Abstract: A fraudulent transmission data detection device includes: a receiving unit that receives data that is transmitted in cycles; and plural determination units, each of which is configured to, based on whether or not a time from a reference timing until a predetermined number of data items are received by the receiving unit is less than a predetermined time, determine whether or not fraudulent transmission data is contained in the received data, and in which at least the reference timing, or the predetermined number of data items and the predetermined time, are different from those of the other determination units.

Abstract: A communication device includes: a first judging section that performs, on received data, a communication abnormality determination based on detection rules; and a setting section that compares a category of data, which the first judging section has determined to represent a communication abnormality during a current trip, with a category of data that the first judging section has determined to represent a communication abnormality during a previous trip, and set a first category of data that has been determined to represent a communication abnormality during each of n trips, wherein n?2, or a second category of data for which a frequency of having been determined to represent a communication abnormality during the n trips is greater than or equal to a predetermined value, to be a suppression target for which determination thereof as representing a communication abnormality by the first judging section is to be suppressed.

Abstract: A communication device includes: a first judging section that performs, on received data, a communication abnormality determination based on detection rules; and a setting section that compares a category of data, which the first judging section has determined to represent a communication abnormality during a current trip, with a category of data that the first judging section has determined to represent a communication abnormality during a previous trip, and set a first category of data that has been determined to represent a communication abnormality during each of n trips, wherein n?2, or a second category of data for which a frequency of having been determined to represent a communication abnormality during the n trips is greater than or equal to a predetermined value, to be a suppression target for which determination thereof as representing a communication abnormality by the first judging section is to be suppressed.

Abstract: A fraudulent transmission data detection device includes: a receiving unit that receives data that is transmitted in cycles; and plural determination units, each of which is configured to, based on whether or not a time from a reference timing until a predetermined number of data items are received by the receiving unit is less than a predetermined time, determine whether or not fraudulent transmission data is contained in the received data, and in which at least the reference timing, or the predetermined number of data items and the predetermined time, are different from those of the other determination units.

Abstract: A communication device is provided that readily increases the communication capacity of communication data based on a given protocol, without increasing the number of wired connections. The communication device sends and receives communication data through a communication line. A transmitting section sends a communication signal of modulated communication data to the communication line. A receiving section demodulates a communication signal received from the communication line to obtain communication data The transmitting section modulates the communication data on the basis of a frequency that varies dynamically within a predetermined transmission frequency band. The receiving section demodulates the received modulated communication signal corresponding to the transmission frequency band, to obtain the communication data.

Abstract: In a network system of this invention including a plurality of network devices that transfer frames by repeating, in a constant cycle, a reserved transfer interval that is a time band, in which a frame is transferred with a reservation and a free transfer interval that is a time band, in which a frame is freely transferred, a relay network device that links a first network device that is a transmission source of a frame and a second network device that is a transmission destination of the frame and the first network device execute a reservation processing such that the same time band within the reserved transfer interval is reserved and transfer the frame from the first network device to the second network device on the basis of the reservation result.

Abstract: A network device of is a network device that transfers frames by repeating, in a constant cycle, a reserved transfer interval and a free transfer interval. The network device includes a transmission port, a cycle timer, a mode switching control unit that monitors a transfer state of the transmission port and selects a store-and-forward system when the transmission port is in the transfer process and selects a cut-through system when the transmission port is not in the transfer process, and a transfer prohibition control unit that selects the cut-through system as a transfer system when a non-reserved frame is transmitted and switches a transfer method of the non-reserved frame to the store-and-forward system when a reserved transfer interval is established, with reference to the cycle timer.

Abstract: A network device that transfers frames by repeating, in a constant cycle, a reserved transfer interval that is a time band, in which a frame is transferred with a reservation, and a free transfer interval that is a time band, in which a frame is freely transferred, includes: a BPDU generation unit that generates a first BPDU; and a BPDU transmission instruction unit that instructs to arrange the first BPDU in the reserved transfer interval and transmit the first BPDU to a first other network device.

Abstract: In a network system of this invention including a plurality of network devices that transfer frames by repeating, in a constant cycle, a reserved transfer interval that is a time band, in which a frame is transferred with a reservation and a free transfer interval that is a time band, in which a frame is freely transferred, a relay network device that links a first network device that is a transmission source of a frame and a second network device that is a transmission destination of the frame and the first network device execute a reservation processing such that the same time band within the reserved transfer interval is reserved and transfer the frame from the first network device to the second network device on the basis of the reservation result.

Abstract: A network device of is a network device that transfers frames by repeating, in a constant cycle, a reserved transfer interval and a free transfer interval. The network device includes a transmission port, a cycle timer, a mode switching control unit that monitors a transfer state of the transmission port and selects a store-and-forward system when the transmission port is in the transfer process and selects a cut-through system when the transmission port is not in the transfer process, and a transfer prohibition control unit that selects the cut-through system as a transfer system when a non-reserved frame is transmitted and switches a transfer method of the non-reserved frame to the store-and-forward system when a reserved transfer interval is established, with reference to the cycle timer.