Patent Description:
In recent years, with the spread of the Internet of Things (IoT), various apparatuses (e.g., an IoT device) have been connected to the Internet. In some information processing systems including such apparatuses, an information processing apparatus is installed between an IoT device and a network to ensure confidentiality of a communication path on the network.

However, conventionally, one issue surrounding the information processing system has been its inability to continue communication between the devices when a problem occurs in the information processing apparatus.

[Patent Literature <NUM>] Jpn. KOKAI Publication No. <CIT>. Other prior art documents are <CIT>, <CIT> and <CIT>.

Preferred embodiments are defined in the independent claims.

Hereinafter, an information processing system according to an embodiment will be described with reference to the drawings.

<FIG> is a block diagram showing a configuration example of an information processing system <NUM> according to the embodiment.

As shown in <FIG>, the information processing system <NUM> includes information processing apparatuses <NUM> (<NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>,. ), IoT devices <NUM> (<NUM>-<NUM>, <NUM>-<NUM>,. ), a host device <NUM>, etc..

In the embodiment, all of the information processing apparatuses <NUM>-<NUM>, <NUM>-<NUM>, and <NUM>-<NUM> have the same configuration, and will be described as "the information processing apparatuses <NUM>" in instances which simply indicate the information processing apparatus included in the information processing system <NUM> or where no distinction between them need be made.

The IoT devices <NUM> and the host device <NUM> are endpoints that are terminal devices connected to a network NW2, and are examples of a terminal device <NUM>.

Each of the information processing apparatuses <NUM> is connected to the terminal apparatus <NUM>. The information processing apparatuses <NUM> are connected to the network NW2.

The network NW2 is a communication network for data transmission and reception between the host device <NUM> and the IoT devices <NUM>. That is, the network NW2 is a communication network that communicably connects the information processing apparatuses <NUM> to each other. For example, the network NW2 is an information communication network such as the Internet communication network or a local area network (LAN).

The IoT device <NUM> is a device that transmits and receives data to and from the host device <NUM> via the network NW2. The IoT device <NUM> is, for example, various devices connectable to the network NW2 such as an electric appliance, an automobile, a medical device, various sensors, a drone, or a POS terminal. The IoT device <NUM> may be a desktop PC, a notebook PC, a tablet PC, a smartphone, a wearable terminal, etc..

In the example shown in <FIG>, the IoT device <NUM>-<NUM> is connected to the network NW2 via the information processing apparatus <NUM>-<NUM>. The IoT device <NUM>-<NUM> is connected to the network NW2 via the information processing apparatus <NUM>-<NUM>.

The host device <NUM> controls the IoT devices <NUM>. The host device <NUM> is, for example, a computer device such as a server device or a personal computer (PC). In the example shown in <FIG>, the host device <NUM> is connected to the network NW2 via the information processing apparatus <NUM>-<NUM>.

The information processing apparatus <NUM> (a first information processing apparatus, a second information processing apparatus) is a communication control apparatus connected between the terminal device <NUM> and the network NW2. The information processing apparatus <NUM> relays data in communication between the terminal device <NUM> and the network NW2 while ensuring security. The information processing apparatus <NUM> encrypts data received from the terminal device <NUM>, and transmits the encrypted data to the network NW2. The information processing apparatus <NUM> also decrypts data received from the network NW2, and transmits the decrypted data to the terminal device <NUM>.

Next, the information processing apparatus <NUM> will be described.

<FIG> is a block diagram showing a configuration example of the information processing apparatus <NUM>. As shown in <FIG>, the information processing apparatus <NUM> includes a device interface <NUM>, a network interface <NUM>, a photo relay switch <NUM>, a storage part <NUM>, a control part <NUM>, a power supply part <NUM>, a battery <NUM>, etc..

The device interface <NUM> (a first device interface, a second device interface) is an interface for transmitting and receiving data to and from the terminal device <NUM>. The device interface <NUM> is connected to the terminal device <NUM> and communicates with the terminal device <NUM>. That is, the device interface <NUM> outputs data from the control part <NUM> to the terminal device <NUM>. The device interface <NUM> also outputs data from the terminal device <NUM> to the control part <NUM>. For example, the device interface <NUM> supports a LAN connection.

The network interface <NUM> (a first network interface, a second network interface) is an interface for transmitting and receiving data to and from the network NW2. The network interface <NUM> is connected to the network NW2. The network interface <NUM> communicates with other information processing apparatuses <NUM> via the network NW. That is, the network interface <NUM> outputs data from the control part <NUM> to the network NW2. The network interface <NUM> also outputs data from the network NW2 to the control part <NUM>. For example, the network interface <NUM> supports a LAN connection.

