JP2012182599A - Communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology that allows a device connected to a network to obtain the IP address of a communication device even if processing to transmit the IP address is not executed.SOLUTION: If a multifunctional device 10 receives an IP address inquiry signal to inquire an IP address from a PC 300 connected to a network and determines that the IP address of the multifunctional device 10 is not registered with a DNS server 220, it transmits its IP address to the PC 300. If the multifunctional device 10 receives an IP address inquiry signal and determines that the IP address of the multifunctional device 10 is registered with the DNS server 220, it does not transmit its IP address to the PC 300.

Description

  The present specification discloses a registration server in which IP addresses of devices connected to a network are registered, and a communication apparatus connected via the network.

  Patent Document 1 discloses a printer connected to a network. When the printer receives a signal including the printer node name from the PC, the printer transmits the IP address of the printer to the PC.

JP 2007-19614 A

  A communication device connected to the network periodically acquires an IP address from another communication device on the network. The other communication devices described above must regularly transmit their IP addresses.

  It is desired to reduce the power consumption of communication devices. The present specification provides a technology that can realize power saving by reducing the opportunity for a communication apparatus to transmit an IP address.

  The technology disclosed in this specification is a communication apparatus connected via a network to a registration server in which the IP address of a device connected to the network is registered. The communication apparatus includes a first registration determination unit and an IP address transmission unit. The first registration determination unit determines whether or not the IP address of the communication device is registered in the registration server. The IP address transmission unit receives an IP address inquiry signal for inquiring about the IP address of the communication device from a transmission source device connected to the network, and the IP address of the communication device is registered in the registration server. When the determination is made, the IP address of the communication apparatus is not transmitted toward the transmission source device of the IP address inquiry signal. When the IP address inquiry signal is received and it is determined that the IP address of the communication device is not registered in the registration server, the IP address transmission unit is directed toward the transmission source device of the IP address inquiry signal. The IP address of the communication device is transmitted.

  When it is determined that the IP address of the communication device is not registered in the registration server, the communication device transmits the IP address of the communication device to the transmission source device of the IP address inquiry signal. Accordingly, the transmission source device can acquire the IP address of the communication device. On the other hand, when it is determined that the IP address of the communication apparatus is registered in the registration server, the communication apparatus does not transmit the IP address of the communication apparatus to the transmission source device of the IP address inquiry signal. This is because in such a situation, the transmission source device can obtain the IP address of the communication device from the registration server. According to this configuration, since the communication apparatus may not transmit the IP address to the transmission source device, power saving of the communication apparatus can be realized.

  The communication device may further include a storage control unit that stores predetermined information regarding whether or not the IP address of the communication device is registered in the registration server in a memory. The first registration determination unit may determine whether or not the IP address of the communication device is registered in the registration server using the predetermined information in the memory. According to this configuration, when determining whether or not the IP address of the communication device is registered in the registration server, the communication device may use the predetermined information and does not need to make an inquiry to the registration server.

  When the IP address of the registration server is designated by the user, the storage control unit may store the predetermined information indicating that the IP address of the communication device is registered in the registration server in the memory. According to this configuration, the communication apparatus can appropriately store the predetermined information in the memory.

  When the storage control unit receives a specific signal transmitted from the registration server when the IP address of the communication device is registered in the registration server, the storage control unit confirms that the IP address of the communication device is registered in the registration server. The predetermined information shown may be stored in a memory. According to this configuration, the communication apparatus can appropriately store the predetermined information in the memory.

  The communication apparatus may further include an inquiry unit that inquires of the registration server whether or not the IP address of the communication apparatus is registered in the registration server. The storage control unit receives the specific signal transmitted from the registration server in response to the inquiry, and the predetermined information indicating that the IP address of the communication device is registered in the registration server May be stored in a memory. According to this configuration, the communication device can appropriately store the predetermined information in the memory.

  The communication device further includes a confirmation unit for confirming whether or not communication with the registration server is possible after the predetermined information indicating that the IP address of the communication device is registered in the registration server is stored in the memory. You may have. When it is confirmed that the storage control unit cannot communicate with the registration server, the storage control unit may delete the predetermined information indicating that the IP address of the communication device is registered in the registration server from the memory. In a situation where the communication device cannot communicate with the registration server, there is a high possibility that other devices cannot communicate with the registration server. That is, the transmission source device cannot acquire the IP address of the communication device from the registration server. Therefore, the communication device deletes the predetermined information from the memory when the communication device cannot communicate with the registration server. Thereby, the communication apparatus can transmit the IP address of the communication apparatus toward the transmission source device of the IP address inquiry signal. According to this configuration, the transmission source device can acquire the IP address of the communication apparatus even when communication with the registration server is impossible.

  The communication apparatus may further include a signal determination unit that determines whether or not the packet is an IP address inquiry signal based on the protocol type indicated by the packet received from the network. According to this configuration, the communication apparatus can appropriately determine whether or not the received packet is an IP address inquiry signal.

  The communication apparatus may include a processor capable of transitioning between a high power consumption state with relatively high power consumption and a low power consumption state with relatively low power consumption. The processor may include a first registration determination unit and an IP address transmission unit. The processor may further include a transition control unit that shifts the processor between the high consumption state and the low consumption state. When an IP address inquiry signal is received while the processor is in a high-consumption state, the IP address transmission unit determines whether the IP address of the communication device is registered in the registration server. The IP address of the communication apparatus may be transmitted to the inquiry signal transmission source device. When the IP address inquiry signal is received while the processor is in the low consumption state and it is determined that the IP address of the communication device is not registered in the registration server, the migration control unit consumes the processor low The IP address transmission unit may transmit the IP address of the communication device to the device that is the transmission source of the inquiry signal. Transition is made when it is determined that the IP address of the communication device is registered in the registration server when the above specific signal that is an IP address inquiry signal is received while the processor is in a low consumption state. The control unit does not shift the processor from the low consumption state to the high consumption state, and the IP address transmission unit does not have to transmit the IP address of the communication apparatus toward the transmission source device of the IP address inquiry signal. According to this configuration, when the IP address inquiry signal is received while the processor is in the low consumption state, the frequency with which the processor is shifted to the high consumption state can be reduced. As a result, the power consumption of the communication device can be reduced. Further, when an IP address inquiry signal is received while the processor is in a high consumption state, the communication device can determine whether the IP address of the communication device is registered in the registration server. To the source device. Therefore, the communication apparatus can appropriately supply the IP address of the communication apparatus to the transmission source device.

