JP7218613B2 - Communication device and communication method - Google Patents

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 looped transmission line by performing a route search operation using a spanning tree protocol (eg, Patent Document 1).

JP 2004-297475 A

Communication devices are desired to start network communication in a short period of time after a route search operation based on the spanning tree protocol is performed, and it is expected that the time required to start network communication will be further shortened.

It is desirable to provide a communication device and communication method that can shorten the time to start network communication.

A communication device according to an embodiment of the present invention includes a communication section and a control section. The communication unit is configured to communicate with the network device via the relay device. After the communication unit transmits one or more search packets including itself as a transmission target to the relay device and receives one of the one or more search packets transmitted from the relay device , the network device is configured to control the operation of the communication unit to initiate communication with the

A communication method according to an embodiment of the present invention includes transmitting one or more search packets including itself as a transmission target to a relay device, and one or more search packets transmitted from the relay device. and initiating communication with the network device via the relay device after receiving the .

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

1 is a block diagram showing one configuration example of a communication system according to a first embodiment; FIG. 2 is a flowchart showing an operation example of the communication device shown in FIG. 1; 2 is a timing chart showing an operation example of the communication system shown in FIG. 1; FIG. 4 is a block diagram showing one configuration example of a communication system according to a modification of the first embodiment; FIG. 5 is a flow chart showing an operation example of the communication device shown in FIG. 4; 5 is a timing chart showing an operation example of the communication system shown in FIG. 4; FIG. 11 is a block diagram showing a configuration example of a communication system according to a second embodiment; FIG. 8 is a flow chart showing an operation example of the communication device shown in FIG. 7; 8 is a timing chart showing an operation example of the communication system shown in FIG. 7; 8 is a timing chart showing another operation example of the communication system shown in FIG. 7;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description will be given in the following order.
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 a first embodiment of the invention. The communication system 1 is configured to include redundant networks. Since the communication method according to the embodiment of the present invention is embodied by the present embodiment, it will be described together. The communication system 1 includes a plurality of relay devices 11 (three relay devices 11A, 11B, and 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 connectable to a plurality of network devices via these ports. The relay device 11 controls communication using a spanning tree protocol. Specifically, the relay device 11 detects the presence or absence of a looped transmission line by performing a route search operation using this spanning tree protocol. If there is a looped transmission line, the relay device 11 controls communication so that network packets are 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 LAN (Local Area Network) cables, for example. The relay device 11B is connected to the relay devices 11A and 11C and the information processing device 13 via LAN cables, for example. The relay device 11C is connected to the relay devices 11A and 11B and the image forming device 14 via LAN cables, for example. The relay devices 11A, 11B, and 11C include looped transmission lines as shown in FIG. That is, the relay devices 11A, 11B, and 11C form a redundant network (network NET).

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

The DHCP server 12 is configured to assign IP (Internet Protocol) addresses to network devices connected to the network NET, such as the information processing device 13 and the image forming device 14 . The DHCP server 12 is connected to the relay device 11A in this example. The DHCP server 12 communicates with a network device via the network NET, and assigns an IP address to the network device based on a 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 a user's operation, and transmits the print data to the image forming device 14 via the network NET.

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

The communication device 20 is connected to the relay device 11C and 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. 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 network NET, for example, using this IP address. . The communication device 20 has a communication section 21 , a storage section 22 and a communication control section 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, when the relay devices 11A, 11B, and 11C are performing a route search operation and communication with devices other than the relay devices 11A, 11B, and 11C is blocked, the communication unit 21 It intermittently transmits a plurality of search packets P for searching the image forming apparatus 14, which is its own apparatus. At that time, the communication unit 21 transmits the plurality of search packets P by broadcasting. In this example, this search packet P is a network packet having the format "NetBIOS Name Service". In this search packet P, the "Queries" parameter is set to "Printer-A", which is the NetBIOS name of its 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 it is not limited to this, and is used in the "WSD (Web Services on Devices)" protocol, for example. 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 nonvolatile memory. The storage unit 22 stores search packet information INF1. Search packet information INF1 includes information about search packet P transmitted by communication unit 21 .

