for example, when the user turns on the power supply switch. Then, the power supply unit 19 supplies the generated power supply power to the communication device 20, the image formation control unit 17, and the image formation unit 18.

With this configuration, in the communication system 1, the relay devices 11A, 11B, and 11C are performing the route search operation, and the period during which communication with the devices other than the relay devices 11A, 11B, and 11C is blocked (communication cutoff period T). In, the communication device 20 intermittently transmits a plurality of search packets P. Then, when the communication device 20 receives any one of the plurality of search packets P, it determines that the communication cutoff period T has ended, stops the transmission of the search packet P, and communicates with the network device. To start. As a result, in the communication system 1, the time until the network communication is started can be shortened.

Here, the communication unit 21 corresponds to a specific example of the "communication unit" in the present invention. The communication control unit 23 corresponds to a specific example of the "control unit" in the present invention. The relay device 11C corresponds to a specific example of the "relay device" in the present invention. The DHCP server 12 corresponds to a specific example of the "network device" in the present invention. The search packet P corresponds to a specific example of the "search packet" in the present invention.

[Action and action]
Subsequently, the operation and operation of the communication device 20 of the present embodiment will be described.

(Overview of overall operation)
First, the overall operation outline of the communication system 1 will be described with reference to FIG. The relay devices 11A, 11B, 11C relay the network communication. The communication device 20 of the image forming device 14 acquires the IP address assigned by the DHCP server 12 by communicating with the DHCP server 12 via the network NET. The communication device 20 of the image forming apparatus 14 receives the print data transmitted from the information processing apparatus 13 by communicating with the information processing apparatus 13 via the network NET. Then, the image forming apparatus 14 forms an image on a recording medium such as paper based on the print data.

The relay devices 11A, 11B, and 11C detect a loop-shaped transmission line by performing a route search operation using the spanning tree protocol when the network device is newly electrically connected to the network NET. During the period in which the route search operation is performed, the relay devices 11A, 11B, and 11C block communication with devices other than the relay devices 11A, 11B, and 11C. During this period (communication cutoff period T), the communication device 20 of the image forming device 14 intermittently transmits a plurality of search packets P. Then, when the communication device 20 receives any one of the plurality of search packets P, the communication device 20 stops the transmission of the search packet P and starts network communication.

(Detailed operation)
FIG. 2 shows an operation example of the communication device 20 when the user turns on the power switch of the image forming device 14. FIG. 3 shows an operation example of the communication system 1, (A) shows the operation of the relay devices 11A, 11B, 11C, (B) shows the operation of the communication device 20, and (C) shows the communication. The transmission data of the device 20 is shown, and (D) shows the reception data of the communication device 20. In the following, a case where the relay device 11C and the image forming apparatus 14 are electrically connected to each other by turning on the power switch of the image forming apparatus 14 will be described as an example, but the present invention is limited to this. It's not a thing. For example, the user electrically connects the relay device 11C and the image forming device 14 to each other by physically connecting the image forming device 14 in which the power switch is on to the relay device 11C using a LAN cable. The same applies to the case.

When the user turns on the power switch of the image forming apparatus 14, the power supply unit 19 is used in the communication device 20, the image forming control unit 17, and the image forming unit 18 based on the AC power supplied from the AC power supply AC. Start generating power (step S101).

In the example of FIG. 3, the relay devices 11A, 11B, and 11C perform the network communication relay operation in the period before the timing t1 (FIG. 3A). Further, since the power switch of the image forming apparatus 14 is in the off state during this period, the power supply power is not supplied to the communication device 20 (FIG. 3B).

Then, at the timing t1, the user turns on the power switch of the image forming apparatus 14. As a result, the power supply power generated by the power supply unit 19 is supplied to the communication device 20, and the communication device 20 starts operating. As a result, the communication device 20 is in a communicable state (FIG. 3 (B)).