  The communication apparatus may further include a first signal transmission unit, a second signal transmission unit, and a second registration determination unit. The first signal transmission unit may transmit a first acquisition signal for acquiring an IP address of a specific device connected to the network from the registration server to the registration server. The second signal transmission unit may transmit a second acquisition signal for acquiring the IP address of the specific device from the specific device by at least one of broadcast and multicast. The second registration determination unit may determine whether the IP address of the specific device is registered in the registration server when the IP address of the specific device is to be acquired. . When it is determined that the IP address of the specific device is not registered in the registration server, the second signal transmission unit may transmit the second acquisition signal by at least one of broadcast and multicast. When it is determined that the IP address of the specific device is registered in the registration server, the first signal transmission unit transmits the first acquisition signal to the registration server, and the second signal transmission unit The second acquisition signal may not be transmitted. According to this configuration, the communication apparatus transmits the first acquisition signal to the registration server when it is determined that the IP address of the specific device is registered in the registration server. Do not send. When the IP address of the specific device is registered in the registration server, the communication apparatus can acquire the IP address from the registration server without acquiring the IP address from the specific device. . In this case, since the second acquisition signal is not transmitted, power saving of the communication device can be realized.

  A control method, a computer program, and a storage medium storing the computer program for realizing the communication apparatus are also novel and useful. A system including the communication device and the registration server is also new and useful.

The structure of a network system is shown. The flowchart of the process which main CPU performs is shown. 3 shows a flowchart of an IP address setting process executed by the main CPU. The flowchart of the registered flag change process which main CPU performs is shown. The flowchart of the process which sub CPU performs is shown. 6 shows a flowchart of name resolution processing executed by the main and sub CPUs. The sequence diagram of the process which each apparatus performs is shown. FIG. 6 shows a sequence diagram when the multi-function device 10 executes name resolution.

  As shown in FIG. 1, the network system 2 includes a PC 100, a multi-function device (that is, a peripheral device of the PC 100) 10, and a server 200. The devices 10, 100, and 200 can communicate with each other via the LAN 4.

(Configuration of multi-function device 10)
As shown in FIG. 1, the multi-function device 10 includes an application specific integrated circuit (ASIC) 12, a flash memory 70, an SDRAM 80, a network interface 90, a printer engine 92, and a display panel 94.

  The ASIC 12 includes a main CPU 20, a main clock circuit 36, a sub CPU 40, a sub clock circuit 42, an SRAM 60, an SDRAM control circuit 64, and a MAC controller 66.

  The main CPU 20 executes various processes according to the program 82 stored in the SDRAM 80. Thereby, the functions of the IP address transmission unit 22, the storage control unit 24, the inquiry unit 26, the confirmation unit 28, the first signal transmission unit 30, the second signal transmission unit 32, and the second registration determination unit 34 Is realized. The main clock circuit 36 supplies a clock signal to the main CPU 20. While the clock signal is supplied from the main clock circuit 36 to the main CPU 20, the main CPU 20 is in a non-sleep state. While the clock signal is not supplied to the main CPU 20, the main CPU 20 is in a sleep state. The sleep state of the main CPU 20 is a state in which power consumption is lower than the non-sleep state of the main CPU 20. The main clock circuit 36 can control the supply and stop of the clock signal to the main CPU 20 by the sub CPU 40.

  The sub CPU 40 executes various processes according to the program 62 stored in the SRAM 60. Accordingly, the first registration determination unit 44, the storage control unit 46, the second registration determination unit 48, the signal determination unit 50, the transition control unit 52, the first signal transmission unit 54, the second signal transmission unit 56, And the function of the confirmation part 58 is implement | achieved. The sub clock circuit 42 supplies a clock signal to the sub CPU 40. The frequency of the clock signal of the sub clock circuit 42 is lower than the frequency of the clock signal of the main clock circuit 36. Therefore, the power consumption for driving the sub CPU 40 is lower than the power consumption for driving the main CPU 20. Furthermore, the processing speed of the main CPU 20 is faster than the processing speed of the sub CPU 40. The sub clock circuit 42 supplies a clock signal to the sub CPU 40 when the power of the multi-function device 10 is turned on, and stops the clock signal when the power of the multi-function device 10 is turned off. That is, the sub CPU 40 is maintained in a state where the clock signal is supplied (non-sleep state) while the power of the multi-function device 10 is turned on. In a modification, the sub CPU 40 may be in a sleep state while the main CPU 20 is in a non-sleep state.

  The SRAM 60 can be accessed from the CPUs 20 and 40. When the power of the multi-function device 10 is turned on, the main CPU 20 expands the compressed program 72 in the flash memory 70 and stores the expanded program 62 in the SRAM 60.

  The SDRAM control circuit 64 starts or stops the supply of the clock signal to the SDRAM 80 in accordance with an instruction from the sub CPU 40, and a normal operation mode with relatively high power consumption, a self-refresh mode with relatively low power consumption, The state of the SDRAM 80 is shifted between.

  The MAC controller 66 is connected to the network interface 90. When a packet is received by the network interface 90 via the LAN 4 or the like, the MAC controller 66 supplies a packet interrupt request signal to an interrupt controller (not shown) of the main CPU 20 or the sub CPU 40.

  The flash memory 70 is provided outside the ASIC 12. The flash memory 70 can be accessed from the CPUs 20 and 40. The flash memory 70 stores a program 72 in which the programs 62 and 82 executed by the CPUs 20 and 40 are compressed.

  The SDRAM 80 is accessible from the main CPU 20. The SDRAM 80 has a larger total memory capacity than the SRAM 60, and the CPU 20 and 40 can access (read and write) at a high speed. For this reason, the power consumption of the SDRAM 80 is higher than the power consumption of the SRAM 60. The SDRAM 80 is controlled by the SDRAM control circuit 64, and the state shifts between the normal operation mode and the self-refresh mode.

  The printer engine 92 includes a printing mechanism such as an inkjet method or a laser method. The printer engine 92 executes printing in accordance with an instruction from the main CPU 20. The display panel 94 displays information in accordance with instructions from the main CPU 20.

(Multifunction device status transition)
The state of the multi-function device 10 is changed between the ready state and the sleep state. When the power of the multi-function device 10 is turned on, the multi-function device 10 enters a ready state.

  In the ready state, the two CPUs 20 and 40 are in a non-sleep state (a state where a clock is supplied). In the ready state, the two RAMs 60 and 80 are in the normal operation mode. In the ready state, the main CPU 20 can execute normal processing. The normal processing includes printing processing by the printer engine 92 according to the print instruction packet, display processing according to the user's operation on the display panel 94, and the like.

  The multi-function device 10 shifts from the ready state to the sleep state when the sub CPU 40 executes a transition process of S74 and S76 in FIG. In the sleep state, the main CPU 20 is in the sleep state, the sub CPU 40 is in the non-sleep state, the SRAM 60 is in the normal operation mode, and the SDRAM 80 is in the self-refresh mode. When the multi-function device 10 is in the sleep state and the main CPU 20 is to execute the normal processing (printing process, display processing, etc.), the multi-function device 10 shifts to the ready state.