The communication control unit 23 is configured to control communication operations of the communication device 20 . The communication control unit 23 is configured using, for example, a processor and RAM (Random Access Memory). The communication control unit 23 controls the communication unit 21 to transmit a network packet requesting IP address allocation 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 determines the assigned IP address based on this 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 receives print data transmitted from the information processing apparatus 13 by communicating with the information processing apparatus 13 using this IP address, the communication control unit 23 receives the print data. It is supplied to the image forming control section 17 .

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

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

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

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

With this configuration, in the communication system 1, the relay devices 11A, 11B, and 11C are performing route search operations, and the period during which communication with devices other than the relay devices 11A, 11B, and 11C is blocked (communication cutoff period T). , 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, the communication device 20 determines that the communication cutoff period T has ended, stops transmission of the search packet P, and stops communication with the network device. to start. As a result, the communication system 1 can shorten the time until network communication is started.

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

[Operation and action]
Next, the operation and action of the communication device 20 of this embodiment will be described.

(Outline of overall operation)
First, with reference to FIG. 1, an overview of the overall operation of the communication system 1 will be described. The relay devices 11A, 11B, and 11C relay network communications. 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 device 14 receives print data transmitted from the information processing device 13 by communicating with the information processing device 13 via the network NET. Then, the image forming device 14 forms an image on a recording medium such as paper based on this print data.

When a network device is newly electrically connected to the network NET, the relay devices 11A, 11B, and 11C detect a looped transmission line by performing a route search operation using the spanning tree protocol. During this route search operation period, 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 apparatus 14 intermittently transmits a plurality of search packets P. FIG. When the communication device 20 receives one of the plurality of search packets P, the communication device 20 stops 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 . 3 shows an operation example of the communication system 1, (A) shows the operation of the relay devices 11A, 11B, and 11C, (B) shows the operation of the communication device 20, and (C) shows the communication Transmission data of the device 20 is shown, and (D) shows reception data of the communication device 20. FIG. In the following description, a case in which the user turns on the power switch of the image forming apparatus 14 to electrically connect the relay apparatus 11C and the image forming apparatus 14 to each other will be described as an example, but the present invention is limited to this. 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 whose power switch is on to the relay device 11C using a LAN cable. The same applies to cases.

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 alternating current power supplied from the alternating current power supply AC. Start to generate power (step S101).

In the example of FIG. 3, the relay devices 11A, 11B, and 11C perform network communication relay operations during a period before timing t1 ((A) in FIG. 3). During this period, the power switch of the image forming apparatus 14 is in the OFF state, so power is not supplied to the communication apparatus 20 (FIG. 3B).

Then, at timing t1, the user turns on the power switch of the image forming apparatus 14 . As a result, 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 becomes communicable (FIG. 3(B)).

When the communication device 20 starts operating in this manner, the image forming device 14 is electrically connected to the relay device 11C. When the relay device 11C detects that it 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. 3A). As a result, the relay devices 11A, 11B, and 11C block communication with devices other than the relay devices 11A, 11B, and 11C. In this manner, a communication cut-off period T begins.

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 this 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. FIG.

In the example of FIG. 3, at timing t2, the communication device 20 transmits the first search packet P ((C) in FIG. 3). Since the relay devices 11A, 11B, and 11C have blocked communication with devices other than the relay devices 11A, 11B, and 11C, this 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 timing t3. Thus, in this example, the communication device 20 intermittently transmits a plurality of search packets P at predetermined time intervals (for example, 3-second intervals).

In step S103, when the search packet P is received ("Y" in step S103), the communication device 20 starts network communication (step S104). That is, when the search packet P is received, the communication device 20 determines that the communication interruption period T has ended, and starts network communication.

In the example of FIG. 3, at timing t4, the relay devices 11A, 11B, and 11C end the route search operation ((A) in FIG. 3). As a result, the relay devices 11A, 11B, and 11C cancel the blocking of communication with devices other than the relay devices 11A, 11B, and 11C. Thus, the communication cutoff period T ends. Then, the relay devices 11A, 11B, and 11C restart the relay operation of network communication. The relay devices 11A, 11B, and 11C control communication based on the processing result of this route search operation so that network packets are not looped and transmitted.

