JP2024059242A - COMMUNICATION CONTROL DEVICE, CONTROL METHOD FOR COMMUNICATION CONTROL DEVICE, AND PROGRAM - Google Patents

Abstract

[Problem] To realize packet routing by a communication control device connected to a plurality of mutually different networks in a more suitable manner. [Solution] A DFE 122 has a first network I/F unit 217 connected to a first network 101, and a second network I/F unit 218 connected to an MFP 121 via a second network 102. A network I/F status determination unit 311 determines whether the status of the second network I/F unit 218 is link down or not. A packet transmission unit 312 discards packets addressed to the MFP 121 when it is determined that the status of the second network I/F unit 218 is link down. [Selected Figure] Fig. 6

Description

This disclosure relates to a communication control device, a control method for a communication control device, and a program.

In recent years, many devices such as printers, scanners, FAXes, or image forming devices (MFPs: Multi Function Printers) that combine these functions have become equipped with a communication function for communicating with other devices via a network. For example, an MFP equipped with a communication function realizes a function for transmitting scan data to a PC and a function for notifying the server of information about itself (for example, information indicating an operating state) by communicating with a terminal device such as a server or a PC via a network. In addition, by using the communication function, it is also possible to connect a paper feeder for replenishing a large volume of paper to the MFP, a paper discharger for performing various post-processing processes on printed matter, and the like.
Also, so-called professional use products used in printing companies, design offices, etc., may require more advanced print control than so-called office products, such as image processing and print job scheduling. To meet such requirements, a print control device (DFE: Digital Front End controller) that controls the operation of the MFP may be applied. The DFE, for example, plays a role of mediating communication between the MFP and a server or a terminal device. Therefore, the DFE may be provided with a network I/F (Interface) for connecting to the MFP and a network I/F for connecting to a network (for example, a backbone network) to which the server or terminal device is connected.
In recent years, in order to strengthen network security, a mechanism has been introduced in which a server that monitors unauthorized connections is installed on the backbone network and suspicious packets are detected.

The sending and receiving of packets in network devices such as DFEs is controlled according to a routing table stored in the network devices. If the destination address of a received packet is registered in a destination network in the routing table, the packet is forwarded to the next hop corresponding to that destination network. On the other hand, if the destination address of a packet is not registered in a destination network in the routing table, the packet is processed within the network device. Patent Document 1 discloses the above-mentioned routing technology.

Another example of a network communication mechanism is the default gateway. By registering the default gateway setting in the routing table, when a network device receives a packet with an unknown destination, it becomes possible to control the packet so that the packet is forwarded to the router that is the default gateway.
As described above, the DFE has multiple network I/Fs. The network I/Fs for connecting the DFE and the MFP do not have a default gateway set because the DFE and the MFP communicate one-to-one. On the other hand, the network I/Fs for connecting the DFE and the backbone network have the IP address of a router on the backbone network set as the default gateway in order to connect to an external network.

Patent No. 3191740

Since multiple devices that perform one-to-one communication, such as a DFE and an MFP, each have their own individual power source, each device can start up independently. For example, a use case can be envisioned in which a DFE is started up independently and the rasterization and imposition functions it provides are used. In such a case, it is also conceivable that the power to the MFP may be turned off. In such a situation, from the DFE's perspective, the network I/F for connecting to the MFP is linked down, so the destination of the packet that the DFE is attempting to send to the MFP is unknown. In this case, the packet that was originally intended for the MFP is forwarded to the default gateway, and may be detected as a suspicious packet by a server that monitors unauthorized connections.

In view of the above problems, the present invention aims to realize packet routing in a more suitable manner by a communication control device connected to multiple different networks.

The communication control device according to the present invention is a communication control device having a first network interface connected to a first network and a second network interface connected to a device to be managed via a second network different from the first network, and has a control means for controlling packets received via the first network interface and addressed to the device to be sent to the device via the second network interface, and a first determination means for determining whether the state of the second network interface is link down, and the control means is characterized in that when the first determination means determines that the state of the second network interface is link down, the control means discards the packets addressed to the device.

The present invention makes it possible to realize packet routing in a more suitable manner by a communication control device connected to multiple different networks.

FIG. 1 illustrates an example of a system configuration of a printing system. FIG. 2 is a diagram illustrating an example of a hardware configuration of a DFE. FIG. 2 is a diagram illustrating an example of a software configuration of a DFE. FIG. 2 illustrates an example of a hardware configuration of an MFP. FIG. 2 is a diagram illustrating an example of a software configuration of the MFP. 11 is a flowchart showing an example of a process of a DFE. 10 is a flowchart showing an example of a process of an MFP. 11 is a flowchart showing an example of a process of a DFE. 11 is a flowchart showing an example of a process of a DFE. 11 is a flowchart showing an example of a process of a DFE. 11 is a flowchart showing an example of a process of a DFE. 11 is a flowchart showing an example of a process of a DFE. 13 is a diagram showing an example of a table used by a DFE for communication control. FIG. 11 is a diagram showing an example of a sleep condition.

A preferred embodiment of the present disclosure will be described in detail below with reference to the attached drawings. Note that in this specification and drawings, components having substantially the same functional configuration are designated by the same reference numerals to avoid redundant description.

<System Configuration>
An example of a system configuration of a printing system according to an embodiment of the present disclosure will be described with reference to Fig. 1. The printing system according to the present embodiment includes an MFP 122, a DFE 121, a terminal device 111, an unauthorized connection monitoring server 131, and a router 142.
The DFE 121, the terminal device 111, the unauthorized connection monitoring server 131, and the router 142 are connected via a first network 101. In the example shown in Fig. 1, the first network 101 is assigned a subnetwork of "172.33.22.0/24". The first network 101 also functions as a backbone network in the printing system according to this embodiment.
The DFE 121 and the MFP 122 are connected via a second network 102. In the example shown in FIG. 1, the second network 102 is assigned a subnet of "10.100.1.0/24". In this case, an IP address such as "10.100.1.1" is assigned to the network I/F of the DFE 121 connected to the MFP 122. The second network 102 is used for transferring image data used for printing, exchanging information between the DFE 121 and the MFP 122, and the like. Note that, as long as it is possible to realize the functions of the printing system according to this embodiment, the form of the second network 102 is not particularly limited, and may be, for example, a single network or multiple networks.