(Configuration of server 200)
The server 200 realizes functions of a DHCP (Dynamic Host Configuration Protocol) server 210 and a DNS (Domain Name System) server 220. That is, in the present embodiment, the DHCP server 210 and the DNS server 220 are integrally configured. In the modification, the DHCP server 210 and the DNS server 220 may be separate.

  The DHCP server 210 assigns an IP address and a subnet mask to the above device in response to a request from a device (for example, the multi-function device 10 or the PC 100) connected to the LAN 4. For example, the multi-function device 10 transmits an allocation request packet for requesting IP address allocation to the DHCP server 210. Note that the allocation request packet includes the node name of the multi-function device 10 (ie, “MFP 10”). The DHCP server 210 assigns (transmits) an IP address selected from a predetermined IP address range and a predetermined subnet mask to the multi-function device 10. Thereby, the multi-function device 10 can acquire the IP address and the subnet mask from the DHCP server 210 and store them as setting values of the multi-function device 10. Similarly, the PC 100 can acquire the IP address and subnet mask from the DHCP server 210 and store them as setting values of the PC 100.

(Configuration of DNS server 220)
The DNS server 220 stores an IP address table 222. The IP address table 222 includes, for each of a plurality of devices (for example, the multi-function device 10 and the PC 100) connected to the LAN 4, the node names (for example, “MFP 10” and “PC 100”) of the device, Combinations with IP addresses can be stored. That is, the DNS server 220 can register the combination of the node name and the IP address in the IP address table 222. In a modification, the registration server that registers the combination of the node name and the IP address may be a WINS (Windows (registered trademark) Internet Name Service) server.

(Registration method of IP address to DNS server 220)
When the DHCP server 210 assigns an IP address to a device connected to the LAN 4 (for example, the multi-function device 10 or the PC 100), the node name (for example, “MFP 10” or “PC 100”) included in the assignment request packet. The combination of the assigned IP address is supplied to the DNS server 220. The DNS server 220 registers the combination of the node name and the IP address acquired from the DHCP server 210 in the IP address table 222.

  When the DNS server 220 further receives an IP address registration request from a device (for example, the multi-function device 10 or the PC 100) connected to the LAN 4, the DNS server 220 displays the combination of the node name and the IP address in the IP address table. 222 is registered. For example, the PC 100 transmits a registration request packet for requesting registration of the IP address of the PC 100 itself to the DNS server 220. The registration request packet includes a combination of the node name “PC100” of the PC 100 itself and the IP address of the PC 100 itself. Further, the PC 100 can transmit a registration request packet for requesting registration of an IP address of another device (for example, the multi-function device 10) connected to the LAN 4 to the DNS server 220. The registration request packet includes a combination of the node name “MFC10” of the multi-function device 10 and the IP address of the multi-function device 10.

(Configuration of PC100)
The PC 100 can transmit (unicast) an IP address inquiry packet for inquiring an IP address of another device (for example, the multi-function device 10) connected to the LAN 4 to the DNS server 220. When the DNS server 220 receives the IP address inquiry packet, the DNS server 220 specifies an IP address combined with the node name (for example, the node name of the multi-function device 10) included in the IP address inquiry packet from the IP address table 222. To the PC 100. The PC 100 can know the IP address of another device (for example, the multi-function device 10) by receiving the IP address from the DNS server 220. Hereinafter, a method for acquiring an IP address by transmitting an IP address inquiry packet to the DNS server 220 is referred to as “static name resolution”, and an IP address inquiry packet is referred to as a “name resolution packet”.

  The PC 100 can also transmit the name resolution packet to the LAN 4 by broadcast or multicast. The protocol of the name resolution packet is NetBIOS (Network Basic Input Output System) or LLMNR (Link-local Multicast Name Resolution). In this case, each device connected to the LAN 4 receives the name resolution packet. Each device transmits a response including its own IP address to the PC 100 when its own node name is included in the name resolution packet. The PC 100 can acquire the IP address of a device (for example, the multi-function device 10) connected to the LAN 4 by receiving the response of the name resolution packet. Hereinafter, a technique for acquiring an IP address from a device connected to the LAN 4 by transmitting a name resolution packet by broadcast or the like is referred to as “dynamic name resolution”.

  The PC 100 can simultaneously perform both name resolution and static name resolution. For example, the PC 100 obtains the IP address of the multi-function device 10 from both the DNS server 220 and the multi-function device 10 as a result of executing both of the above name resolutions in order to obtain the IP address of the multi-function device 10. If it can, the IP address acquired earlier is used as the IP address of the multi-function device 10.

(Processing executed by the main CPU 20)
Next, the contents of processing executed by the main CPU 20 in the non-sleep state (that is, the multi-function device 10 is in the ready state) will be described. The main CPU 20 in the sleep state cannot execute processing because the clock supply is stopped. The process of FIG. 2 is repeatedly executed while the main CPU 20 is in the non-sleep state.

  In S <b> 12, the main CPU 20 monitors reception of a packet via the LAN 4. Specifically, when a packet is received by the network interface 90, the MAC controller 66 supplies a packet interrupt request signal to the main CPU 20. When the main CPU 20 acquires the packet interrupt request signal, the main CPU 20 moves the received packet from the network interface 90 to the SDRAM 80.

  In S14, the main CPU 20 analyzes the packet moved to the SDRAM 80, and determines whether or not the protocol type indicated by the received packet is a name resolution protocol. Specifically, when the destination port number included in the header of the received packet is a NetBIOS or LLMNR port number (for example, the port numbers are 137 and 5355), the main CPU 20 determines YES in S14. When the destination port number included in the header of the received packet is other than the port number of the NetBIOS or LLMNR port number, the main CPU 20 determines NO in S14.

  If YES in S14, in S16, the IP address transmission unit 22 transmits the IP address of the multi-function device 10 to the source device (for example, PC 100) of the name resolution packet as a response to the name resolution packet, and then proceeds to S20. move on. On the other hand, in the case of NO in S14, in S18, the main CPU 20 executes processing according to the packet received in S12 (for example, the above-described normal processing (print processing according to the print instruction packet, etc.)), and S20 Proceed to

  In S20, the main CPU 20 determines whether or not the sleep transition condition is satisfied. Specifically, the main CPU 20 determines, for example, (1) whether the multi-function device 10 is transmitting a packet to the outside, (2) whether an unprocessed packet is stored in the SDRAM 80, (3 ) Whether there is a device (for example, PC 100) connected to the multi-function device 10 via TCP, (4) Whether the multi-function device 10 is executing processing for startup or shutdown, (5) Network It is judged about a plurality of conditions including whether or not the load is high.