The photo relay switch <NUM> is connected between the device interface <NUM> and the network interface <NUM>. The photo relay switch <NUM> connects the device interface <NUM> and the network interface <NUM>. The photo relay switch <NUM> is a normally-closed switch. That is, the photo relay switch <NUM> connects the device interface <NUM> and the network interface <NUM> in a state where electric power is not supplied. The photo relay switch <NUM> disconnects the device interface <NUM> and the network interface <NUM> from each other in a state where electric power is supplied.

The photo relay switch <NUM> includes a photodiode therein. The photo relay switch <NUM> causes the photodiode to emit light, thereby bringing a communication line between the device interface <NUM> and the terminal device <NUM> and a communication line between the network interface <NUM> and the network NW2 into a conductive state.

The storage part <NUM> stores various types of data. For example, the storage part <NUM> functions as a ROM, a RAM, and a NVM. The storage part <NUM> stores a control program, control data, etc. The control program and the control data are incorporated in advance according to the specification of the information processing apparatus <NUM>. For example, the control program is a program that supports a function realized by the information processing apparatus <NUM>.

Further, the storage part <NUM> temporarily stores data being processed by the control part <NUM>. The storage part <NUM> may also store data necessary for execution of an application program, an execution result of an application program, etc..

The control part <NUM> (a first control part, a second control part) comprehensively controls the information processing apparatus <NUM>. The control part <NUM> relays communication between the terminal device <NUM> and the network NW2 by using the device interface <NUM> and the network interface <NUM>. That is, the control part <NUM> transmits data received from the terminal device <NUM> through the device interface <NUM> to the network NW2 through the network interface <NUM>. Further, the control part <NUM> transmits data received through the network interface <NUM> to the terminal device <NUM> through the device interface <NUM>.

For example, the control part <NUM> is a processor that executes a control program stored in the storage part <NUM>, etc. The control part <NUM> may include an application specific integrated circuit (ASIC) or a field-programmable gate array (FPGA).

The power supply part <NUM> supplies electric power to each part of the information processing apparatus <NUM> using electric power from an external power supply. For example, the power supply part <NUM> converts an AC voltage from a commercial power supply into a DC voltage of a predetermined voltage, and supplies the DC voltage to each part.

The battery <NUM> is a battery that supplies electric power to each part of the information processing apparatus <NUM>. The battery <NUM> supplies electric power to each part when the power supply part <NUM> stops supplying electric power. The battery <NUM> may supply electric power to each part based on control from the control part <NUM>. The battery <NUM> may also automatically supply electric power to each part when the power supply part <NUM> stops supplying electric power. For example, the battery <NUM> is a primary battery or a secondary battery. Further, the battery <NUM> may be a capacitor, etc..

Next, the host device <NUM> will be described. <FIG> is a block diagram showing a configuration example of the host device <NUM>. As shown in <FIG>, the host device <NUM> includes a processor <NUM>, a ROM <NUM>, a RAM <NUM>, a NVM <NUM>, a communication part <NUM>, an operation part <NUM>, a display part <NUM>, etc. These parts are connected to one another via a data bus, etc..

The processor <NUM> has a function of controlling an overall operation of the host device <NUM>. The processor <NUM> may include an internal cache, various interfaces, etc. The processor <NUM> realizes various processing by executing programs stored in advance in an internal memory, the ROM <NUM>, or the NVM <NUM>.

Note that some of the various functions realized by the execution of programs by the processor <NUM> may also be realized by a hardware circuit. In this case, the processor <NUM> controls a function performed by the hardware circuit.

The ROM <NUM> is a non-volatile memory in which a control program, control data, etc. are stored in advance. The control program and control data stored in the ROM <NUM> are incorporated in advance according to the specification of the host device <NUM>. The ROM <NUM> stores, for example, a program for controlling a circuit board of the host device <NUM>.

The RAM <NUM> is a volatile memory. The RAM <NUM> temporarily stores data being processed by the processor <NUM>. The RAM <NUM> stores various application programs based on instructions from the processor <NUM>. In addition, the RAM <NUM> may store data necessary for executing the application programs, execution results of the application programs, etc..

The NVM <NUM> is a non-volatile memory capable of writing and rewriting data. The NVM <NUM> includes, for example, a hard disk drive (HDD), a solid state drive (SSD), or a flash memory. The NVM <NUM> stores control programs, applications, various types of data, etc. according to the operational use of the host device <NUM>.