When the communication device 20 starts operating in this way, the image forming device 14 is electrically connected to the relay device 11C. When it is detected that the relay device 11C is electrically connected to the image forming device 14, the relay devices 11A, 11B, and 11C perform a route search operation using the spanning tree protocol (FIG. 3 (A)). As a result, the relay devices 11A, 11B, and 11C cut off communication with devices other than the relay devices 11A, 11B, and 11C. In this way, the communication cutoff period T starts.

Next, the communication device 20 transmits the search packet P (step S102). Specifically, the communication control unit 23 generates a search packet P based on the search packet information INF1 stored in the storage unit 22, and the communication unit 21 transmits the search packet P by broadcasting.

Next, the communication control unit 23 of the communication device 20 confirms whether or not the communication unit 21 has received the search packet P transmitted in step S102 (step S103). If the search packet P has not been received (“N” in step S103), the process returns to step S102, and steps S102 and S103 are repeated until the communication device 20 receives the search packet P.

In the example of FIG. 3, at the timing t2, the communication device 20 transmits the first search packet P (FIG. 3 (C)). Since the relay devices 11A, 11B, and 11C block communication with devices other than the relay devices 11A, 11B, and 11C, the search packet P disappears. Therefore, since the communication device 20 does not receive this search packet P, the communication device 20 transmits the next search packet P at the timing t3. In this way, in this example, the communication device 20 intermittently transmits a plurality of search packets P at predetermined time intervals (for example, 3 second intervals).

When the search packet P is received in step S103 (“Y” in step S103), the communication device 20 starts network communication (step S104). That is, when the communication device 20 receives the search packet P, it determines that the communication cutoff period T has ended, and starts network communication.

In the example of FIG. 3, at the timing t4, the relay devices 11A, 11B, and 11C end the route search operation (FIG. 3 (A)). As a result, the relay devices 11A, 11B, and 11C release the interruption of communication with the devices other than the relay devices 11A, 11B, and 11C. In this way, the communication cutoff period T ends. Then, the relay devices 11A, 11B, and 11C resume the relay operation of the network communication. The relay devices 11A, 11B, and 11C control communication based on the processing result of this route search operation so that the network packet is not transmitted in a loop.

At the subsequent timing t5, the communication device 20 transmits the search packet P (FIG. 3 (C)). Since the search packet P is for searching the own device and is broadcast, the relay device 11C transmits the search packet P to the relay devices 11A and 11B, and transmits the search packet P to the communication device 20. Also send. Therefore, the communication device 20 receives the search packet P at the timing t6 (FIG. 3 (D)). As a result, the communication device 20 determines that the communication cutoff period T has ended, and starts the network communication COM (FIGS. 3 (C) and 3 (D)).

After this timing t6, the communication device 20 transmits a network packet for requesting IP address allocation to the DHCP server 12, and a network packet including information about the assigned IP address transmitted from the DHCP server 12. To receive. Then, the communication control unit 23 of the communication device 20 acquires the IP address assigned by the DHCP server 12 based on the network packet, and sets the network based on the IP address. After that, the communication device 20 can perform network communication using this IP address. For example, the communication device 20 receives the print data transmitted from the information processing device 13 by communicating with the information processing device 13 via the relay devices 11A, 11B, 11C (network NET). Then, the image forming apparatus 14 forms an image on a recording medium such as paper based on the print data.

This is the end of this flow.

As described above, when the image forming apparatus 14 is electrically connected to the relay device 11C, the communication device 20 starts transmitting a plurality of search packets P and receives any one of the plurality of search packets P. In that case, network communication is started. As a result, in the communication device 20, the time from the end of the communication cutoff period T to the start of network communication can be shortened.

That is, for example, the communication device may be configured so that the communication device starts network communication when a predetermined standby time elapses after the image forming device is electrically connected to the relay device. In this case, for example, even if the route search operation is completed in a short time, the communication device does not start network communication until this standby time elapses, so that network communication is started after the communication cutoff period T ends. May take longer. Further, when the network configuration is changed, the time for performing the route search operation changes, and the length of the communication cutoff period T may change. Therefore, for example, when the administrator tries to set the waiting time appropriately in order to shorten the time until the network communication is started, the administrator has to set the waiting time every time the network configuration is changed. Since it is necessary to set, it takes time and effort for the administrator.