  For example, when the main CPU 20 returns a response to the packet from the PC 100 or the like, YES is determined in (1) above. For example, if the multi-function device 10 has a Web server function and the PC 100 is in TCP connection with the Web server of the multi-function device 10, it is determined YES in (3) above. For example, when the number of packets received in a predetermined period immediately before executing the process of S20 exceeds a predetermined number, the multi-function device 10 is highly likely to receive a packet to be processed. It is determined as YES in (5) above. When any of the above conditions (1) to (5) is determined negatively, the sleep transition condition is satisfied. In this case, the main CPU 20 determines YES in S20.

  If it is determined that the sleep transition condition is not satisfied (NO in S20), the process returns to S12. On the other hand, if it is determined that the sleep transition condition is satisfied (YES in S20), the main CPU 20 moves the proxy response information from the SDRAM 80 to the SRAM 60 in S22. The proxy response information is information (for example, an ink cartridge of the printer engine 92) for the sub CPU 40 to execute processing according to a packet received while the multi-function device 10 is in the sleep state (that is, the main CPU 20 is in the sleep state). Information indicating the status of the multi-function device 10, such as the remaining amount. The main CPU 20 further moves a name resolution unnecessary flag and a registered flag, which will be described later, from the SDRAM 80 to the SRAM 60.

  In S24, the main CPU 20 switches the RAM for storing packets received via the LAN 4 from the SDRAM 80 to the SRAM 60. Subsequently, in S26, the main CPU 20 masks (prohibits) interrupt requests from other than the sub CPU 40. Next, in S <b> 28, the main CPU 20 supplies the sub CPU 40 with a start interrupt request signal for causing the sub CPU 40 to start processing. In S30, the main CPU 20 executes a WAIT command. When the WAIT instruction is executed, the main CPU 20 enters an execution stop state in which it waits until an interrupt request signal is supplied.

  In S32, when the interrupt request signal is supplied from the sub CPU 40 in S32 (see S94 in FIG. 5 described later), the main CPU 20 cancels the WAIT command and proceeds to S34. In S <b> 34, the main CPU 20 moves unprocessed packets stored in the SRAM 60 to the SDRAM 80. In S <b> 36, the main CPU 20 moves the information stored in the SRAM 60 (including the status information of the multi-function device 10, the name resolution unnecessary flag and the registered flag) to the SDRAM 80. Next, in S38, the main CPU 20 cancels the mask executed in S26 and returns to S12.

(IP address setting process executed by the main CPU)
Next, the contents of the IP address setting process of FIG. 3 executed by the main CPU 20 will be described. The IP address of the multi-function device 10 is acquired from the DHCP server 210 or is input to the multi-function device 10 depending on whether the IP address is input by an operation (input operation) of the display panel 94 by the user. Is set. Whether the user operates the display panel 94 to input an IP address (i.e., setting of the STATIC IP address) or to obtain an IP address from the DHCP server 210 (i.e., setting of the DHCP IP address); Can be selected.

  When the current setting of the multi-function device 10 is a DHCP IP address setting, the main CPU 20 periodically acquires an IP address from the DHCP server 210 and updates the IP address of the multi-function device 10. On the other hand, when the current setting of the multi-function device 10 is the setting of the IP address of the STATIC, the main CPU 20 is input by the previous input operation until the input operation of the IP address and the subnet mask by the user is executed again. The IP address and subnet mask are not changed.

  When the current setting of the multi-function device 10 is the setting of the STATIC IP address, in S42, the main CPU 20 monitors whether the user performs an input operation of the IP address and the subnet mask. On the other hand, if the current setting of the multi-function device 10 is a DHCP IP address setting, the main CPU 20 monitors the arrival of the timing for acquiring the IP address and subnet mask from the DHCP server 210 in S42. Specifically, the main CPU 20 monitors whether the current date and time has passed the expiration date of the IP address acquired from the DHCP server 210 last time.

  When an IP address input operation is performed by the user, the main CPU 20 stores the input IP address and subnet mask in the SDRAM 80 as the IP address and subnet mask of the multi-function device 10. Next, in S44, the main CPU 20 causes the display panel 94 to display a screen for designating the IP address of the DNS server 220. The main CPU 20 monitors whether an address specifying operation for specifying the IP address of the DNS server 220 is executed by the user.

  The screen displayed on the display panel 94 in S44 is one of the following two types of screens. Which of the two types of screen is displayed is determined depending on whether or not the IP address of the DNS server 220 is currently stored in the SDRAM 80.

  When the IP address of the DNS server 220 is currently stored in the SDRAM 80 (for example, when the IP address of the DNS server 220 is specified in the past processing of S44), the main CPU 20 is currently stored in the SDRAM 80 in S44. A screen including the IP address of the existing DNS server 220 and an “OK” button is displayed on the display panel 94. The user can confirm the IP address of the DNS server 220 displayed on the display panel 94 and operate the “OK” button on the display panel 94. On the other hand, if the IP address of the DNS server 220 is not currently stored in the SDRAM 80, the main CPU 20 causes the display panel 94 to display a screen including an input box for inputting the IP address of the DNS server 220 in S44. Can do. The user can execute an operation of inputting the IP address of the DNS server 220 by operating the display panel 94.

  When an IP address designation operation (“OK” button operation or DNS server 220 IP address input operation) is executed, the main CPU 20 registers the IP address of the multi-function device 10 in the DNS server 220. (YES in S44), the process proceeds to S54. In S54, the storage control unit 24 of the main CPU 20 sets the name resolution unnecessary flag in the SDRAM 80 to “1”. When S54 ends, the IP address setting process ends.

  On the other hand, when no operation is performed by the user even after a predetermined period (for example, 5 minutes) has elapsed since the screen is displayed on the display panel 94 in S44, or when the cancel operation is executed by the user, the main CPU 20 If it is determined that the IP address of the multi-function device 10 is not registered in the DNS server 220 (NO in S44), the process proceeds to S46. In S46, the storage control unit 24 of the main CPU 20 sets the name resolution unnecessary flag in the SDRAM 80 to “0” and ends the IP address setting process.

  If it is determined in S42 that it is time to acquire an address from the DHCP server 210, the main CPU 20 acquires an IP address from the DHCP server 210 in S48. That is, the main CPU 20 transmits an allocation request packet including the node name of the multi-function device 10 (that is, “MFP 10”) to the DHCP server 210. The DHCP server 210 assigns (transmits) an IP address and a predetermined subnet mask to the multi-function device 10. As a result, the main CPU 20 acquires the IP address and subnet mask from the DHCP server 210. The main CPU 20 stores the acquired IP address and subnet mask in the SDRAM 80 as the IP address and subnet mask of the multi-function device 10.

  As described above, when the DHCP server 210 assigns an IP address to the multi-function device 10, the DHCP server 210 causes the DNS server 220 to register the assigned IP address and the node name of the multi-function device 10 in the IP address table 222. Request.