The communication part <NUM> is an interface for transmitting and receiving data to and from the information processing apparatus <NUM> (e.g., the information processing apparatus <NUM>-<NUM>). The communication part <NUM> is connected to the information processing apparatus <NUM>. The communication part <NUM> outputs to the information processing apparatus <NUM> data transmitted from the host device <NUM> to the IoT device <NUM>. The communication part <NUM> also outputs data from the information processing apparatus <NUM> to the processor <NUM>. For example, the communication part <NUM> supports a LAN connection.

The operation part <NUM> receives inputs of various operations from an operator. The operation part <NUM> transmits a signal indicating a received operation to the processor <NUM>. For example, the operation part <NUM> includes a keyboard, a ten key, and a touch panel.

The display part <NUM> displays various types of information based on control of the processor <NUM>. For example, the display part <NUM> is constituted by a liquid crystal monitor. When the operation part <NUM> is constituted by a touch panel, etc., the display part <NUM> may be formed integrally with the operation part <NUM>.

Next, functions realized by the information processing apparatus <NUM> will be described. The functions realized by the information processing apparatus <NUM> are realized by the control part <NUM>.

First, the control part <NUM> has a function of relaying communication between the terminal device <NUM> and the network NW2.

The control part <NUM> receives data addressed to a predetermined terminal device <NUM> from the terminal device <NUM> through the device interface <NUM>. When the data is received from the terminal device <NUM>, the control part <NUM> encrypts the received data (a first conversion process, an encryption process). For example, the control part <NUM> may encrypt the data using a common key shared with another information processing apparatus <NUM>. The control part <NUM> may also encrypt the data using a public key acquired from another information processing apparatus <NUM>.

When the data is encrypted, the control part <NUM> transmits the encrypted data to the network NW2 through the network interface <NUM>.

Further, the control part <NUM> receives encrypted data from another information processing apparatus <NUM> through the network interface <NUM>. When the encrypted data is received, the control part <NUM> decrypts the received data (a second conversion process corresponding to the first conversion process). For example, the control part <NUM> may decrypt the data using a common key shared with another information processing apparatus <NUM>. In addition, the control part <NUM> may decrypt the data using a secret key.

When the data is decrypted, the control part <NUM> transmits the decrypted data to the terminal device <NUM> through the device interface <NUM>.

Further, the control part <NUM> stores a communication log in the storage part <NUM>. The control part <NUM> stores, in the storage part <NUM>, for example, a communication date and time, a data amount, a transmission source, a port of the transmission source, a destination, a port of the destination, or various environmental parameters, as the communication log. The configuration of the communication log is not limited to a specific configuration.

In addition, the control part <NUM> stores a self-diagnosis log in the storage part <NUM>. For example, the control part <NUM> performs self-diagnosis of an internal element (such as an IC) at the time of activation or at predetermined intervals. When the self-diagnosis is performed, the control part <NUM> stores a self-diagnosis log indicating the content of the self-diagnosis in the storage part <NUM>.

The control part <NUM> supplies electric power to the photo relay switch <NUM> to keep the photo relay switch <NUM> off.

Further, the control part <NUM> has a function of determining whether the power supply part <NUM> supplies electric power.

For example, the power supply part <NUM> stops the power supply when a power supply from an external power supply is stopped or when a failure occurs in the power supply part <NUM>. The control part <NUM> may also determine whether the power supply part <NUM> supplies electric power based on a signal from the power supply part <NUM>. In addition, the control part <NUM> may determine whether the power supply part <NUM> supplies electric power based on a voltage output from the power supply part <NUM>. For example, if the voltage output from the power supply part <NUM> is equal to or higher than a predetermined threshold value, the control part <NUM> determines that the power supply part <NUM> supplies electric power. If the voltage output from the power supply part <NUM> is lower than the predetermined threshold, the control part <NUM> determines that the power supply part <NUM> stops supplying electric power.

If it is determined that the power supply by the power supply part <NUM> is stopped, the control part <NUM> may transmit an instruction to the battery <NUM> to supply electric power to each part. In addition, if it is determined that the power supply by the power supply part <NUM> is stopped, the control part <NUM> may perform self-diagnosis.

If it is determined that the power supply by the power supply part <NUM> is stopped, the control part <NUM> may transmit a communication log and a self-diagnosis log to the host device <NUM>.