The unauthorized connection monitoring server 131 monitors packets transmitted via the first network 101. For example, the unauthorized connection monitoring server 131 has a function of issuing a warning to the network administrator if it detects a large volume and high frequency of packet transmissions or a suspicious packet such as a packet with an unreliable source or an unreliable destination.

In the printing system according to this embodiment, a print job is transmitted from the terminal device 111 to the DFE 121 via the first network 101. The DFE 121 sequentially performs rasterization processing on the print job received from the terminal device 111, and then transfers the print job to the MFP 122. When a print job is transferred from the DFE 121, the MFP 122 performs various processes on the print job (e.g., image processing according to print settings, etc.), and then prints an image indicated by the print job on a recording medium such as paper.
The router 142 is connected to the external network 141 via a third network.

<Hardware configuration of DFE>
An example of the hardware configuration of the DFE 121 will be described with reference to Fig. 2. The DFE 121 has a controller unit including a CPU (Central Processing Unit) 211, a ROM (Read Only Memory) 212, and a RAM (Random Access Memory) 213. The DFE 121 also has a display/operation device I/F unit 214, a storage device I/F unit 215, a storage device 230, a first network I/F unit 217, a second network I/F unit 218, and a printer device I/F unit 216. A display/operation device 220 is connected to the display/operation device I/F unit 214.

The control program for controlling the operation of DFE121 is stored, for example, in ROM212. The control program is deployed in RAM213 and then executed by CPU211, thereby making it possible to control the operation of DFE121 and realize the functions provided by DFE121.

The first network I/F unit 217 is a network interface for connecting the DFE 121 to the first network 101. The configuration of the first network I/F unit 217 may be changed as appropriate depending on the type of the first network 101 and the communication method applied.
Similarly, the second network I/F unit 218 is a network interface for connecting the DFE 121 to the second network 102. The configuration of the second network I/F unit 218 may also be changed as appropriate depending on the type of the second network 102 and the communication method applied.
The printer device I/F unit 216 is an interface for connecting the DFE 121 and the MFP 122 via a transmission path different from the second network 102. For example, image data of a print job (i.e., data of an image to be printed) may be transmitted and received between the DFE 121 and the MFP 122 via the printer device I/F unit 216.

The storage device 230 is a storage area for storing various data, programs, etc. Furthermore, the storage device I/F unit 215 stores various data in the storage device 230 and reads out data stored in the storage device 230. For example, data transmitted from the MFP 122 is held by being stored in the storage device 230 via the storage device I/F unit 215. Furthermore, the data stored in the storage device 230 is read out from the storage device 230 via the storage device I/F unit 215.
The display/operation device I/F 214 displays information on the display/operation device 220 to present the information to the user, or receives user operations (in other words, instructions from the user) via the display/operation device 220. For example, the display/operation device I/F 214 may change the information displayed on the display/operation device 220 according to the received user operation or the state of the DFE 121. The display/operation device 220 is a schematic representation of an input/output device that serves as an output interface for presenting information to the user and an input interface for receiving instructions from the user. The display/operation device 220 may be realized, for example, by a display equipped with a touch panel.

<Software configuration of DFE>
An example of the software configuration of the DFE 121 will be described with reference to Fig. 3. The software configuration illustrated in Fig. 3 is realized, for example, by a program stored in the ROM 212 or the storage device 230 being loaded into the RAM 213 and executed by the CPU 211. The DFE 121 includes a print control module 300, a communication management module 310, and an operating system 320.

The print control module 300 controls print jobs received from the terminal device 111, applies rasterization processing to image data, acquires device information from the MFP 122, and transmits print jobs to the MFP 122. Acquisition of device information from the MFP 122 and transmission of print jobs to the MFP 122 are achieved by sending and receiving data (packets) to and from the MFP 122. Data is sent and received to and from the MFP 122 via the communication management module 310. In this embodiment, the print control module 300 periodically acquires information from the MFP 122 using a management information base (MIB) or a proprietary protocol to update the operating status and paper feed stage information of the MFP 122.

The communications management module 310 includes a network I/F state determination unit 311, a packet transmission unit 312, a sleep determination unit 313, and a power state determination unit 315. The communications management module 310 also holds a sleep return packet list 314.
The network I/F state determination unit 311 determines whether the state of the second network I/F unit 218 is a link up state or a link down state via a second network I/F processing unit 322 described later.
The packet transmission unit 312 generates a packet instructed by the print control module 300, and instructs the operating system 320 to transmit the generated packet.
The sleep determination unit 313 determines whether the MFP 122 is in a sleep state. Sleep means that the computer operation is temporarily stopped and the MFP 122 is put into standby in a power-saving state. For example, a state in which the MFP 122 has entered a power-saving mode corresponds to an example of the sleep state. The management of the sleep state will be described in detail later.
The power state determination unit 315 determines the power state of the MFP 122. The power state indicates whether the power of the MFP 122 is in an on state or an off state.

The sleep recovery packet list 314 is data in which a list of packets for waking up the MFP 122 from sleep is recorded. The sleep recovery packet list 314 is stored in the storage device 230.
For example, Fig. 13A shows an example of the sleep recovery packet list 314. In this embodiment, a print job 1301 and a sleep recovery command 1302 are listed in the sleep recovery packet list 314 as packet applications. The print job 1301 indicates a packet used when a print job received from the terminal device 111 is transmitted to the MFP 122. The sleep recovery command 1302 indicates a command used when waking the MFP 122 from sleep under circumstances other than when a print job is transmitted. This command is used to wake the MFP 122 from sleep when the print control module 300 issues an instruction other than a print job, such as an instruction to adjust color, to the MFP 122, for example.