  Next, in S50, the inquiry unit 26 inquires of the DNS server 220 whether or not the IP address of the multi-function device 10 has been registered. Specifically, the inquiry unit 26 transmits a predetermined inquiry signal to the DNS server 220. In S52, the inquiry unit 26 monitors that registration completion information is received from the DNS server 220 in accordance with the inquiry signal transmitted in S50. The registration completion information is information indicating that the IP address of the multi-function device 10 is registered in the DNS server 220.

  When registration completion information is received in S52, the process proceeds to S54. As described above, in S54, the storage control unit 24 of the main CPU 20 sets the name resolution unnecessary flag stored in the SDRAM 80 to “1”, and ends the IP address setting process. In addition, also when it is YES in S44, it progresses to S54. This is because when the IP address of the DNS server 220 is designated by the user in S44, it is assumed that the IP address of the multi-function device 10 is already registered in the DNS server 220 by the user.

  In the modified example, in the case of YES in S44 (that is, when the IP address of the DNS server 220 is designated), the inquiry unit 26 determines whether or not the IP address of the multi-function device 10 has been registered. 220 may be queried. The storage control unit 24 of the main CPU 20 executes the process of S54 when registration completion information is received from the DNS server 220, and executes the process of S46 when registration completion information is not received from the DNS server 220. May be. Alternatively, in another modified example, when YES is obtained in S44, the main CPU 20 may transmit a registration request packet including the IP address and node name of the multi-function device 10 to the DNS server 220. Thereafter, the storage control unit 24 of the main CPU 20 may execute the process of S54.

  In another modification, the following processing may be executed instead of the processing of S50 and S52. As described above, in S42, it is determined that it is time to acquire an IP address from the DHCP server 210 (YES in S42), and in S48, the main CPU 20 transmits an allocation request packet to the DHCP server 210.

  In this modification, when the DHCP server 210 receives the allocation request packet, before assigning the IP address to the multi-function device 10, the DHCP server 210 assigns the IP address to be assigned to the multi-function device 10 in the subsequent processing and the received node name. The DNS server 220 is requested (sent) to be registered in the IP address table 222. In response to the request, the DNS server 220 registers the IP address and node name in the IP address table 222 and transmits registration completion information to the DHCP server 210.

  When the DHCP server 210 receives the registration completion information, the DHCP server 210 assigns (transmits) the IP address registered in the multi-function device 10 and a predetermined subnet mask to the multi-function device 10. As a result, the main CPU 20 of the multi-function device 10 acquires the IP address and subnet mask from the DHCP server 210. The main CPU 20 stores the acquired IP address and subnet mask in the SDRAM 80 as the IP address and subnet mask of the multi-function device 10. In the present modification, when the main CPU 20 transmits an allocation request packet to the DHCP server 210 in S42 and acquires the IP address and subnet mask from the DHCP server 210, the process proceeds to S54. With this configuration, the multi-function device 10 does not need to make an inquiry to the DNS server 220 as to whether or not the IP address of the multi-function device 10 has been registered.

(Registered flag change process executed by the main CPU)
Next, the contents of the registered flag changing process of FIG. 4 executed by the main CPU 20 will be described. For example, when the user is an administrator of the LAN 4 or when the user confirms the IP address table 222 of the DNS server 220, the user is connected to the LAN 4 other than the multi-function device 10 (for example, It is possible to know whether the IP address of the PC 100 or the like is registered in the DNS server 220.

  The user can perform a registered operation indicating that the IP address of another device has been registered in the DNS server 220 by operating the display panel 94. On the other hand, by operating the display panel 94, the user can execute an incomplete registration operation indicating that the IP address of the other device is not registered in the DNS server 220.

  The registered flag changing process in FIG. 4 is repeatedly executed while the main CPU 20 is in the non-sleep state. In S62, the main CPU 20 monitors execution of the registered operation. When the registered operation is executed (YES in S62), in S64, the main CPU 20 sets the registered flag stored in the SDRAM 80 to “1”.

  In S66, the main CPU 20 monitors whether a registration incomplete operation is executed by the user. When the registration incomplete operation is executed by the user (YES in S66), the main CPU 20 sets the registered flag stored in the SDRAM 80 to “0” in S68.

(Processing executed by the sub CPU 40)
Next, the contents of the process of FIG. 5 executed by the sub CPU will be described. When the power of the multi-function device 10 is turned on, the sub CPU 40 executes a WAIT command and waits until an interrupt request signal is supplied (S72). As described above, the main CPU 20 supplies the start interrupt request signal to the sub CPU 40 in S28 of FIG. In this case, YES is determined in S72.

  If YES in S72, the transition control unit 52 instructs the main clock circuit 36 to stop the clock supply in S74. As a result, the main CPU 20 shifts from the non-sleep state to the sleep state. Subsequently, the transition control unit 52 shifts the SDRAM 80 from the normal operation mode to the self-refresh mode (S76). As a result, the multi-function device 10 enters a sleep state. While the SDRAM 80 is in the self-refresh mode, packets received by the multi-function device 10 cannot be stored in the SDRAM 80.

  In S78, the sub CPU 40 monitors reception of a packet. Specifically, when a packet is received by the network interface 90, the MAC controller 72 supplies a packet interrupt request signal to the sub CPU 40. In S78, when the packet interrupt request signal is supplied from the MAC controller 72 (YES in S78), the sub CPU 40 moves the received packet from the network interface 90 to the SRAM 60.

  Next, in S80, the signal determination unit 50 determines whether the packet received in S78 is a name resolution packet (that is, the protocol type indicated by the packet is a name resolution protocol (NetBIOS, LLMNR)). The processing is determined by using the destination port number included in the header of the packet received in S78, similarly to the processing in S14 of Fig. 2. According to this configuration, the signal determination unit 50 determines the received packet. The signal determination unit 50 can determine whether or not the received packet name resolution packet is received without performing detailed analysis, and the destination port number of the received packet is the port number of NetBIOS or LLMNR. In this case, YES is determined in S80, and if it is a port number other than that, NO is determined in S80.

  In the case of NO in S80, the sub CPU 40 determines whether or not the response processing according to the packet received in S78 can be executed on behalf of the main CPU 20. Specifically, the sub CPU 40 uses the proxy response information stored in the SRAM 60 to determine whether the response process according to the packet received in S78 can be executed. The response processing that can be executed on behalf of the sub CPU 40 includes, for example, a response to PING, a response to an ARP (Address Resolution Protocol) packet, and the like.

  When the sub CPU 40 is able to respond on behalf (YES in S82), the sub CPU 40 executes a response process according to the packet received in S78 (S84), and returns to S78. On the other hand, if the sub CPU 40 is unable to respond on behalf (NO in S82), the process proceeds to S90.