In addition, the control part <NUM> has a function of transmitting, to the host device <NUM>, a message (a third message) indicating that the power supply source is switched from the power supply part <NUM> to the battery <NUM> if it is determined that the power supply by the power supply part <NUM> is stopped.

Here, it is assumed that the information processing apparatus <NUM> is connected to the IoT device <NUM>.

The control part <NUM> generates the message indicating that the power supply source is switched from the power supply part <NUM> to the battery <NUM>. When the message is generated, the control part <NUM> encrypts the message. When the message is encrypted, the control part <NUM> transmits the encrypted message to the information processing apparatus <NUM>-<NUM> through the network interface <NUM>.

In addition, the control part <NUM> has a function of transmitting, to the host device <NUM>, a message (a second message) indicating that an energy saving mode is set when the remaining capacity of the battery <NUM> becomes equal to or less than a predetermined threshold value (an energy saving transition threshold value, a second threshold value). Here, the energy saving transition threshold value is greater than a pass-through transition threshold value to be described later.

The control part <NUM> acquires the remaining capacity of the battery <NUM>. The control part <NUM> may measure a voltage output from the battery <NUM> to acquire the remaining capacity. The control part <NUM> may acquire the remaining capacity based on a signal from a sensor for measuring the remaining capacity of the battery <NUM>.

The control part <NUM> determines whether the remaining capacity of the battery <NUM> is equal to or less than the energy saving transition threshold value at predetermined intervals. If it is determined that the remaining capacity of the battery <NUM> is equal to or less than the energy saving transition threshold value, the control part <NUM> generates a message indicating that the energy saving mode is set.

When the message is generated, the control part <NUM> encrypts the message. When the message is encrypted, the control part <NUM> transmits the encrypted message to the information processing apparatus <NUM>-<NUM> through the network interface <NUM>.

If it is determined that the remaining capacity of the battery <NUM> is equal to or less than the energy saving transition threshold value, the control part <NUM> may transmit a communication log and a self-diagnosis log to the host device <NUM>.

The energy saving mode will be described later.

Further, the control part <NUM> has a function of setting the energy saving mode when the remaining capacity of the battery <NUM> becomes equal to or less than the energy saving transition threshold value.

When the message indicating that the energy saving mode is set is transmitted to the host device <NUM>, the control part <NUM> sets the energy saving mode.

The energy saving mode is an operation mode for saving electric power consumed by the operation of the information processing apparatus <NUM>.

When the energy saving mode is set, the control part <NUM> does not perform an encryption process on data from the terminal device <NUM>. Here, the control part <NUM> adds an identifier to data from the terminal device <NUM> and transmits the data to the network NW2. For example, the identifier is a value for detecting falsification of data. The control part <NUM> calculates an identifier based on data from the terminal device <NUM> and adds the identifier to the data.

In addition, the control part <NUM> may not perform a decryption process of data from the network NW2. Further, the control part <NUM> may check the identifier added to the data.

The control part <NUM> may not store a communication log in the storage part <NUM>. The control part <NUM> may turn off an LED, etc. incorporated into the housing of the information processing apparatus <NUM>. The operation when the control part <NUM> sets the energy saving mode is not limited to a specific configuration.

In addition, the control part <NUM> has a function of transmitting, to the host device <NUM>, a message (a first message) indicating that a pass-through mode is set when the remaining capacity of the battery <NUM> becomes equal to or less than a predetermined threshold value (a pass-through transition threshold value, a first threshold value) smaller than the energy saving transition threshold value.

The control part <NUM> acquires the remaining capacity of the battery <NUM>. The control part <NUM> determines whether the remaining capacity of the battery <NUM> is equal to or less than the pass-through transition threshold value at predetermined intervals. If it is determined that the remaining capacity of the battery <NUM> is equal to or less than the pass-through transition threshold value, the control part <NUM> generates a message indicating that the pass-through mode is set.

When the message is generated, the control part <NUM> adds an identifier to the message. When the identifier is added to the message, the control part <NUM> transmits the message to which the identifier is added to the information processing apparatus <NUM>-<NUM> through the network interface <NUM>.

If it is determined that the remaining capacity of the battery <NUM> is equal to or less than the pass-through transition threshold value, the control part <NUM> may transmit a communication log and a self-diagnosis log to the host device <NUM>.

The pass-through mode will be described later.

Further, the control part <NUM> has a function of setting the pass-through mode when the remaining capacity of the battery <NUM> becomes equal to or less than the pass-through transition threshold value.