On the other hand, in the communication device 20, when the image forming device 14 is electrically connected to the relay device 11C, a plurality of search packets P are started to be transmitted, and any one of the plurality of search packets P is received. I started network communication. As a result, the communication device 20 can start the network communication after confirming that the communication cutoff period T has ended. Therefore, the timing for starting the network communication is set according to the length of the communication cutoff period T. It can be set appropriately. Specifically, when the length of the communication cutoff period T is short, the timing to start the network communication is advanced, and when the length of the communication cutoff period T is long, the timing to start the network communication is delayed. be able to. As described above, in the communication device 20, the timing for starting the network communication can be appropriately set according to the length of the communication cutoff period T. Therefore, in the communication device 20, after the communication cutoff period T ends. The time until network communication is started can be shortened. Further, even if the network configuration is changed, the communication device 20 can appropriately set the timing for starting the network communication according to the length of the communication cutoff period T, so that the administrator can set the standby time. Since it is not necessary to set it, the trouble of the administrator can be reduced.

[effect]
As described above, in the present embodiment, when the image forming apparatus is electrically connected to the relay device, a plurality of search packets are started to be transmitted, and when any one of the plurality of search packets is received. Since the network communication is started, the timing for starting the network communication can be appropriately set according to the length of the communication cutoff period, so that the time until the network communication is started can be shortened. ..

[Modification 1-1]
In the above embodiment, as shown in FIG. 2, the network communication is started when the search packet P transmitted by itself is received, but the present invention is not limited to this. Instead of this, for example, network communication may be started even when a network packet other than the search packet P is received. The present modification will be described in detail below.

FIG. 4 shows a configuration example of the communication system 1A according to the present modification. The communication system 1A includes a plurality of relay devices 11 (three relay devices 11A, 11B, 11C in this example), an information processing device 13, and an image forming device 14A. The image forming apparatus 14A has a communication apparatus 20A. The communication device 20A has a communication control unit 23A. The communication control unit 23A is configured to perform communication using a preset IP address. That is, the communication control unit 23 according to the above embodiment is controlled to perform communication using the IP address assigned from the DHCP server 12, but the communication control unit 23A according to this modification is preset. It is designed to control communication using an IP address. Further, the communication control unit 23A controls the communication unit 21 to intermittently transmit a plurality of search packets P based on the search packet information INF1 stored in the storage unit 22 during the communication cutoff period T. Then, when the communication unit 21 receives the network packet, the communication control unit 23A controls the communication unit 21 to stop the transmission of the search packet P and start the network communication.

FIG. 5 shows an operation example of the communication device 20A.

When the user turns on the power switch of the image forming apparatus 14A, the power supply unit 19 is used in the communication device 20A, the image forming control unit 17, and the image forming unit 18 based on the AC power supplied from the AC power supply AC. Start generating power (step S101).

Next, the communication device 20A transmits the search packet P (step S102).

Next, the communication device 20A confirms whether or not the network packet has been received (step S113). The network packet may be the search packet P transmitted in step S102, the packet Q transmitted from the information processing device 13, or the packet Q transmitted from a network device (not shown). Good. The packet Q may be a unicast packet or a broadcast packet. If no network packet has been received (“N” in step S113), the process returns to step S102, and steps S102 and S113 are repeated until the communication device 20A receives the network packet.

When the network packet is received in step S113 (“Y” in step S103), the communication device 20A starts network communication (step S104). That is, when the communication device 20A receives the network packet, it determines that the communication cutoff period T has ended and starts network communication.

This is the end of this flow.

FIG. 6 shows an operation example of the communication system 1A. In this example, as in the case of the above embodiment (FIG. 3), at the timing t4, the relay devices 11A, 11B, 11C end the route search operation, and the communication cutoff period T ends (FIG. 5 (A). )).