  On the other hand, in the case of YES in S80, in S86, the first registration determination unit 44 determines whether or not the name resolution unnecessary flag stored in the SRAM 60 is set to “1”. That is, the first registration determination unit 44 determines whether or not the IP address of the multi-function device 10 is registered in the DNS server 220. If YES in S86, that is, if the IP address of the multi-function device 10 is registered in the DNS server 220, the transmission source device (for example, PC 100) of the packet received in S78 performs static name resolution. By doing so, the IP address of the multi-function device 10 can be acquired from the DNS server 220. Therefore, in S88, the multi-function device 10 discards the name resolution packet without responding to the name resolution packet received in S78, and returns to S78.

  On the other hand, if NO in S86, the process proceeds to S90. If NO in S86, that is, if the IP address of the multi-function device 10 is not registered in the DNS server 220, the source device (for example, PC 100) of the packet received in S78 performs static name resolution. By doing so, the IP address of the multi-function device 10 cannot be acquired from the DNS server 220. For this reason, the multi-function device 10 executes a process for responding to the name resolution packet received in S78 (see S16 in FIG. 2).

  In S90, the transition control unit 52 shifts the SDRAM 80 from the self-refresh mode to the normal operation mode. Note that the migration control unit 52 further switches the RAM that stores a packet received from an external device (for example, the PC 100) from the SRAM 60 to the SDRAM 80. Further, the migration control unit 52 moves the information (including the name resolution unnecessary flag and the registered flag) stored in the SRAM 60 to the SDRAM 80. Next, in S92, the transition control unit 52 instructs the main clock circuit 36 to start the clock supply to the main CPU 20. As a result, the clock is supplied to the main CPU 20, and the main CPU 20 shifts from the sleep state to the non-sleep state. In S94, the transition control unit 52 supplies a start interrupt request signal to the main CPU 20, and returns to S72.

  As a result, the WAIT instruction in S32 of FIG. 2 is canceled, and the main CPU 20 executes the processing of FIG. Thereby, the main CPU 20 determines YES in S12 and S14 for the name resolution packet stored in the SDRAM 80 (name resolution packet received in S78 of FIG. 5). As a result, the IP address transmission unit 22 of the main CPU 20 transmits the IP address of the multi-function device 10 to the transmission source device (for example, the PC 100) of the name resolution packet received in S78.

(Name resolution process executed by main CPU and sub CPU)
Next, the contents of the name resolution process of FIG. 6 executed by the main CPU 20 and the sub CPU 40 will be described. When the main CPU 20 is in the non-sleep state (that is, the multi-function device 10 is in the ready state), the main CPU 20 periodically executes the name resolution process of FIG. When the main CPU 20 is in the sleep state (that is, the multi-function device 10 is in the sleep state), the sub CPU 40 periodically executes the name resolution process of FIG. In the following, the name resolution process will be described taking the case where the main CPU 20 executes the process as an example. That is, in the following, each unit (the storage control unit 24, the confirmation unit 28, the first signal transmission unit 30, the second signal transmission unit 32, and the second registration determination unit 34) realized by the main CPU 20 performs each process. The state of execution will be described. When the main CPU 20 is in the sleep state, each unit realized by the sub CPU 40 (storage control unit 46, confirmation unit 58, first signal transmission unit 54, second signal transmission unit). 56, the second registration determination unit 48) similarly executes each processing.

  In S102, the first signal transmission unit 30 of the main CPU 20 transmits (unicasts) a name resolution packet for inquiring an IP address of a specific device (for example, the PC 100) connected to the LAN 4 to the DNS server 220. (Ie perform static name resolution). Note that the name resolution packet includes the node name of the specific device.

  The second registration determination unit 34 of the main CPU 20 determines whether or not the registered flag stored in the SDRAM 80 is “1” in S104 simultaneously with the process of S102. The case where the registered flag is “1” is a case where the IP address of the specific device is registered in the DNS server 220. In this case, that is, if YES in S104, the process proceeds to S108.

  On the other hand, when the registered flag is “0”, that is, when the IP address of the specific device is not registered in the DNS server 220 (NO in S104), in S106, the second CPU 20 The signal transmission unit 32 broadcasts or multicasts the name resolution packet.

  The confirmation unit 28 of the main CPU 20 monitors whether a response to the name resolution packet is received from the DNS server 220 and at least one of the specific devices. When the IP address is received from the DNS server 220 (YES in S108), the confirmation unit 28 of the main CPU 20 stores the IP address in the SDRAM 80 and ends the name resolution process. When the information indicating that the IP address of the specific device is not registered is received from the DNS server 220 (YES in S108), the confirmation unit 28 of the main CPU 20 ends the name resolution process. When an IP address is received as a response to the broadcast or multicast from the specific device, the confirmation unit 28 of the main CPU 20 stores the IP address in the SDRAM 80.

  On the other hand, when the confirmation unit 28 of the main CPU 20 does not receive a response (information indicating that the IP address or IP address is not registered) from the DNS server 220 (NO in S108), the process proceeds to S110. The case where a response is not received from the DNS server 220 is a case where communication with the DNS server 220 via the LAN 4 is impossible. For example, when the DNS server 220 is down, it is not possible to communicate with the DNS server 220 via the LAN 4. In this case, it is expected that devices other than the multi-function device 10 (for example, the PC 100) cannot communicate with the DNS server 220 and acquire the IP address of the multi-function device 10 from the DNS server 220.

  The storage control unit 24 of the main CPU 20 determines whether or not the name resolution unnecessary flag stored in the SDRAM 80 is “1” (S110). If the name resolution unnecessary flag is “1” (YES in S110). ), The name resolution unnecessary flag is set to “0” (S112), and the name resolution processing is terminated. In this configuration, the multi-function device 10 transmits its IP address to the name resolution packet even in the sleep state (the main CPU 20 is in the sleep state). As a result, the source device (for example, PC 100) of the name resolution packet can acquire the IP address of the multi-function device 10 even in a situation where it cannot communicate with the DNS server 220.

(Operation of each device (Fig. 7))
When the multi-function device 10 is in the ready state, the multi-function device 10 periodically requests the DHCP server 210 to assign an IP address. The DHCP server 210 assigns (transmits) an IP address to the multi-function device 10 in response to a request for an IP address from the multi-function device 10. The multi-function device 10 stores the IP address received from the DHCP server 210 in the SDRAM 80. The DHCP server 210 supplies the assigned IP address and the node name of the multi-function device 10 to the DNS server 220. The DNS server 220 registers the combination of the IP address and node name of the multi-function device 10 in the IP address table 222.