When the message indicating that the pass-through mode is set is transmitted to the host device <NUM>, the control part <NUM> sets the pass-through mode.

The pass-through mode is an operation mode in which the terminal device <NUM> and the network NW2 are directly connected to each other. That is, the pass-through mode is an operation mode in which data between the network NW2 and the terminal device <NUM> is relayed without being encrypted or decrypted.

When the pass-through mode is set, the control part <NUM> stops the power supply to the photo relay switch <NUM>. As a result, the photo relay switch <NUM> connects the device interface <NUM> and the network interface <NUM>. That is, the photo relay switch <NUM> connects the terminal device <NUM> and the network NW2.

When the power supply to the photo relay switch <NUM> is stopped, the control part <NUM> may turn off the power of the information processing apparatus <NUM>.

The control part <NUM> has a function of transmitting data from the network NW2 to the host device <NUM> without decrypting the data in accordance with control of the host device <NUM>.

Here, it is assumed that the information processing apparatus <NUM> is connected to the host device <NUM>.

The control part <NUM> receives a command indicating that a predetermined information processing apparatus <NUM> (e.g., the information processing apparatus <NUM>-<NUM>) is operating in the energy saving mode from the host device <NUM>. That is, the control part <NUM> receives a command instructing non-decryption of data received from the information processing apparatus <NUM>. When the command is received, the control part <NUM> checks an identifier of the data without decrypting the data from the predetermined information processing apparatus <NUM>.

When the identifier of the data is checked, the control part <NUM> transmits the data to the host device <NUM> through the device interface <NUM>. When the identifier does not match, the control part <NUM> may transmit information indicating that the identifier does not match to the host device <NUM>.

In addition, the control part <NUM> receives a command indicating that a predetermined information processing apparatus <NUM> (e.g., the information processing apparatus <NUM>-<NUM>) is operating in the pass-through mode from the host device <NUM>. That is, the control part <NUM> receives a command instructing non-decryption of data received from the information processing apparatus <NUM>. When the command is received, the control part <NUM> transmits the data from the predetermined information processing apparatus <NUM> to the host device <NUM> through the device interface <NUM> without decrypting the data.

Next, functions realized by the host device <NUM> will be described. The functions realized by the host device <NUM> are realized by the processor <NUM> executing programs stored in the ROM <NUM>, NVM <NUM>, etc..

First, the processor <NUM> has a function of outputting a warning when receiving a message indicating that the power supply source is switched from the power supply part <NUM> to the battery <NUM>.

For example, the processor <NUM> receives a message indicating that the power supply source is switched from the power supply part <NUM> to the battery <NUM> from a predetermined information processing apparatus <NUM> through the communication part <NUM>. When the message is received, the processor <NUM> displays, on the display part <NUM>, a warning indicating that the predetermined information processing apparatus <NUM> is operating by the battery <NUM>, etc..

The processor <NUM> has a function of outputting a warning when receiving a message indicating that the energy saving mode is set.

For example, the processor <NUM> receives a message indicating that the energy saving mode is set from the information processing apparatus <NUM> through the communication part <NUM>. When the message is received, the processor <NUM> displays, on the display part <NUM>, a warning indicating that the information processing apparatus <NUM> is operating in the energy saving mode, etc..

In addition, the processor <NUM> has a function of transmitting a command, indicating that the information processing apparatus <NUM> transmitting the message is operating in the energy saving mode, to an information processing apparatus <NUM> connected to the processor <NUM> when the message indicating that the energy saving mode is set is received.

Here, it is assumed that the processor <NUM> receives the message from the information processing apparatus <NUM> (e.g., the information processing apparatus <NUM>-<NUM>) connected to the IoT device <NUM>. When the message is received, the processor <NUM> transmits a command indicating that the information processing apparatus <NUM> is operating in the energy saving mode to the information processing apparatus <NUM>-<NUM> through the communication part <NUM>. That is, the control part <NUM> transmits, to the information processing apparatus <NUM>-<NUM>, a command instructing non-decryption of data received from the information processing apparatus <NUM>.

In addition, the processor <NUM> has a function of outputting a warning when receiving a message indicating that the pass-through mode is set.

For example, the processor <NUM> receives the message indicating that the pass-through mode is set from the information processing apparatus <NUM> through the communication part <NUM>. When the message is received, the processor <NUM> displays, on the display part <NUM>, a warning indicating that the information processing apparatus <NUM> is operating in the pass-through mode, etc..