At the subsequent timing t16, the communication device 20A receives the packet Q (FIG. 6 (D)). Specifically, for example, the information processing device 13 transmits this packet Q to the image forming device 14A immediately after the timing t4, and the network NET relays this packet Q to communicate with the image forming device 14A. The device 20A receives this packet Q at the timing t16. As a result, the communication device 20A determines that the communication cutoff period T has ended, and starts the network communication COM (FIGS. 6 (C) and 6 (D)).

Here, the communication control unit 23A corresponds to a specific example of the "control unit" in the present invention. The information processing device 13 corresponds to a specific example of the "network device" in the present invention. The packet Q corresponds to a specific example of the "packet" in the present invention.

[Modification 1-2]
In the above embodiment, the communication device 20 starts network communication when one of the plurality of transmitted search packets P is received, but the present invention is not limited to this, and for example, a plurality of transmitted packets P are transmitted. Network communication may be started after receiving two or more search packets P out of the search packets P of the above.

[Modification 1-3]
In the above embodiment, when the communication device 20 receives any one of the plurality of transmitted search packets P, the communication device 20 stops the transmission of the search packet P, but the transmission is not limited to this, for example. After receiving any one of the plurality of transmitted search packets P, some more search packets P may be transmitted.

<2. Second Embodiment>
Next, the communication system 2 according to the second embodiment will be described. In the present embodiment, in the communication cutoff period T, the communication device starts transmitting a plurality of search packets P intermittently after a waiting time elapses after the communication device and the relay device 11C are electrically connected to each other. It is a thing. The components substantially the same as those of the communication system 1 according to the first embodiment are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

FIG. 7 shows a configuration example of the communication system 2. The communication system 2 includes an image forming device 34. The image forming device 34 has a communication device 40. The communication device 40 has a storage unit 42 and a communication control unit 43.

The storage unit 42 stores the search packet information INF1 and the waiting time information INF2. The standby time information INF2 is about the length of the waiting time (standby time T2) from when the communication device 40 and the relay device 11C are electrically connected to each other until the plurality of search packets P are started to be intermittently transmitted. Contains information.

The communication control unit 43 is configured to control the communication operation of the communication device 40. The communication control unit 43 has a time detection unit 44. The time detection unit 44 is configured to measure the reception time T1 from when the communication device 40 and the relay device 11C are electrically connected to each other until the search packet P is received. Then, the time detection unit 44 calculates the standby time T2 to be used when the communication device 40 is next electrically connected to the relay device 11C based on the reception time T1. The communication control unit 43 stores the information about the standby time T2 in the storage unit 42 as the standby time information INF2.

For example, the communication control unit 43 stores the communication device 40 and the relay device 11C in the storage unit 42 after the standby time T2 indicated by the standby time information INF2 stored in the storage unit 42 has elapsed after the communication device 40 and the relay device 11C are electrically connected to each other. Based on the stored search packet information INF1, the communication unit 21 controls to intermittently transmit a plurality of search packets P. Then, when the communication unit 21 receives any one of the plurality of search packets P, the communication control unit 43 causes the communication unit 21 to stop the transmission of the search packet P and start network communication. It is designed to be controlled.

Here, the communication control unit 43 corresponds to a specific example of the "control unit" in the present invention. The storage unit 42 corresponds to a specific example of the “storage unit” in the present invention.

FIG. 8 shows an operation example of the communication device 40 when the user turns on the power switch of the image forming device 34.

When the user turns on the power switch of the image forming apparatus 34, the power supply unit 19 is used in the communication device 40, the image forming control unit 17, and the image forming unit 18 based on the AC power supplied from the AC power supply AC. Start generating power (step S101).

Next, the communication control unit 43 of the communication device 40 acquires information about the standby time T2 based on the standby time information INF2 stored in the storage unit 42 (step S201).

Next, the communication control unit 43 of the communication device 40 confirms whether or not the standby time T2 has elapsed since the communication device 40 and the relay device 11C are electrically connected to each other (step S202). If the standby time T2 has not yet elapsed (“N” in step S202), the communication control unit 43 repeats this step S202 until the standby time T2 elapses.

When the waiting time T2 has elapsed in step S202 (“Y” in step S202), the communication device 40 transmits the search packet P (step S102). Specifically, the communication control unit 43 generates a search packet P based on the search packet information INF1 stored in the storage unit 42, and the communication unit 21 transmits the search packet P by broadcasting.