At subsequent timing t5, the communication device 20 transmits the search packet P (FIG. 3(C)). Since this search packet P is used to search for its own device and is broadcast, the relay device 11C transmits this search packet P to the relay devices 11A and 11B, and sends this search packet P to the communication device 20. also send to Therefore, the communication device 20 receives this search packet P at timing t6 ((D) in FIG. 3). As a result, the communication device 20 determines that the communication interruption 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 requesting IP address allocation to the DHCP server 12, and the network packet containing information about the allocated IP address transmitted from the DHCP server 12. receive. Based on this network packet, the communication control unit 23 of the communication device 20 acquires the IP address assigned by the DHCP server 12, and performs network settings based on this IP address. After that, the communication device 20 can perform network communication using this IP address. For example, the communication device 20 receives print data transmitted from the information processing device 13 by communicating with the information processing device 13 via the relay devices 11A, 11B, and 11C (network NET). Then, the image forming device 14 forms an image on a recording medium such as paper based on this print data.

This completes the flow.

As described above, in the communication device 20, when the image forming device 14 is electrically connected to the relay device 11C, transmission of a plurality of search packets P is started, and one of the plurality of search packets P is received. network communication is started when As a result, the communication device 20 can shorten the time from the end of the communication interruption period T to the start of network communication.

That is, for example, the communication device may be configured so that the communication device starts network communication when a predetermined waiting 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 ends in a short time, the communication device does not start network communication until this waiting time elapses. It may take longer time. Further, when the configuration of the network is changed, the time for performing the route search operation changes, and the length of the communication interruption period T may change. So, for example, if an administrator wants to set the wait time appropriately, in order to reduce the time it takes to start network communication, the administrator can change the wait time every time the network configuration is changed. It takes time for the administrator because it is necessary to set

On the other hand, when the communication device 20 starts transmitting a plurality of search packets P when the image forming device 14 is electrically connected to the relay device 11C, and receives one of the plurality of search packets P, to start network communication. As a result, the communication device 20 can start network communication after confirming that the communication cutoff period T has ended. can be set appropriately. Specifically, when the length of the communication cutoff period T is short, the timing of starting network communication is advanced, and when the length of the communication cutoff period T is long, the timing of starting network communication is delayed. be able to. In this manner, the communication device 20 can appropriately set the timing for starting network communication according to the length of the communication cut-off period T. The time to start network communication can be shortened. In addition, even if the network configuration is changed, the communication device 20 can appropriately set the timing for starting network communication according to the length of the communication cutoff period T. Since there is no need to set it, it is possible to reduce the work of the administrator.

[effect]
As described above, in this embodiment, when the image forming apparatus is electrically connected to the relay apparatus, it starts transmitting a plurality of search packets, and when one of the plurality of search packets is received, Since network communication is started, the timing to start network communication can be appropriately set according to the length of the communication interruption period, so the time until network communication is started can be shortened. .

[Modification 1-1]
In the above embodiment, as shown in FIG. 2, 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, even when a network packet other than the search packet P is received, network communication may be started. This modification will be described in detail below.

FIG. 4 shows a configuration example of a communication system 1A according to this modified example. The communication system 1A includes a plurality of relay devices 11 (three relay devices 11A, 11B, and 11C in this example), an information processing device 13, and an image forming device 14A. The image forming apparatus 14A has a communication device 20A. The communication device 20A has a communication control section 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-described embodiment controls communication using the IP address assigned by the DHCP server 12, but the communication control unit 23A according to this modification is configured in advance. Control is performed so that communication is performed using IP addresses. 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 interruption period T. FIG. When the communication unit 21 receives a network packet, the communication control unit 23A controls the communication unit 21 to stop transmitting the search packet P and start 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 to generate power (step S101).

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

Next, the communication device 20A confirms whether or not a 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. 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 a network packet.

In step S113, when a network packet is received ("Y" in step S103), the communication device 20A starts network communication (step S104). That is, when the communication device 20A receives a network packet, it determines that the communication interruption period T has ended, and starts network communication.

This completes the 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 timing t4, the relay devices 11A, 11B, and 11C end the route search operation, and the communication interruption period T ends (FIG. 5 (A )).

At subsequent timing t16, the communication device 20A receives packet Q ((D) in FIG. 6). Specifically, for example, immediately after timing t4, the information processing device 13 transmits this packet Q to the image forming device 14A, the network NET relays this packet Q, and communication of the image forming device 14A is performed. Device 20A receives this packet Q at 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 section 23A corresponds to a specific example of the "control section" in the present invention. The information processing device 13 corresponds to a specific example of "network device" in the present invention. Packet Q corresponds to a specific example of "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. network communication may be started after receiving two or more search packets P among the search packets P of .