In addition, the processor <NUM> has a function of transmitting a command, indicating that the information processing apparatus <NUM> transmitting the message is operating in the pass-through mode, to an information processing apparatus <NUM> connected to the processor <NUM> when the message indicating that the pass-through mode is set is received.

Here, it is assumed that the processor <NUM> receives the message from the information processing apparatus <NUM> (e.g., the information processing apparatus <NUM>-<NUM>) connected to the IoT device <NUM>. When the message is received, the processor <NUM> transmits a command, indicating that the information processing apparatus <NUM> is operating in the pass-through mode, to the information processing apparatus <NUM>-<NUM> through the communication part <NUM>. That is, the control part <NUM> transmits, to the information processing apparatus <NUM>-<NUM>, a command instructing non-decryption of data received from the information processing apparatus <NUM>.

Next, an operation example of the information processing apparatus <NUM> will be described. Here, an operation example in which the information processing apparatus <NUM> changes an operation mode will be described.

<FIG> is a flowchart for explaining an operation example in which the information processing apparatus <NUM> changes an operation mode.

First, the control part <NUM> of the information processing apparatus <NUM> determines whether the power supply part <NUM> supplies electric power (S11). If it is determined that the power supply part <NUM> supplies electric power (S11, YES), the control part <NUM> executes a normal routine (S12). When the normal routine is executed, the control part <NUM> returns to S11.

If it is determined that the power supply part <NUM> stops supplying electric power (S11, NO), the control part <NUM> transmits, to the host device <NUM>, a message indicating that the power supply source is switched from the power supply part <NUM> to the battery <NUM> (S13). Here, the battery <NUM> supplies electric power to each part.

When the message indicating the switching of the power supply source from the power supply part <NUM> to the battery <NUM> is transmitted, the control part <NUM> determines whether the remaining capacity of the battery <NUM> is equal to or less than an energy saving transition threshold value (S14). If it is determined that the remaining capacity of the battery <NUM> exceeds the energy saving transition threshold value (S14, NO), the control part <NUM> executes a normal routine (S15). When the normal routine is executed, the control part <NUM> returns to S14.

If it is determined that the remaining capacity of the battery <NUM> is equal to or less than the energy saving transition threshold value (S14, YES), the control part <NUM> transmits, to the host device <NUM>, a message indicating that an energy saving mode is set (S16).

When the message indicating that the energy saving mode is set is transmitted, the control part <NUM> determines whether the remaining capacity of the battery <NUM> is equal to or less than a pass-through transition threshold value (S17). If it is determined that the remaining capacity of the battery <NUM> exceeds the pass-through transition threshold value (S17, NO), the control part <NUM> executes an energy saving routine (S18). When the energy saving routine is executed, the control part <NUM> returns to S17.

If it is determined that the remaining capacity of the battery <NUM> is equal to or less than the pass-through transition threshold value (S17, YES), the control part <NUM> transmits, to the host device <NUM>, a message indicating that a pass-through mode is set (S19).

When the message indicating that the pass-through mode is set is transmitted, the control part <NUM> sets the pass-through mode (S20). When the pass-through mode is set, the control part <NUM> turns off its own power (S21). When its own power is turned off, the control part <NUM> ends the operation.

Next, an operation example in which the control part <NUM> executes the normal routines (S12 and S15) will be described. <FIG> is a flowchart for explaining an operation example in which the control part <NUM> executes the normal routines (S12 and S15).

First, the control part <NUM> determines whether data is received from the terminal device <NUM> through the device interface <NUM> (S31). If it is determined that the data is received from the terminal device <NUM> (S31, YES), the control part <NUM> encrypts the data (S32). When the data is encrypted, the control part <NUM> transmits the encrypted data to the network NW2 through the network interface <NUM> (S33).

When the encrypted data is transmitted to the network NW2, the control part <NUM> stores a communication log in the storage part <NUM> (S34).

If it is determined that the data is not received from the terminal device <NUM> (S31, NO) or if the communication log is stored in the storage part <NUM> (S34), the control part <NUM> determines whether data is received from the network NW2 through the network interface <NUM> (S35). If it is determined that the data is received from the network NW2 (S35, YES), the control part <NUM> decrypts the data (S36). When the data is decrypted, the control part <NUM> transmits the decrypted data to the terminal device <NUM> through the device interface <NUM> (S37).

When the decrypted data is transmitted to the terminal device <NUM>, the control part <NUM> stores a communication log in the storage part <NUM> (S38). If it is determined that the data is not received from the network NW2 (S35, NO) or if the communication log is stored in the storage part <NUM> (S38), the control part <NUM> ends the operation.