The operating system 320 includes a network setting management unit 323, a first network I/F processing unit 321, and a second network I/F processing unit 322. The operating system 320 also holds a routing table 324.

The network setting management unit 323 manages network settings, such as an IP address, a subnet mask, and a default gateway, which are set in each of the first network I/F processing unit 321 and the second network I/F processing unit 322 .
A default gateway is a network device that connects an internal network to an external network. A default gateway is generally a router within an internal network.
As a specific example, in the routing table, "0.0.0.0/0" is set as the default gateway in the destination network, and the next hop is registered as the IP address of the router. By applying such settings, the network device sends packets with unknown destinations to the default gateway, and the default gateway router further forwards the packets according to its own routing table. This mechanism enables the connection between external networks and internal networks.
As described above, the DFE 121 has two network I/Fs. In the network I/F for connecting to the MFP 122, a default gateway may not be set in the case of one-to-one communication between the DFE 121 and the MFP 122. On the other hand, the network I/F for connecting to the backbone network needs to connect to an external network, so the IP address of a router on the backbone network is set as the default gateway.
Furthermore, when the network setting management unit 323 is instructed by the packet transmission unit 312 to transmit a packet, the network setting management unit 323 determines a forwarding destination of the packet by referring to the routing table 324. Then, the network setting management unit 323 instructs the first network I/F processing unit 321 and the second network I/F processing unit 322 to transmit the packet.

The routing table 324 is stored in the storage device 230. Here, an example of the routing table 324 will be described with reference to FIG. 13B. In the routing table 324, a destination network 1311, a next hop 1312, and a network I/F 1313 are registered in association with each other. In an entry 1315 (the row marked with 1315), a routing setting for the terminal device 111 is registered. In addition, in an entry 1316, a routing setting for the MFP 122 is registered. In addition, the entry 1314 corresponds to a default gateway setting. That is, a packet whose destination is not registered in the routing table 324 (for example, a packet whose destination is unknown) is transferred according to the setting indicated in the entry 1314.
For example, when the network setting management unit 323 receives an instruction to transmit a packet with "10.100.1.2" specified as the destination, a search is performed on the destination network 1311 in the routing table 324, and an entry 1315 is found. Based on the information on the network I/F 1313 and the next hop 1312, the network setting management unit 323 instructs the second network I/F processing unit 322 to transmit the packet with "10.100.1.2" specified as the destination.
As another example, when the network setting management unit 323 receives an instruction to transmit a packet with "192.133.122.1" specified as the destination, a search is performed for the destination network 1311 in the routing table 324. In this case, since neither entry 1315 nor 1316 applies, entry 1314 registered as the default gateway is hit. Based on the information on the network I/F 1313 and the next hop 1312, the network setting management unit 323 instructs the first network I/F processing unit 321 to transmit the packet with "172.33.22.254" specified as the destination.

The first network I/F processing unit 321 transmits and receives packets to and from devices connected to the first network 101 (for example, the terminal device 111 and the router 142 ).
The second network I/F processing unit 322 transmits and receives packets to and from the MFP 122 via the second network 102 .

<MFP Hardware Configuration>
An example of the hardware configuration of the MFP 122 will be described with reference to Fig. 4. The MFP 122 is connected to a scanner 420, which is an image input device, and a printer engine 401, which is an image output device, and performs control for reading an original to generate image data and printing an image represented by the image data on a recording medium such as paper.

The MFP 122 includes a CPU 402 , a RAM 403 , a ROM 407 , a HDD 408 , an operation unit I/F 404 , and a first network I/F 418 .
The CPU 402 is a central processing unit for controlling the overall operation of the MFP 122. The RAM 403 functions as a system work memory for the operation of the CPU 402, and is also used as an image memory for temporarily storing input image data. The ROM 407 corresponds to a boot ROM, and stores a boot program for the system. The HDD 408 corresponds to an auxiliary storage device such as a hard disk drive, and stores system software for implementing various processes, input image data, and the like.
The operation unit I/F 404 is an interface unit for connecting an operation unit 419 having a display screen capable of displaying an image or the like indicated by image data to the MFP 122, and outputs operation screen data to the operation unit 419. The operation unit I/F 404 also plays a role in transmitting information input by an operator from the operation unit 419 to the CPU 402.
The first network I/F 418 is realized by, for example, a LAN (Local Area Network) card, and is connected to a network to input and output information between the first network I/F 418 and an external device.
The above units are arranged on a system bus 423 .

The image bus I/F 409 is an interface for connecting the system bus 423 and an image bus 424 that transfers image data at high speed, and is a bus bridge that converts the data structure.
Connected to the image bus 424 are a raster image processor (RIP) 411 , a device I/F 412 , a scanner image processing unit 413 , a printer image processing unit 414 , an image editing image processing unit 415 , and a color management module (CMM) 410 .
The raster image processor 411 is a so-called raster image processor, and develops a page description language (PDL) into a raster image.
A device I/F unit 412 performs synchronous/asynchronous conversion of image data with a scanner 420 or a printer engine 401 .
A scanner image processing unit 413 performs various processes such as correction, modification, and editing on image data input from a scanner 420 .
A printer image processing unit 414 performs processes such as correction and resolution conversion according to the printer engine on image data to be printed.
The image editing image processing unit 415 executes various image processing operations such as rotating an image indicated by image data and compressing and expanding image data.
The color management module 410 is a dedicated hardware module that performs color conversion processing (also called color space conversion processing) on image data based on a profile and calibration data. A profile is information such as a function for converting a color image expressed in a device-dependent color space into a device-independent color space (e.g., Lab, etc.). Calibration data is data for correcting the color reproduction characteristics of the scanner 420 and the printer engine 401 in the MFP 122.