[Modification 1-3]
In the above embodiment, the communication device 20 stops transmitting the search packet P when one of the plurality of transmitted search packets P is received. After receiving any one of the transmitted search packets P, some more search packets P may be transmitted.

<2. Second Embodiment>
Next, a communication system 2 according to a second embodiment will be described. In the present embodiment, after the communication device and the relay device 11C are electrically connected to each other during the communication interruption period T, the communication device starts to intermittently transmit a plurality of search packets P after the waiting time has passed. It is. In addition, the same code|symbol is attached|subjected to the substantially same component part as the communication system 1 which concerns on the said 1st Embodiment, and description is abbreviate|omitted suitably.

FIG. 7 shows a configuration example of the communication system 2. As shown in FIG. 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 section 42 and a communication control section 43 .

The storage unit 42 stores search packet information INF1 and waiting time information INF2. The waiting time information INF2 indicates the length of waiting time (waiting time T2) after the communication device 40 and the relay device 11C are electrically connected to each other and before intermittently transmitting a plurality of search packets P. Contains information.

The communication control unit 43 is configured to control communication operations of the communication device 40 . The communication control section 43 has a time detection section 44 . The time detector 44 is configured to measure 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. Based on the reception time T1, the time detection unit 44 calculates a waiting time T2 to be used when the communication device 40 is electrically connected to the relay device 11C next time. The communication control unit 43 stores information about this waiting time T2 in the storage unit 42 as waiting time information INF2.

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

Here, the communication control section 43 corresponds to a specific example of the "control section" 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 to generate power (step S101).

Next, the communication control unit 43 of the communication device 40 acquires information about the waiting time T2 based on the waiting 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 waiting time T2 has elapsed since the communication device 40 and the relay device 11C were electrically connected to each other (step S202). If the waiting time T2 has not yet passed (“N” in step S202), the communication control unit 43 repeats step S202 until the waiting time T2 has passed.

In step S202, if the waiting time T2 has elapsed ("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 this 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. FIG.

In step S103, when the search packet P is received ("Y" in step S103), the communication device 40 starts network communication (step S104). That is, when the search packet P is received, the communication device 40 determines that the communication interruption 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, based on the reception time T1 detected in step S203, the time detection unit 44 calculates a waiting time T2 to be used when the communication device 40 is electrically connected to the relay device 11C next time, and performs communication control. The unit 43 causes the storage unit 42 to store the information about the standby time T2 as the standby time information INF2 (step S204).

This completes the flow.

9A and 9B show an operation example of the communication system 2, in which (A) and (E) show the operation of the relay devices 11A, 11B and 11C, and (B) and (F) show the operation of the communication device 40. , (C) and (G) indicate transmission data of the communication device 40 and (D) and (H) indicate 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 turns on the power switch of the image forming apparatus 34. Indicates the operation when turned on.

In the examples of FIGS. 9A to 9D, the user turns on the power switch of the image forming apparatus 34 at timing t21. As a result, the 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 becomes ready for communication ((B) in FIG. 9). When the communication device 40 and the relay device 11C are thus 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 manner, a communication cut-off period T begins.

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

At timing t23, the relay devices 11A, 11B, and 11C end the route search operation ((A) in FIG. 9), and the communication cutoff period T ends. The relay devices 11A, 11B, and 11C restart the network communication relay operation. At subsequent timing t24, the communication device 40 transmits the search packet P ((C) in FIG. 9), and at timing t25, the communication device 40 receives this search packet P ((D) in FIG. 9). 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 a reception time T1 (timings 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. Based on the reception time T1, the time detection unit 44 calculates a waiting time T2 to be used when the communication device 40 is electrically connected to the relay device 11C next time. Specifically, the time detector 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 causes the storage unit 42 to store information about this waiting time T2 as waiting time information INF2.

After that, 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, at timing t31, the user turns on the power switch of the image forming apparatus 34 again. As a result, the 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 becomes ready for communication ((F) in FIG. 9). When the communication device 40 and the relay device 11C are thus electrically connected to each other, the relay devices 11A, 11B, and 11C perform a route search operation using the spanning tree protocol ((E) in FIG. 9). In this manner, a communication cut-off period T begins.