Next, an operation example in which the control part <NUM> executes the energy saving routine (S18) will be described. <FIG> is a flowchart for explaining an operation example in which the control part <NUM> executes the energy saving routine (S18).

First, the control part <NUM> determines whether data is received from the terminal device <NUM> through the device interface <NUM> (S41). If it is determined that the data is received from the terminal device <NUM> (S41, YES), the control part <NUM> adds an identifier to the data (S42). When the identifier is added to the data, the control part <NUM> transmits the data to which the identifier is added to the network NW2 through the network interface <NUM> (S43).

If it is determined that the data is not received from the terminal device <NUM> (S41, NO) or if the data to which the identifier is added is transmitted to the network NW2 (S43), the control part <NUM> determines whether data is received from the network NW2 through the network interface <NUM> (S44).

If it is determined that the data is received from the network NW2 (S44, YES), the control part <NUM> checks an identifier of the data (S45). When the identifier of the data is checked, the control part <NUM> transmits the data to the terminal device <NUM> through the device interface <NUM> (S46).

If it is determined that the data is not received from the network NW2 (S44, NO) or if the data is transmitted to the terminal device <NUM> (S46), the control part <NUM> ends the operation.

When there is a mismatch in the identifier in S45, the control part <NUM> may transmit information indicating such a mismatch in the data to the terminal device <NUM>. In addition, when there is a mismatch in the identifier in S45, the control part <NUM> need not transmit the data to the terminal device <NUM>.

Next, an operation example of the host device <NUM> will be described. <FIG> is a flowchart for explaining an operation example of the host device <NUM>.

First, the processor <NUM> of the host device <NUM> determines whether a message is received from the information processing apparatus <NUM> connected to the IoT device <NUM> through the communication part <NUM> (S51). If it is determined that the message is not received from the information processing apparatus <NUM> (S51, NO), the processor <NUM> returns to S51.

If it is determined that the message is received from the information processing apparatus <NUM> (S51, YES), the processor <NUM> determines whether the received message is a message indicating that the power supply source is switched from the power supply part <NUM> to the battery <NUM> (S52).

If it is determined that the received message is a message indicating that the power supply source is switched from the power supply part <NUM> to the battery <NUM> (S52, YES), the processor <NUM> displays a warning indicating that the information processing apparatus <NUM> that is the transmission source of the message is operating by the battery <NUM> on the display part <NUM> (S53).

If it is determined that the received message is not a message indicating that the power supply source is switched from the power supply part <NUM> to the battery <NUM> (S52, NO), the processor <NUM> determines whether the received message is a message indicating that an energy saving mode is set (S54).

If it is determined that the received message is a message indicating that the energy saving mode is set (S54, YES), the processor <NUM> displays a warning indicating that the information processing apparatus <NUM> that is the transmission source of the message is operating in the energy saving mode on the display part <NUM> (S55).

When the warning is displayed, the processor <NUM> transmits, to an information processing apparatus <NUM> (the information processing apparatus <NUM>-<NUM>) connected to the processor <NUM>, a command indicating that the information processing apparatus <NUM> that is the transmission source of the message is operating in the energy saving mode (S56).

If it is determined that the received message is not a message indicating that the energy saving mode is set (S54, NO), the processor <NUM> determines whether the received message is a message indicating that a pass-through mode is set (S57).

If it is determined that the received message is a message indicating that the pass-through mode is set (S57, YES), the processor <NUM> displays a warning indicating that the information processing apparatus <NUM> that is the transmission source of the message is operating in the pass-through mode on the display part <NUM> (S58).

When the warning is displayed, the processor <NUM> transmits, to the information processing apparatus <NUM> (the information processing apparatus <NUM>-<NUM>) connected to the processor <NUM>, a command indicating that the information processing apparatus <NUM> that is the transmission source of the message is operating in the pass-through mode (S59).

If it is determined that the received message is not a message indicating that the pass-through mode is set (S57, NO), the processor <NUM> performs other processing according to the message (S60).

When the warning is displayed (S53), when the command is transmitted (S56), when the command is transmitted (S59), or when other processing is performed (S60), the processor <NUM> ends the operation.

The control part <NUM> of the information processing apparatus <NUM> may sequentially or simultaneously perform the operations of transmitting the message indicating that the pass-through mode is set and setting the pass-through mode. In addition, the control part <NUM> of the information processing apparatus <NUM> may transmit the message indicating that the pass-through mode is set after setting the pass-through mode.