Next, the communication control unit 43 of the communication device 40 confirms whether or not the communication unit 21 has received the search packet P transmitted in step S102 (step S103). If the search packet P has not been received (“N” in step S103), the process returns to step S102, and steps S102 and S103 are repeated until the communication device 40 receives the search packet P.

When the search packet P is received in step S103 (“Y” in step S103), the communication device 40 starts network communication (step S104). That is, when the communication device 40 receives the search packet P, it determines that the communication cutoff period T has ended, and starts network communication.

Next, the time detection unit 44 of the communication device 40 detects the reception time T1 from when the communication device 40 and the relay device 11C are electrically connected to each other until the search packet P is received (step S203).

Then, the time detection unit 44 calculates the standby time T2 to be used when the communication device 40 is next electrically connected to the relay device 11C based on the reception time T1 detected in step S203, and performs communication control. The unit 43 stores the information about the waiting time T2 in the storage unit 42 as the waiting time information INF2 (step S204).

This is the end of this flow.

9A and 9B show an operation example of the communication system 2, where (A) and (E) show the operations of the relay devices 11A, 11B and 11C, and (B) and (F) show the operations of the communication device 40. , (C) and (G) indicate the transmission data of the communication device 40, and (D) and (H) indicate the reception data of the communication device 40. (A) to (D) show the operation when the user turns on the power switch of the image forming apparatus 34, and (E) to (H) show the operation when the user then turns on the power switch of the image forming apparatus 34. Shows the operation when it is turned on.

In the examples of FIGS. 9A to 9D, the user turns on the power switch of the image forming apparatus 34 at the timing t21. As a result, the power supply power generated by the power supply unit 19 is supplied to the communication device 40, the communication device 40 starts operating, and the communication device 40 is in a communicable state (FIG. 9B). As a result, when the communication device 40 and the relay device 11C are electrically connected to each other, the relay devices 11A, 11B, and 11C perform a route search operation using the spanning tree protocol (FIG. 9A). In this way, the communication cutoff period T starts.

The communication control unit 43 acquires information about the standby time T2 based on the standby time information INF2 stored in the storage unit 42. Then, at the timing t22 when the standby time T2 has elapsed since the communication device 40 and the relay device 11C are electrically connected to each other, the communication device 40 transmits the first search packet P (FIG. 9C). In this example, the communication device 40 intermittently transmits a plurality of search packets P thereafter.

At the timing t23, the relay devices 11A, 11B, and 11C end the route search operation (FIG. 9A), and the communication cutoff period T ends. The relay devices 11A, 11B, and 11C resume the relay operation of network communication. At the subsequent timing t24, the communication device 40 transmits the search packet P (FIG. 9 (C)), and at the timing t25, the communication device 40 receives the search packet P (FIG. 9 (D)). As a result, the communication device 40 determines that the communication cutoff period T has ended, and starts the network communication COM (FIGS. 9 (C) and 9 (D)).

The time detection unit 44 detects the reception time T1 (timing t21 to t25) from when the communication device 40 and the relay device 11C are electrically connected to each other until the search packet P is received. Then, the time detection unit 44 calculates the standby time T2 to be used when the communication device 40 is next electrically connected to the relay device 11C based on the reception time T1. Specifically, the time detection unit 44 calculates the standby time T2 so that the standby time T2 is shorter than the reception time T1. Then, the communication control unit 43 stores the information about the standby time T2 in the storage unit 42 as the standby time information INF2.

Then, for example, after a while, the user turns off the power switch of the image forming apparatus 34.

Then, as shown in FIGS. 9E to 9H, the user turns on the power switch of the image forming apparatus 34 again at the timing t31. As a result, the power supply power generated by the power supply unit 19 is supplied to the communication device 40, the communication device 40 starts operating, and the communication device 40 is in a communicable state (FIG. 9F). As a result, when the communication device 40 and the relay device 11C are electrically connected to each other, the relay devices 11A, 11B, and 11C perform a route search operation using the spanning tree protocol (FIG. 9 (E)). In this way, the communication cutoff period T starts.