  When the multi-function device 10 receives the IP address from the DHCP server 210, the multi-function device 10 inquires of the DNS server 220 whether or not the IP address of the multi-function device 10 is registered. The DS server 220 transmits registration completion information to the multi-function device 10 on the condition that the combination of the IP address and the node name of the multi-function device 10 is registered in the IP address table 222. When acquiring the registration completion information, the multi-function device 10 sets the name resolution unnecessary flag to “1”. According to this configuration, the multi-function device 10 can determine whether or not its own IP address is registered in the DNS server 220 by checking the name resolution unnecessary flag.

  When the multi-function device 10 is in the ready state, the dynamic name of the PC 100 regardless of the value of the name resolution unnecessary flag, that is, whether or not its own IP address is registered in the DNS server 220. In response to the resolution packet (IP address inquiry), it transmits its own IP address. As a result, the PC 100 can acquire the IP address of the multi-function device 10 from the multi-function device 10.

  On the other hand, when the multi-function device 10 is in the sleep state, while its name resolution unnecessary flag is “1”, its own IP address is transmitted to the dynamic name resolution packet (IP address inquiry) of the PC 100. do not do. This is because the PC 100 can obtain the IP address of the multi-function device 10 from the DNS server 220 by static name resolution. According to this configuration, the frequency with which the multi-function device 10 is shifted from the sleep state to the ready state (that is, the main CPU 20 is shifted from the sleep state to the non-sleep state) is reduced. For this reason, the power consumption of the multi-function device 10 can be reduced.

  The multi-function device 10 has a case where the name resolution unnecessary flag is “0”, that is, when the IP address of the multi-function device 10 is not registered in the DNS server 220 and when the DNS server 220 cannot communicate with the PC 100. When the dynamic name resolution packet of the PC 100 is received, the sleep state is shifted to the ready state, and its own IP address is transmitted. According to this configuration, the PC 100 can acquire the IP address of the multi-function device 10 from the multi-function device 10 in a situation where the IP address of the multi-function device 10 cannot be acquired from the DNS server 220.

(Processing of the multi-function device 10 when the multi-function device 10 executes name resolution)
As shown in FIG. 8, when the registered flag is set to “0”, that is, when it is determined that the IP address of the PC 100 is not registered in the DNS server 220, the multi-function device 10 The machine 10 inquires of both the DNS server 220 and the PC 100 about the IP address of the PC 100 (that is, performs dynamic name resolution and static name resolution). The multi-function device 10 can acquire the IP address of the PC 100 from the PC 100. On the other hand, the multi-function device 10 cannot acquire the IP address of the PC 100 from the DNS server 220.

  When the registered flag is set to “1”, that is, when the IP address of the PC 100 is registered in the DNS server, the multi-function device 10 sets the IP address of the PC 100 to the DNS server. 220 is inquired (static name resolution is executed), but the IP address of the PC 100 is not inquired of the PC 100 (dynamic name resolution is not executed). This is because the multi-function device 10 can acquire the IP address of the PC 100 from the DNS server 220 by executing the static name resolution. According to this configuration, the multi-function device 10 does not needlessly perform dynamic name resolution.

(Effect of this embodiment)
This example has been described in detail. The multi-function device 10 receives the name resolution packet while the main CPU 20 is in the sleep state and determines that the IP address of the multi-function device 10 is registered in the DNS server 220 (ie, Name resolution unnecessary flag = “1”), the IP address of the multi-function device 10 is not transmitted as a response to the name resolution packet.

  It is desirable to reduce the power consumption of the sub CPU 40 when the sub CPU 40 is in the non-sleep state. This is to reduce power consumption in the sleep state of the multi-function device 10. If the sub CPU 40 executes a response to the name resolution packet while the main CPU 20 is in the sleep state, the processing capacity of the sub CPU 40 must be increased, and the sub CPU 40 is consumed in the non-sleep state. The power becomes high. Therefore, in order to reduce the power consumption in the sleep state of the multi-function device 10, it is desirable that the main CPU 20 executes a response to the name resolution packet.

  A device (for example, PC 100) connected to a network such as LAN 4 periodically performs name resolution by transmitting a name resolution packet to other devices in the network. Therefore, when a large number of devices are connected to the network, the multi-function device 10 shifts to the sleep state when a response is executed to the name resolution packet received from each of the large number of devices. Even so, it must immediately transition to the ready state. As a result, the power consumption of the multi-function device 10 cannot be reduced. According to the multi-function device 10 of the present embodiment, the above problem can be solved.

(Correspondence)
The multi-function device 10 is an example of a “communication device”. The DNS server 220 is an example of a “registration server”. The first signal transmission unit 30 is an example of a “first signal transmission unit”, the second signal transmission unit 32 is an example of a second signal transmission unit, and the signal determination unit 50 is an example of a “signal determination unit”. Name resolution unnecessary flag = “1” is an example of “predetermined information”, and registration completion information is an example of “specific signal”. The main CPU 20 and the sub CPU 40 are examples of the “processor”. A state where both the main CPU 20 and the sub CPU 40 are in the non-sleep state is an example of “high consumption state”, and a state where the main CPU 20 is in the sleep state and the sub CPU 40 is in the non-sleep state is an example of “low consumption state”. It is.

  As mentioned above, although embodiment of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

(Modification)
(1) In the above embodiment, the multi-function device 10 includes the two CPUs 20 and 40. However, the multi-function device 10 may include only the main CPU 20 instead. In this case, the frequency of the clock signal supplied to the main CPU 20 may be shifted between a low state and a high state. When the frequency of the clock signal is high, the power consumption of the main CPU 20 is relatively high, and when the frequency of the clock signal is low, the power consumption of the main CPU 20 is relatively low. In this modification, the main CPU 20 is an example of a “processor”, and a state in which the frequency of the clock signal supplied to the main CPU 20 is high is an example of a “high consumption state”. The frequency of the clock signal supplied to the main CPU 20 A low state is an example of a “low consumption state”.

(2) In the above embodiment, the multi-function device 10 includes the two RAMs 60 and 90. Alternatively, the multi-function device 10 may include only one RAM. In this case, one RAM may always be in the normal operation mode while the multi-function device 10 is powered on. In this modified example, one RAM is an example of a “memory unit”.

(3) In the above embodiment, the DHCP server 210 assigns an IP address to the multi-function device 10. However, the allocation server for assigning the IP address to the multi-function device 10 may be a BOOTP (BOOTstrap Protocol) server, a RARP (Reverse Address Resolution Protocol) server, or the like in addition to the DHCP server. When the RARP server is used, the user operates the RARP server to set the IP address to be set in the multi-function device 10, the subnet mask to be set in the multi-function device 10, and the Information in which the node name or the MAC address is associated may be registered in the RARP server.