The power control unit 416 is a control unit that controls the on/off of the power supply to the MFP 122. The switch 417 is an input interface that accepts a power on operation or a power off operation from the user. When the switch 417 is operated, an interrupt is issued from the power control unit 416 to the CPU 402. When the CPU 402 detects this interrupt, it controls the power control unit 416 in accordance with the state. As a result, the power state of the MFP 122 is selectively switched between an on state in which power is supplied to the MFP 122 and an off state in which power supply to the MFP 122 is stopped.
The paper feed stage control unit 421 is a module that controls paper setting information and paper feeding to the paper feed stage 422. The paper feed stage control unit 421 holds setting information acquired from the operation unit 419 and paper information (hereinafter also referred to as paper information) detected by the paper feed stage 422, and controls the paper feed stage 422 so as to feed paper according to the paper used by the print job during printing.

<Software Configuration of MFP 122>
An example of the software configuration of the MFP 122 will be described with reference to Fig. 5. A program for implementing each component shown in Fig. 5 is stored, for example, in the ROM 407 of the MFP 122. That is, the program is deployed in the RAM 407 and executed by the CPU 402 to implement the software configuration shown in Fig. 5. The MFP 122 includes a network setting management unit 501, a first network I/F processing unit 502, and a power management unit 503. The MFP 122 also holds a sleep condition 504.

The first network I/F processing unit 502 transmits and receives packets to and from the DFE 121 via the first network I/F 418 and the second network 102 .
The network setting management unit 501 manages network settings such as an IP address, a subnet mask, and a default gateway that are set in the first network I/F 418 .
The power management unit 503 manages the power state of the MFP 122. As a specific example, it is assumed that the switch 417 has received an operation to enable the power supply to the MFP 122 (hereinafter also referred to as a power-on operation). In this case, the power management unit 503 starts each piece of hardware, such as the scanner 420 and the printer engine 401, and starts each component, such as the network setting management unit 501 and the first network I/F processing unit 502. As another example, it is assumed that the switch 417 has received an operation to stop the power supply to the MFP 122 (hereinafter also referred to as a power-off operation). In this case, the power management unit 503 stops each piece of hardware, such as the scanner 420 and the printer engine 401, and stops each component, such as the network setting management unit 501 and the first network I/F processing unit 502.
Furthermore, while the MFP 122 is in an on state where power is supplied to the MFP 122, the power management unit 503 manages the sleep state of the MFP 122 in accordance with the sleep conditions 504. As described above, the state in which the MFP 122 has transitioned to a power saving mode corresponds to an example of the sleep state. When the power management unit 503 transitions to the sleep state, it achieves power saving by turning off the power of some of the hardware, such as the operation unit 419, the scanner 420, and the printer engine 401.

Now, referring to FIG. 14, an example of the sleep condition 504 will be described. The sleep condition 504 includes a sleep transition condition 1401 corresponding to the condition for transitioning the MFP 122 to a sleep state, and a sleep return condition 1402 corresponding to the condition for waking the MFP 122 from the sleep state. For example, in the example shown in FIG. 14, if the MFP 122 does not receive a packet for 60 seconds, the sleep transition condition 1401 is satisfied, and the power management unit 503 starts processing to transition the MFP 122 to a sleep state. On the other hand, if the MFP 122 receives a packet, the sleep return condition 1402 is satisfied, and the power management unit 503 starts processing to return the MFP 122 from the sleep state.

First Embodiment
An example of a printing system according to the first embodiment of the present disclosure will be described with reference to Fig. 6, focusing particularly on a packet transmission process by the DFE 121. The series of processes shown in Fig. 6 is realized, for example, by a program stored in the ROM 212 or the storage device 230 being loaded into the RAM 213 and executed by the CPU 211. In addition, the series of processes shown in Fig. 6 is executed, for example, when the print control module 300 transmits a packet addressed to the MFP 122.

In S601, the network I/F status determination unit 311 of the DFE 121 detects the status of the second network I/F unit 218, i.e., a link-up status or a link-down status. The status (link-up status, link-down status) of the second network I/F unit 218 is detected, for example, by using a network I/F status confirmation command provided by the operating system 320. Then, in S602, the network I/F status determination unit 311 determines whether the status of the second network I/F unit 218 is a link-down status.
If the network I/F status determination unit 311 determines in S602 that the second network I/F unit 218 is not in a link-down state, the process proceeds to S603.
On the other hand, if the network I/F status determination unit 311 determines in S602 that the second network I/F unit 218 is in a link-down state, the process proceeds to S604.

In S603, the packet sending unit 312 instructs the network setting management unit 323 to send the packet addressed to the MFP 122 received from the print control module 300. When the packet addressed to the MFP 122 (i.e., addressed to 10.100.1.2) is sent in S603, the second network I/F unit 218 is in a link-up state, as indicated by the determination result in S602. The network setting management unit 323 instructs the second network I/F processing unit 322 to send the packet addressed to 10.100.1.2 according to the information indicated in entry 1316 of the routing table 324. This controls the packet addressed to the MFP 122 to be sent to that MFP 122.

In S604, the packet sending unit 312 discards the packet addressed to the MFP 122 received from the print control module 300. In other words, in this case, the network setting management unit 323 does not refer to the routing table 324 or send the packet to the second network I/F processing unit 322.

Here, a supplementary explanation will be given on the problem that may occur when the technology according to this embodiment is not applied. For example, when the second network I/F unit 218 is linked down, the entry 1316 in which the network I/F column 1313 is set to "second network I/F" is deleted from the routing table 324. That is, the routing table 324 is in the state shown in FIG. 13C. At this time, when the packet transmission unit 312 instructs the network setting management unit 323 to transmit a packet addressed to the MFP 122 (i.e., addressed to 10.100.1.2), the entry 1314 registered as the default gateway is hit in the routing table 324. Therefore, the network setting management unit 323 instructs the first network I/F processing unit 321 to transmit a packet addressed to the MFP 122 according to the information registered in the entry 1314. Therefore, a packet addressed to MFP 122 is sent to the first network 101, and as a result, the packet is detected as a suspicious packet by the unauthorized connection monitoring server 131.