The communication control unit 43 acquires information about the standby time T2 based on the standby time information INF2 stored in the storage unit 42. Then, at the timing t32 when the standby time T2 has elapsed since the communication device 40 and the relay device 11C are electrically connected to each other, the communication device 40 transmits the first search packet P (FIG. 9 (G)). In this example, the communication device 40 intermittently transmits a plurality of search packets P thereafter.

At the timing t33, the relay devices 11A, 11B, and 11C end the route search operation (FIG. 9E), and the communication cutoff period T ends. The relay devices 11A, 11B, and 11C resume the relay operation of network communication. That is, in this example, the route search operation is completed in a shorter time than the previous operations shown in FIGS. 9A to 9D. At the subsequent timing t34, the communication device 40 transmits the search packet P (FIG. 9 (G)), and at the timing t35, the communication device 40 receives the search packet P (FIG. 9 (H)). As a result, the communication device 40 determines that the communication cutoff period T has ended, and starts the network communication COM (FIGS. 9 (G) and 9 (H)).

Then, the time detection unit 44 detects the reception time T1 (timing t31 to t35) from when the communication device 40 and the relay device 11C are electrically connected to each other until the search packet P is received, and this reception time T1 Next, the standby time T2 to be used when the communication device 40 is electrically connected to the relay device 11C is calculated based on the above. Then, the communication control unit 43 stores the information about the standby time T2 in the storage unit 42 as the standby time information INF2.

FIG. 10 shows another operation example of the communication system 2. 10 (A) to 10 (D) are the same as FIGS. 9 (A) to 9 (D).

In the example of FIGS. 10 (E) to 10 (H), the relay devices 11A, 11B, and 11C perform a route search operation using the spanning tree protocol during the period of timings t51 to t52 (FIG. 10 (E)). In this example, the route search operation is completed in a shorter time than in the cases of FIGS. 9 (E) to 9 (H).

The communication device 40 transmits the first search packet P at the timing t53 when the waiting time T2 has elapsed since the communication device 40 and the relay device 11C are electrically connected to each other (FIG. 10 (G)). Then, the communication device 40 receives the search packet P at the timing t54 (FIG. 10 (H)). As a result, the communication device 40 determines that the communication cutoff period T has ended, and starts the network communication COM (FIGS. 10 (G) and 10 (H)).

Then, the time detection unit 44 detects the reception time T1 (timing t51 to t54) from when the communication device 40 and the relay device 11C are electrically connected to each other until the search packet P is received, and this reception time T1 Next, the standby time T2 to be used when the communication device 40 is electrically connected to the relay device 11C is calculated based on the above. Then, the communication control unit 43 stores the information about the standby time T2 in the storage unit 42 as the standby time information INF2.

As described above, in the communication device 40, a plurality of search packets P are started to be transmitted after the waiting time T2 has elapsed since the communication device 40 and the relay device 11C are electrically connected to each other, so that a useless search is performed. Since it is not necessary to transmit the packet P, the load on the communication device 40 can be reduced.

Further, the communication device 40 detects a reception time T1 from when the communication device 40 and the relay device 11C are electrically connected to each other until the search packet P is received, and then communicates based on the reception time T1. The standby time T2 to be used when the device 40 is electrically connected to the relay device 11C is calculated. As a result, in the communication device 40, the standby time T2 corresponding to the length of the communication cutoff period T in the communication system 2 can be obtained. Therefore, as compared with the case where a fixed predetermined time is set as the standby time T2, for example. , The timing to start network communication can be set appropriately.