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

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

Then, the time detection unit 44 detects a reception time T1 (timings 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 detects the reception time T1. , the waiting time T2 to be used when the communication device 40 is electrically connected to the relay device 11C is calculated. Then, the communication control unit 43 causes the storage unit 42 to store information about this waiting time T2 as waiting time information INF2.

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

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

Then, the time detection unit 44 detects a reception time T1 (timings 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 detects the reception time T1. , the waiting time T2 to be used when the communication device 40 is electrically connected to the relay device 11C is calculated. Then, the communication control unit 43 causes the storage unit 42 to store information about this waiting time T2 as waiting time information INF2.

As described above, the communication device 40 starts transmitting a plurality of search packets P after the waiting time T2 has passed since the communication device 40 and the relay device 11C are electrically connected to each other. Since there is no need to transmit the packet P, the load on the communication device 40 can be reduced.

Further, 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 to when the search packet P is received. The standby time T2 to be used when the device 40 is electrically connected to the relay device 11C is calculated. As a result, the communication device 40 can obtain the waiting time T2 corresponding to the length of the communication cutoff period T in the communication system 2, so that the waiting time T2 is set to a predetermined fixed time, for example. , the timing to initiate network communication can be appropriately set.

In particular, the communication device 40 calculates the standby time T2 so that the standby time T2 is shorter than the reception time T1. As a result, in the communication device 40, for example, by changing the configuration of the network, as shown in FIG. , the time to start network communication can be shortened. That is, in the case of using the fixed waiting time T2, for example, when the time for performing the route search operation is shortened due to, for example, a change in the network configuration, after the route search operation is completed, the first , the time until the search packet P is transmitted is wasted. On the other hand, the communication device 40 calculates the standby time T2 so that the standby time T2 is shorter than the reception time T1. Thereby, for example, as shown in FIG. 9, it is possible to start transmitting a plurality of search packets P before the route search operation ends. As a result, in the communication device 40, the time from the end of the communication interruption period T to the start of network communication can be shortened.

As described above, in the present embodiment, transmission of a plurality of search packets is started after the waiting time has passed since the communication device and the relay device are electrically connected to each other. Therefore, the load on the communication device can be reduced.

In this embodiment, the reception time from when the communication device and the relay device are electrically connected to each other to when the search packet is received is detected, and based on this reception time, the communication device next contacts the relay device 11C. Since the standby time to be used when electrically connected is calculated, the standby time corresponding to the length of the communication interruption period in the communication system can be obtained. can be set to

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

Other effects are the same as in the first embodiment.

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

Although the present technology has been described above with reference to several 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 embodiments described above, 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 devices having a network interface.

Reference Signs List 1, 1A, 2... Communication system 11, 11A, 11B, 11C... Relay apparatus 12... DHCP server 13... Information processing apparatus 14, 14A, 34... Image forming apparatus 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... Waiting time information, NET... Network, P... Search packet, Q... Packet, T... Communication interruption period, T1... Receiving time, T2... Waiting time.

Claims (9)

a communication unit capable of communicating with a network device via a relay device;
The communication unit transmits one or more search packets including itself as a transmission target to the relay device, and after receiving one of the one or more search packets transmitted from the relay device , the network A communication device, comprising: a control unit for controlling operation of the communication unit to initiate communication with the device. The communication device according to claim 1, wherein said control unit controls said communication unit to start transmitting said one or more search packets when said communication unit and said 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. 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. 4. The communication device according to 3. 5. The control unit further controls 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 item 1. further comprising a storage unit that stores waiting 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 the one or more search packets;
The communication device according to claim 1, wherein the control unit determines timing at which the communication unit starts transmitting the one or more search packets based on the waiting time information. The control unit measures a reception time from when the communication unit and the relay device are electrically connected to each other to when one of the one or more search packets is received, and based on the reception time 7. The communication device according to claim 6, wherein the standby time is calculated by the controller, 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 section calculates the standby time so that the standby time is shorter than the reception time. transmitting one or more search packets including itself as a transmission target to the relay device;
initiating communication with a network device via the relay device after receiving any one of the one or more search packets transmitted from the relay device.

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