As described above, in this embodiment, if the second network I/F unit 218 is linked down, the packet sending unit 312 discards packets addressed to the MFP 122. This mechanism makes it possible to prevent a situation in which a packet addressed to the MFP 122 is sent to the first network 101 and detected as a suspicious packet.

Second Embodiment
A second embodiment of the present disclosure will be described below. In the above-described first embodiment, an example of a mechanism for preventing a situation in which a packet addressed to the MFP 122 is detected as a suspicious packet by discarding the packet when the second network I/F unit 218 is linked down has been described. On the other hand, even if the second network I/F unit 218 is not linked down, a situation in which the MFP 122 is in a sleep state may be assumed. In such a situation, a packet may be sent to the MFP 122, causing the MFP 122 to return from sleep. Therefore, in this embodiment, an example of a case in which a packet addressed to the MFP 122 is discarded when the MFP 122 is in a sleep state, preventing the MFP 122 from returning from sleep will be described.

First, an example of the power management process in the MFP 122 according to this embodiment will be described with reference to FIG. 7. The series of processes shown in FIG. 7 is realized, for example, by a program stored in the ROM 407 or HDD 408 mounted on the MFP 122 being expanded into the RAM 403 and executed by the CPU 402. The series of processes shown in FIG. 7 is also executed, for example, when the power is turned on via the switch 417.

In step S701, the power management unit 503 starts the startup process of the MFP 122. As a specific example, the power management unit 503 starts the startup process of each piece of hardware such as the operation unit 419, the scanner 420, and the printer engine 401.
In step S702, the power management unit 503 transmits a boot start event to the DFE 121. The boot start event is an event indicating that the power management unit 503 has started the boot process of the MFP 122. The event is packetized and transmitted to the DFE 121 via the network setting management unit 501.
In S703, the power management unit 503 completes the startup process.

In S704, the power management unit 503 determines whether the MFP 122 is in a sleep state. Note that transition to the sleep state and return from the sleep state are performed in S706 and S709, which will be described later. Therefore, for example, the power management unit 503 stores information indicating the execution results of each process, which enables the power management unit 503 to determine whether the MFP 122 is in a sleep state.
If the power management unit 503 determines in step S704 that the MFP 122 is in a sleep state, the process proceeds to step S705.
On the other hand, if the power management unit 503 determines in step S704 that the MFP 122 is not in the sleep state, the process proceeds to step S708.

In step S705, the power management unit 503 refers to the sleep recovery condition 1402 included in the sleep condition 504, and determines whether the sleep recovery condition is satisfied.
If the power management unit 503 determines in step S705 that the sleep return condition is satisfied, the process proceeds to step S706.
On the other hand, if the power management unit 503 determines in step S705 that the sleep return condition is not satisfied, the process proceeds to step S711.

In step S706, the power management unit 503 restores the MFP 122 from the sleep state. As a specific example, the power management unit 503 transitions the components, such as the operation unit 419, the scanner 420, and the printer engine 401, that have been switched to the power-off state due to the transition to the sleep state, to the power-on state.
In S707, the power management unit 503 transmits a sleep return event to the DFE 121. The sleep return event is an event indicating that the power management unit 503 has completed a process of returning the MFP 122 from a sleep state (hereinafter, also referred to as a sleep return process). The event is packetized and transmitted to the DFE 121 via the network setting management unit 501.

In step S708, the power management unit 503 refers to the sleep transition condition 1401 included in the sleep condition 504, and determines whether the sleep transition condition is satisfied.
If the power management unit 503 determines in step S708 that the sleep transition condition is satisfied, the process proceeds to step S709.
On the other hand, if the power management unit 503 determines in step S708 that the sleep transition condition is not satisfied, the process proceeds to step S711.

In step S709, the power management unit 503 transitions the MFP 122 to a sleep state. As a specific example, the power management unit 503 transitions components that stop operating in the sleep state, such as the operation unit 419, the scanner 420, and the printer engine 401, to a power-off state.
In S710, the power management unit 503 transmits a sleep transition event to the DFE 121. The sleep transition event is an event indicating that the process of the power management unit 503 transitioning the MFP 122 to a sleep state (hereinafter also referred to as sleep transition process) has been completed. The event is packetized and transmitted to the DFE 121 via the network setting management unit 501.

In step S711, the power management unit 503 determines whether or not a power-off operation has been performed via the switch 417.
If the power management unit 503 determines in step S711 that a power-off operation has been performed, the process proceeds to step S712.
On the other hand, if the power management unit 503 determines in step S711 that the power-off operation has not been performed, the process proceeds to step S704. In this case, the processes from step S704 onward are executed again.

In S712, the power management unit 503 starts processing (hereinafter also referred to as shutdown processing) to shut down the MFP 122. As a specific example, the power management unit 503 starts shutdown processing of components such as the operation unit 419, the scanner 420, and the printer engine 401.
In S713, the power management unit 503 transmits a shutdown start event to the DFE 121. The shutdown start event is an event indicating that the power management unit 503 has started a shutdown process. The event is packetized and transmitted to the DFE 121 via the network setting management unit 501.
In step S714, the power management unit 503 completes the shutdown process, and ends the series of processes shown in FIG.

Next, referring to FIG. 8, an example of the processing of the DFE 121 according to this embodiment will be described, focusing on the process of receiving an event sent from the MFP 122. The series of processing shown in FIG. 8 is realized, for example, by a program stored in the ROM 211 or storage device 230 mounted on the DFE 121 being expanded into the RAM 213 and executed by the CPU 211. The series of processing shown in FIG. 8 is also executed, for example, when the communication management module 310 receives an event (packet) from the MFP 122.