(4) When the name resolution unnecessary flag is “1”, the multi-function device 10 does not have to execute dynamic name resolution (broadcast or multicast of name resolution packets). When the name resolution unnecessary flag is “1”, the IP address of another device (for example, the PC 300) connected to the LAN 4 may be registered in the DNS server 220 as in the multi-function device 10. Because it is expensive.

(5) When the multi-function device 10 is in the sleep state and the name resolution unnecessary flag is “1”, the user selects whether or not to execute a response process for the name resolution packet. It may be acceptable. When the user selects to execute the response process, the multi-function device 10 is in the sleep state and the name resolution unnecessary flag is “1”. The IP address of the multi-function device 10 may be transmitted.

(6) When the registered flag is set to “0”, the multi-function device 10 does not have to send the inquiry packet of the IP address of a specific device to the DNS server 220. That is, the multi-function device 10 may only transmit the inquiry packet of the IP address of a specific device by broadcast or multicast. This is because when the registered flag is set to “0”, the IP address of the specific device may not be recorded in the DNS server 220.

(7) In the above embodiment, the main CPU 20 executes the processing according to the program 82, thereby realizing the units 22 to 34. At least one of the units 22 to 34 is realized by hardware such as a logic circuit. May be. In addition, each unit 44 to 58 is realized by the sub CPU 40 executing a process according to a program, but at least one of each unit 44 to 58 may be realized by hardware such as a logic circuit.

(8) The “communication device” may not be a multi-function device, and may be a communication device such as a PC, a printer, a server, or a PDA.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

10: Multi-function device, 20: Main CPU, 22: IP address transmission unit, 24: Storage control unit, 26: Query unit, 28: Confirmation unit, 30: Signal transmission unit, 32: Signal transmission unit, 34: Registration Determination unit, 40: sub CPU, 44: registration determination unit, 46: storage control unit, 48: registration determination unit, 50: signal determination unit, 52: transition control unit, 54: signal transmission unit, 56: signal transmission unit, 200: Server, 210: DHCP server, 220: DNS server

Claims (10)

A communication device connected via a network to a registration server in which an IP address of a device connected to the network is registered;
A first registration determination unit that determines whether or not an IP address of the communication device is registered in the registration server;
An IP address inquiry signal for inquiring about the IP address of the communication device is received from a transmission source device connected to the network, and it is determined that the IP address of the communication device is registered in the registration server The IP address inquiry signal is received without transmitting the IP address of the communication apparatus to the transmission source device of the IP address inquiry signal, and the IP address of the communication apparatus An IP address transmission unit that transmits the IP address of the communication device to a transmission source device of the IP address inquiry signal when it is determined that the IP address inquiry signal is not registered in the registration server;
A communication device comprising: A storage control unit for storing predetermined information on whether or not the IP address of the communication device is registered in the registration server;
The first registration determination unit includes:
The communication apparatus according to claim 1, wherein it is determined whether or not the IP address of the communication apparatus is registered in the registration server using the predetermined information in the memory.   The storage control unit stores, in the memory, the predetermined information indicating that the IP address of the communication device is registered in the registration server when the IP address of the registration server is designated by a user. The communication device according to claim 2.   The storage control unit receives the specific signal transmitted from the registration server when the IP address of the communication apparatus is registered in the registration server, and the IP address of the communication apparatus is registered in the registration server. The communication apparatus according to claim 2, wherein the predetermined information indicating that the information is registered in a server is stored in the memory. An inquiry unit that inquires of the registration server whether or not the IP address of the communication device is registered in the registration server;
The storage control unit indicates that the IP address of the communication device is registered in the registration server when the specific signal transmitted from the registration server is received in response to the inquiry. The communication apparatus according to claim 4, wherein the information is stored in the memory. A confirmation unit for confirming whether or not communication with the registration server is possible after the predetermined information indicating that the IP address of the communication device is registered in the registration server is stored in the memory; Prepared,
The storage control unit deletes, from the memory, the predetermined information indicating that the IP address of the communication device is registered in the registration server when it is confirmed that communication with the registration server is not possible. The communication device according to any one of claims 3 to 5.   The signal determination unit according to claim 1, further comprising: a signal determination unit configured to determine whether the packet is the IP address inquiry signal based on a protocol type indicated by the packet received from the network. The communication apparatus as described in. With a processor that can be transitioned between a high power consumption state with relatively high power consumption and a low power consumption state with relatively low power consumption,
The processor includes the first registration determination unit and the IP address transmission unit.
The processor further includes a transition control unit that shifts the processor between the high consumption state and the low consumption state,
When the IP address inquiry signal is received while the processor is in the high consumption state, the IP address transmission unit determines whether the IP address of the communication device is registered in the registration server. Regardless of whether the IP address of the communication device is transmitted to the source device of the IP address inquiry signal,
When it is determined that the IP address inquiry signal is received and the IP address of the communication device is not registered in the registration server while the processor is in the low consumption state,
The transition control unit shifts the processor from the low consumption state to the high consumption state,
The IP address transmission unit transmits the IP address of the communication device to a transmission source device of the IP address inquiry signal,
When it is determined that the IP address inquiry signal is received and the IP address of the communication device is registered in the registration server while the processor is in the low consumption state,
The transition control unit does not shift the processor from the low consumption state to the high consumption state,
The communication apparatus according to claim 1, wherein the IP address transmission unit does not transmit the IP address of the communication apparatus toward a transmission source device of the IP address inquiry signal. A first signal transmission unit for transmitting, to the registration server, a first acquisition signal for acquiring an IP address of a specific device connected to the network from the registration server;
A second signal transmitter for transmitting a second acquisition signal for acquiring the IP address of the specific device from the specific device by at least one of broadcast and multicast;
A second registration determination unit that determines whether the IP address of the specific device is registered in the registration server when the IP address of the specific device is to be acquired; Prepared,
When it is determined that the IP address of the specific device is not registered in the registration server,
The second signal transmission unit transmits the second acquisition signal by at least one of broadcast and multicast,
Run
When it is determined that the IP address of the specific device is registered in the registration server,
The first signal transmission unit transmits the first acquisition signal to the registration server,
The communication device according to claim 1, wherein the second signal transmission unit does not transmit the second acquisition signal. A computer program for a communication device connected via a network to a registration server in which an IP address of a device connected to the network is registered,
In a computer mounted on the communication device,
A determination process for determining whether an IP address of the communication device is registered in the registration server;
An IP address inquiry signal for inquiring about the IP address of the communication device is received from a transmission source device connected to the network, and it is determined that the IP address of the communication device is registered in the registration server The IP address inquiry signal is not transmitted to the source device of the IP address inquiry signal, the IP address inquiry signal is received in the IP address transmission process, and IP address transmission for transmitting the IP address of the communication apparatus to the transmission source device of the IP address inquiry signal when it is determined that the IP address of the communication apparatus is not registered in the registration server Processing,
A computer program that executes

Images