In-vehicle relay device, in-vehicle monitoring device, in-vehicle network system, communication monitoring method, and recording medium

An in-vehicle monitoring device that is included in an in-vehicle network having a first control network and a second control network between which communication is relayed by a relay device and that is connected to the first control network, the in-vehicle monitoring device comprising:

• a communication circuit that receives control data transmitted from a control device connected to the first control network, the control data including, in a frame, a plurality of control commands for control to be performed by a control device connected to the second control network;
• and
• a processor that
• determines, as a first determination, whether control command types of the plurality of control commands included in the frame form a first combination, the first combination being preset as a combination of control commands that are consistent with one another to be executable simultaneously,
• determines, as a second determination, whether the control data is anomalous by using a result of the first determination, and
• outputs a result of the second determination,
• wherein largest data size of a control command transmittable in one frame in the first control network is larger than largest data size of a control command transmittable in one frame in the second control network.

A communication monitoring method for use of an in-vehicle relay device that relays communication between a plurality of control devices in a vehicle over a plurality of networks to which the plurality of control devices are connected, the in-vehicle relay device including a communication circuit and a processor, the method comprising:

• receiving, by the communication circuit, control data from a first control network included in the plurality of networks, the control data including, in a frame, a plurality of control commands to be executed by at least one of the control devices;
• determining, by the processor, a first determination as to whether control command types of the plurality of control commands included in the frame form a first combination, the first combination being preset as a combination of control commands that are consistent with one another to be executable simultaneously;
• determining, by the processor, a second determination as to whether the control data is anomalous by using a result of the first determination;
• and
• outputting, by the processor, a result of the second determination.

A non-transitory computer-readable recording medium storing a program for use in an in-vehicle relay device that relays communication between a plurality of control devices in a vehicle over a plurality of networks to which the plurality of control devices are connected, the in-vehicle relay device including a communication circuit and a processor, the program comprising a program code executing a method, when the program is executed by the processor, the method comprising:

• receiving, by the communication circuit, control data from a first control network included in the plurality of networks, the control data including, in a frame, a plurality of control commands to be executed by at least one of the control devices;
• determining, as a first determination, whether control command types of the plurality of control commands included in the frame form a first combination, the first combination being preset as a combination of control commands that are consistent with one another to be executable simultaneously;
• determining, as a second determination, whether the control data is anomalous by using a result of the first determination;
• and
• outputting a result of the second determination.

An in-vehicle network system comprising:

• a first control network and a second control network having a plurality of control devices connected thereto, that facilitate communication between the control devices being relayed by an in-vehicle relay device,
• wherein largest data size of a control command transmittable in one frame in the first control network is larger than largest data size of a control command transmittable in one frame in the second control network,
• wherein the control data transmitted from the first control network to the second control network includes, in one frame, a combination of a plurality of control commands that cause control devices connected to the second control network to perform predetermined control operations simultaneously, and
• wherein control types of the plurality of control commands included in the combination are consistent with one another to be executable simultaneously.