In S801, the sleep determination unit 313 determines whether or not the series of processes shown in FIG.
If the sleep determination unit 313 determines in S801 that the series of processes shown in FIG. 8 has been called for the first time since the DFE 121 was started, the sleep determination unit 313 advances the process to S802.
On the other hand, if the sleep determination unit 313 determines in S801 that the series of processes shown in FIG. 8 has not been called for the first time since the DFE 121 was started, the sleep determination unit 313 advances the process to S803.

In S802, the sleep determination unit 313 turns off the sleep flag. The sleep flag is a flag held in the sleep determination unit 313, and is used to manage the sleep state of the MFP 122. Specifically, when the sleep flag is on, it indicates that the MFP 122 is in a sleep state, and when the sleep flag is off, it indicates that the MFP 122 is not in a sleep state.

In S<b>803 , the sleep determination unit 313 determines whether or not a sleep transition event has been received from the MFP 122 .
If the sleep determination unit 313 determines in step S803 that a sleep transition event has been received from the MFP 122, the process proceeds to step S804.
On the other hand, if the sleep determination unit 313 determines in step S803 that a sleep transition event has not been received from the MFP 122, the process proceeds to step S805.
In S804, the sleep determination unit 313 turns on the sleep flag.

In S<b>805 , the sleep determination unit 313 determines whether or not a sleep return event has been received from the MFP 122 .
If the sleep determination unit 313 determines in step S805 that a sleep return event has been received from the MFP 122, the process proceeds to step S806.
On the other hand, if the sleep determination unit 313 determines in step S805 that the sleep return event has not been received from the MFP 122, the series of processes shown in FIG. 8 ends.
In S806, the sleep determination unit 313 turns off the sleep flag.

Next, referring to FIG. 9, an example of the processing of the DFE 121 according to this embodiment will be described with a focus on the packet transmission processing. The series of processing shown in FIG. 9 is realized, for example, by a program stored in the ROM 211 or storage device 230 mounted on the DFE 121 being expanded into the RAM 213 and executed by the CPU 211. The series of processing shown in FIG. 9 is also executed, for example, when the print control module 300 transmits a packet addressed to the MFP 122. Note that the processing of S601 to S604 is substantially similar to the processing of S601 to S604 shown in FIG. 6, and therefore a detailed description thereof will be omitted.

If the network I/F status determination unit 311 determines in S602 that the second network I/F unit 218 is not in a link-down state, the process proceeds to S901.
In S901, the sleep determination unit 313 determines whether or not the sleep flag is on.
If the sleep determination unit 313 determines in S901 that the sleep flag is on, that is, if the MFP 122 is in a sleep state, the process proceeds to S603. In this case, in S603, the packet transmission unit 312 instructs the network setting management unit 323 to transmit the packet addressed to the MFP 122, which has been accepted from the print control module 300.
On the other hand, if the sleep determination unit 313 determines in S901 that the sleep flag is off, that is, if the MFP 122 is not in a sleep state, the process proceeds to S604. In this case, in S604, the packet transmission unit 312 discards the packet addressed to the MFP 122 and accepted from the print control module 300.

As described above, in this embodiment, even if the second network I/F unit 218 is not linked down, packets addressed to the MFP 122 are discarded if the MFP 122 is in a sleep state. By applying this type of control, it is possible to prevent the occurrence of a situation in which the MFP 122 returns from a sleep state due to a packet sent from the DFE 121.

Third Embodiment
A third embodiment of the present disclosure will be described below. In the above-mentioned second embodiment, an example of a case where a packet addressed to the MFP 122 is discarded when the MFP 122 is in a sleep state even when the second network I/F unit 218 is not linked down has been described. On the other hand, in the above-mentioned situation, it may not be preferable to discard all packets. As a specific example, even when the DFE 121 transmits a packet for transmitting a print job to the MFP 122, a situation where the packet is discarded may be assumed. In such a situation, the user manually restores the MFP 122 from a sleep state by operating the operation unit 419 of the MFP 122 in order to cause the MFP 122 to execute printing. In view of such a situation, in this embodiment, an example of a mechanism for automatically restoring the MFP 122 from a sleep state will be described by controlling the packet for sleep restoration to be transmitted to the MFP 122 even when the MFP 122 is in a sleep state.

Figure 10 shows an example of a packet transmission process of the DFE 121 according to this embodiment. The series of processes shown in Figure 10 is realized, for example, by a program stored in the ROM 211 or storage device 230 mounted on the DFE 121 being expanded into the RAM 213 and executed by the CPU 211. The series of processes shown in Figure 10 is also executed, for example, when the print control module 300 transmits a packet addressed to the MFP 122. Note that the processes of S601 to S604 and S901 are substantially similar to the processes of S601 to S604 and S901 shown in Figure 9, and therefore detailed description thereof will be omitted.

If the sleep determination unit 313 determines in S901 that the sleep flag is off, that is, if the sleep determination unit 313 determines that the MFP 122 is not in a sleep state, the process proceeds to S1001.
In S1001, the sleep determination unit 313 determines whether a packet addressed to the MFP 122 received from the print control module 300 (in other words, a packet to be sent) is a packet for return from sleep, based on information registered in the return from sleep packet list 314. Specifically, the sleep determination unit 313 searches the return from sleep packet list 314 for information corresponding to the packet received from the print control module 300, and when matching information is found, the sleep determination unit 313 regards the packet as a packet for return from sleep.
If the sleep determination unit 313 determines in S1001 that the packet addressed to the MFP 122 received from the print control module 300 is a packet for returning from sleep, the process proceeds to S603. In this case, in S603, the packet transmission unit 312 instructs the network setting management unit 323 to transmit the packet addressed to the MFP 122 received from the print control module 300.
On the other hand, if the sleep determination unit 313 determines in S1001 that the packet addressed to the MFP 122 received from the print control module 300 is not a packet for returning from sleep, the process proceeds to S604. In this case, in S604, the packet transmission unit 312 discards the packet addressed to the MFP 122 received from the print control module 300.