In particular, in the communication device 40, the standby time T2 is calculated so that the standby time T2 is shorter than the reception time T1. As a result, in the communication device 40, for example, when the network configuration is changed, the time for performing the route search operation is shortened and the length of the communication cutoff period T is shortened, as shown in FIG. , The time until the network communication is started can be shortened. That is, for example, when the fixed standby time T2 is used, for example, when the time for performing the route search operation is shortened due to a change in the network configuration, the first time after the route search operation is completed. The time until the search packet P is transmitted is wasted. On the other hand, in the communication device 40, the standby time T2 is calculated so that the standby time T2 is shorter than the reception time T1. As a result, for example, as shown in FIG. 9, a plurality of search packets P can be started to be transmitted before the route search operation is completed. As a result, in the communication device 40, the time from the end of the communication cutoff period T to the start of network communication can be shortened.

As described above, in the present embodiment, a plurality of search packets are started to be transmitted after the waiting time has elapsed since the communication device and the relay device are electrically connected to each other, so that a useless search packet is transmitted. Since it is not necessary, the load on the communication device can be reduced.

In the present embodiment, the reception time from when the communication device and the relay device are electrically connected to each other until the search packet is received is detected, and based on this reception time, the communication device is then connected to the relay device 11C. Since the standby time to be used when electrically connected is calculated, the standby time can be obtained according to the length of the communication cutoff period in the communication system, so the timing to start network communication is appropriate. Can be set to.

In the present embodiment, since the standby time is calculated so that the standby time is shorter than the reception time, the time until the network communication is started can be shortened.

Other effects are the same as in the case of the first embodiment.

[Modification 2-1]
Each modification of the first embodiment may be applied to the communication device 40 according to the first embodiment.

Although the present technology has been described above with reference to some embodiments and modifications, the present technology is not limited to these embodiments and the like, and various modifications are possible.

For example, in each of the above embodiments, the present technology is applied to an image forming apparatus, but the present technology is not limited to this, and can be applied to various network apparatus having a network interface.

1,1A, 2 ... Communication system, 11, 11A, 11B, 11C ... Relay device, 12 ... DHCP server, 13 ... Information processing device, 14, 14A, 34 ... Image forming device, 17 ... Image forming control unit, 18 ... Image forming unit, 19 ... Power supply unit, 20, 20A, 40 ... Communication device, 21 ... Communication unit, 22, 42 ... Storage unit, 23, 23A, 43 ... Communication control unit, 44 ... Time detection unit, COM ... Network communication , INF1 ... Search packet information, INF2 ... Wait time information, NET ... Network, P ... Search packet, Q ... Packet, T ... Communication cutoff period, T1 ... Reception time, T2 ... Wait time.

Claims (9)

A communication unit that can communicate with a network device via a relay device,
The communication unit transmits one or a plurality of search packets including itself as a transmission target to the relay device, receives one of the one or a plurality of search packets, and then starts communication with the network device. A communication device including a control unit that controls the operation of the communication unit. The communication device according to claim 1, wherein the control unit controls the communication unit to start transmitting the one or a plurality of search packets when the communication unit and the relay device are electrically connected to each other. .. The communication device according to claim 2, wherein the relay device transiently cuts off communication with the communication unit when the communication unit and the relay device are electrically connected to each other. 2. or claim 2, wherein the communication unit and the relay device are electrically connected to each other by supplying power to the communication unit and physically connecting the communication unit and the relay device to each other. The communication device according to 3. The control unit further controls any of claims 1 to 4 to control the communication unit to start communication with the network device when the communication unit receives a packet different from the search packet. The communication device according to paragraph 1. A storage unit that stores standby time information indicating a waiting time from when the communication unit and the relay device are electrically connected to each other until the communication unit starts transmitting one or more search packets is further provided.
The communication device according to claim 1, wherein the control unit determines a timing at which the communication unit starts transmitting the one or a plurality of search packets based on the standby time information. The control unit measures the reception time from when the communication unit and the relay device are electrically connected to each other until the reception of any one or a plurality of search packets, and is based on the reception time. The communication device according to claim 6, wherein the standby time is calculated, and the standby time information indicating the standby time is stored in the storage unit. The communication device according to claim 7, wherein the control unit calculates the standby time so that the standby time is shorter than the reception time. Sending one or more search packets that include itself as a transmission target to the relay device,
A communication method comprising receiving communication with a network device via the relay device after receiving any one or a plurality of search packets.

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