Further, the control part <NUM> of the information processing apparatus <NUM> may sequentially or simultaneously perform the operations of transmitting the message indicating that the energy saving mode is set and the setting the energy saving mode. The control part <NUM> of the information processing apparatus <NUM> may transmit the message indicating that the energy saving mode is set after setting the energy saving mode.

The control part <NUM> of the information processing apparatus <NUM> may set the energy saving mode at the time when the power supply from the power supply part <NUM> is stopped. In this case, the control part <NUM> transmits, to the host device <NUM>, the message indicating that the energy saving mode is set at the time when the power supply from the power supply part <NUM> is stopped.

Further, the control part <NUM> of the information processing apparatus <NUM> may set the pass-through mode at the time when the power supply from the power supply part <NUM> is stopped. In this case, the control part <NUM> transmits, to the host device <NUM>, the message indicating that the pass-through mode is set at the time when the power supply from the power supply part <NUM> is stopped.

The control part <NUM> of the information processing apparatus <NUM> may transmit the message indicating that the energy saving mode is set to another information processing apparatus <NUM>. When the message is received, the control part <NUM> of said another information processing apparatus <NUM> transmits data from the information processing apparatus <NUM> that is the transmission source of the message to the terminal device <NUM> without decrypting the data (e.g., by removing the identifier).

The control part <NUM> of the information processing apparatus <NUM> may transmit the message indicating that the pass-through mode is set to another information processing apparatus <NUM>. When the message is received, the control part <NUM> of said another information processing apparatus <NUM> transmits data from the information processing apparatus <NUM> that is the transmission source of the message to the terminal device <NUM> without decrypting the data.

The control part <NUM> of the information processing apparatus <NUM> may not encrypt data from the terminal device <NUM>. For example, the control part <NUM> may compress the data, and transmit it to the network NW2. In this case, the control part <NUM> decompresses data from the network NW2 and transmits the decompressed data to the terminal device <NUM>.

The information processing apparatus formed as described above notifies the host device that the energy saving mode or the pass-through mode is set when electric power cannot be supplied to each part by external power. As a result, the host device instructs an information processing apparatus connected thereto to relay data from the information processing apparatus operating in the energy saving mode or the pass-through mode without decrypting the data. Thus, the host device can appropriately acquire the data from the information processing apparatus operating in the energy saving mode or the pass-through mode. Therefore, the information processing system can continue communication between the terminal devices even when a trouble occurs in the information processing apparatus.

Claim 1:
An information processing system (<NUM>) comprising a host device (<NUM>), a first information processing apparatus (<NUM>), and a second information processing apparatus (<NUM>), wherein the first information processing apparatus (<NUM>) comprises:
a first device interface (<NUM>) configured to transmit and receive data to and from a terminal device (<NUM>);
a first network interface (<NUM>) configured to transmit and receive data to and from a network (NW2);
a power supply part (<NUM>) configured to supply electric power from an external power supply;
a battery (<NUM>) configured to supply electric power when a power supply from the power supply part (<NUM>) is stopped; and
a first control part (<NUM>) configured to:
perform a first conversion process on data from the terminal device (<NUM>), and transmit the data to the network (NW2); and
when the power supply from the power supply part (<NUM>) is stopped, transmit, to the host device (<NUM>) through the first network interface (<NUM>), a first message indicating that a pass-through mode in which data is relayed between the terminal device (<NUM>) and the network (NW2) without being subjected to the first conversion process is set, and set the pass-through mode,
wherein the second information processing apparatus (<NUM>) comprises:
a second device interface (<NUM>) configured to transmit and receive data to and from the host device (<NUM>);
a second network interface (<NUM>) configured to transmit and receive data to and from the terminal device (<NUM>) through the network (NW2); and
a second control part (<NUM>) configured to:
perform a second conversion process corresponding to the first conversion process on data from the first information processing apparatus (<NUM>), and transmit the data to the host device (<NUM>); and
when a command indicating that the first information processing apparatus (<NUM>) is operating in the pass-through mode, transmit the data from the first information processing apparatus (<NUM>) to the host device (<NUM>) without performing the second conversion process, and
wherein the host device (<NUM>) includes:
a communication part (<NUM>) configured to transmit and receive data to and from the second information processing apparatus (<NUM>); and
a processor (<NUM>) configured to transmit the command to the second information processing apparatus (<NUM>) through the communication part, and output a warning, when the first message is received through the communication part.