As described above, in this embodiment, even if the MFP 122 is in a sleep state, if a packet addressed to the MFP 122 is a packet for returning from a sleep state, the packet is sent to the MFP 122. By applying such control, it becomes possible to automatically return the MFP 122 from the sleep state.

Fourth Embodiment
A fourth embodiment of the present disclosure will be described below. In the above-described first embodiment, an example of a case where a packet addressed to the MFP 122 is discarded when the second network I/F unit 218 is in a link-down state has been described. On the other hand, in a situation where the MFP 122 is executing a shutdown process, it may be difficult to discard a packet depending on the timing.
As a specific example, when detecting the link-up state or the link-down state of the second network I/F unit 218 in S601 of Fig. 6, the power may not be completely turned off and the second network I/F unit 218 may be determined to be linked up. Furthermore, if the second network I/F unit 218 is linked down immediately after the processing of S601 and the routing table 324 is in the state illustrated in Fig. 13C, a packet may be sent to the MFP 122. Under such circumstances, the entry 1314 registered as the default gateway in the routing table 324 is hit. Therefore, in this case, the network setting management unit 323 instructs the first network I/F processing unit 321 to send a packet addressed to the MFP 122 according to the information registered in the entry 1314. Therefore, the packet addressed to the MFP 122 is sent to the first network 101, and as a result, the packet is detected as a suspicious packet by the unauthorized connection monitoring server 131.
In consideration of the above problem, in this embodiment, when the MFP 122 starts a shutdown process, the DFE 121 discards packets addressed to the MFP 122. By applying such control in this embodiment, it is possible to prevent a situation in which packets addressed to the MFP 122 are sent to the first network 101, regardless of the timing of the shutdown process of the MFP 122.

First, referring to FIG. 11, an example of the processing of the DFE 121 according to this embodiment will be described with a focus on the event reception processing. The series of processing shown in FIG. 11 is realized, for example, by a program stored in the ROM 211 or storage device 230 mounted on the DFE 121 being expanded into the RAM 213 and executed by the CPU 211. The series of processing shown in FIG. 11 is also executed, for example, when the communication management module 310 receives an event (packet) from the MFP 122. Note that the processing of S801 to S806 is substantially similar to the processing of S801 to S806 shown in FIG. 8, and therefore a detailed description thereof will be omitted.

11 is called for the first time after the start of the DFE 121, the sleep determination unit 313 advances the process to S802 and executes the process of S802. After that, the power state determination unit 315 executes the process of S1101.
In S1101, the power state determination unit 315 turns off the power flag. The power flag is a flag held in the power state determination unit 315, and is used to manage the power state of the MFP 122. Specifically, when the power flag is on, it indicates that the MFP 122 is in a power-on state, and when the power flag is off, it indicates that the MFP 122 is in a power-off state. The power-on state indicated by the power flag is reflected in the power flag at the timing when the MFP 122 starts a process to turn on the power. That is, even if the MFP 122 has not transitioned to a power-on state, the power flag becomes an on state at the timing when the process to turn on the power is started. Similarly, the power-off state indicated by the power flag is reflected in the power flag at the timing when the MFP 122 starts a process to turn off the power. That is, even if the MFP 122 has not transitioned to a power-off state, the power flag becomes an off state at the timing when the process to turn off the power is started. In this embodiment, various explanations will be given on the assumption that the DFE 121 is turned on before the MFP 122 .

In S1102, the power state determination unit 315 determines whether or not a boot start event has been received from the MFP 122. The boot start event is an event that is transmitted by the power management unit 503 of the MFP 122 in S702 of FIG.
If the power state determining unit 315 determines in S1102 that a boot start event has been received from the MFP 122, the process proceeds to S1103. In this case, in S1103, the power state determining unit 315 turns on the power flag.
On the other hand, if the power state determining unit 315 determines in step S1102 that a boot start event has not been received from the MFP 122, the process proceeds to step S1104.

In S1104, the power state determination unit 315 determines whether or not a shutdown start event has been received from the MFP 122. The shutdown start event is an event that is transmitted by the power management unit 503 of the MFP 122 in S713 of FIG.
If the power state determining unit 315 determines in S1104 that a shutdown start event has been received from the MFP 122, the process proceeds to S1105. In this case, in S1105, the power state determining unit 315 turns off the power flag.
On the other hand, if the power state determining unit 315 determines in step S1104 that a shutdown start event has not been received from the MFP 122, the process proceeds to step S803.
As described above, the processes from S803 onwards are substantially similar to the example shown in FIG.

Next, referring to FIG. 12, an example of the processing of the DFE 121 according to this embodiment will be described with a focus on the packet transmission processing. The series of processing shown in FIG. 12 is realized, for example, by a program stored in the ROM 211 or storage device 230 mounted on the DFE 121 being loaded into the RAM 213 and executed by the CPU 211. The series of processing shown in FIG. 12 is also executed, for example, when the print control module 300 transmits a packet addressed to the MFP 122. Note that the processing of S601 to S604, S901, and S1001 is substantially similar to the processing of S601 to S604, S901, and S1001 shown in FIG. 10, and therefore detailed description thereof will be omitted.

In S1201, the power state determining unit 315 determines whether the power flag is off.
If the power state determination unit 315 determines in S1201 that the power flag is off, that is, if the MFP 122 is in a shutdown state, the process proceeds to S604. In this case, in S604, the packet transmission unit 312 discards the packet addressed to the MFP 122 and accepted from the print control module 300.
On the other hand, if the power status determination unit 315 determines in S1201 that the power flag is not off, the process proceeds to S601. In this case, in S601, the network I/F status determination unit 311 detects the status of the second network I/F unit 218, i.e., the link up status or the link down status.
As described above, the processes from S601 onwards are substantially similar to the example shown in FIG.

As described above, in this embodiment, when MFP 122 starts a shutdown process, packets addressed to MFP 122 are discarded regardless of whether the shutdown process is completed. By applying such control, packets addressed to MFP 122 are discarded regardless of the shutdown timing of MFP 122. Therefore, it is possible to prevent the occurrence of a situation in which the above-mentioned packets are sent to the first network 101 and detected as suspicious packets.

<Other embodiments>
The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

In addition, various modifications may be made within the scope of the basic technical concept of the system according to this embodiment. As a specific example, in the above embodiment, the device to which the packet is to be sent is an MFP, but the device is not necessarily limited to an MFP, and other devices other than MFPs may be applied as long as they are devices to be managed. In addition, there is no particular limitation on the configuration of the DFE 121 (especially, the communication management module 310) that plays the role of the above-mentioned communication control. In other words, the subject of the above-mentioned communication control is not particularly limited as long as it is a device that is connected to the device to which the packet is to be sent via a network (equivalent to the second network 102) and is connected to another network (equivalent to the first network 101) different from the network.

The disclosure of the present embodiment also includes the following configurations, methods, and programs.
(Configuration 1) A communication control device having a first network interface connected to a first network and a second network interface connected to a device to be managed via a second network different from the first network, comprising: a control means for controlling packets received via the first network interface and addressed to the device to be sent to the device via the second network interface; and a first determination means for determining whether the state of the second network interface is link down, wherein the control means discards packets addressed to the device when the first determination means determines that the state of the second network interface is link down.
(Configuration 2) A communication control device as described in configuration 1, further comprising a second determination means for determining whether the device is in a sleep state or not, and the control means discards packets designated as destinations for the device when the second determination means determines that the device is in a sleep state, even if the first determination means determines that the state of the second network interface is not link down.
(Configuration 3) The communication control device described in configuration 2, characterized in that even if the second determination means determines that the device is in a sleep state, if a packet to be sent to the device is included in a packet list that returns the device from the sleep state, the control means controls the packet to be sent to the device.
(Configuration 4) A communication control device described in any one of configurations 1 to 3, further comprising a third judgment means for judging whether the power state of the device is off or not, and wherein the control means, when the third judgment means judges that the power state of the device is off, discards a packet for which the device is specified as the destination.
(Configuration 5) A communication control device described in any one of configurations 1 to 4, characterized in that the equipment is an image forming device that forms an image on a recording medium, and the communication control device is a communication management module provided in a printing control device connected to the image forming device via the second network interface.
(Method 1) A control method for a communication control device having a first network interface connected to a first network and a second network interface connected to a device to be managed via a second network different from the first network, comprising: a control step of controlling packets received via the first network interface and addressed to the device so that they are sent to the device via the second network interface; and a first determination step of determining whether the state of the second network interface is link down or not, wherein the control step is characterized in that when it is determined in the first determination step that the state of the second network interface is link down, the control step discards packets addressed to the device.
(Program 1) A program for causing a computer to function as a communication control device having a first network interface connected to a first network and a second network interface connected to a device to be managed via a second network different from the first network, the program having a control means for controlling packets received via the first network interface and addressed to the device to be sent to the device via the second network interface, and a first determination means for determining whether the state of the second network interface is link down, the program being characterized in that the control means discards packets addressed to the device when the first determination means determines that the state of the second network interface is link down.

122 DFE
217 First network I/F unit 218 Second network I/F unit 311 Network I/F state determination unit 312 Packet transmission unit

Claims (7)

A communication control device having a first network interface connected to a first network and a second network interface connected to a device to be managed via a second network different from the first network,
a control means for controlling a packet received via the first network interface and designated as a destination for the device to be transmitted to the device via the second network interface;
a first determination means for determining whether the state of the second network interface is a link-down state;
having
The communication control device according to claim 1, wherein the control means discards a packet designated as a destination by the device when the first determination means determines that the state of the second network interface is link down. a second determination means for determining whether the device is in a sleep state;
2. The communication control device according to claim 1, characterized in that the control means discards packets addressed to the device when the second determination means determines that the device is in a sleep state, even if the first determination means determines that the state of the second network interface is not link down. The communication control device according to claim 2, characterized in that the control means controls the packet to be sent to the device when the packet to be sent to the device is included in a packet list for waking the device from the sleep state, even if the second determination means determines that the device is in the sleep state. a third determination means for determining whether the power state of the device is off;
2. The communication control device according to claim 1, wherein the control means discards a packet addressed to the device when the third determination means determines that the power state of the device is off. the device is an image forming device that forms an image on a recording medium,
The communication control device according to claim 1 , wherein the communication control device is a communication management module provided in a print control device connected to the image forming device via the second network interface. A method for controlling a communication control device having a first network interface connected to a first network and a second network interface connected to a device to be managed via a second network different from the first network, comprising:
a control step of controlling a packet received via the first network interface and designated as a destination for the device to be transmitted to the device via the second network interface;
a first determination step of determining whether a state of the second network interface is a link down;
Including,
The control method for a communication control device, characterized in that the control step discards packets designated as a destination by the device when it is determined in the first determination step that the state of the second network interface is link down. Computer,
A communication control device having a first network interface connected to a first network and a second network interface connected to a device to be managed via a second network different from the first network,
a control means for controlling a packet received via the first network interface and designated as a destination for the device to be transmitted to the device via the second network interface;
a first determination means for determining whether the state of the second network interface is a link-down state;
and functioning as a communication control device having the
The program, wherein the control means discards a packet designated as a destination by the device when the first determination means determines that the state of the second network interface is link down.

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