# US 2021/0243071 A1 · Control system and control method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0243071 A1 - Document ID: US20210243071A1 - Status: Published application - Kind: A1 - Application number: 17/137,091 - Filed: 2020-12-29 - Published: 2021-08-05 - Earliest claimed: 2020-01-31 - Assignees: Hitachi, Ltd. - Applicants: Hitachi, Ltd. - Inventors: Hidehiro KAWAI; Hideki OSONOI; Hidenori OMIYA - Web page: https://patentgrep.com/patent/US20210243071A1 ## CPC - H04L 43/0817: by checking functioning - H04L 12/40176: {involving redundancy (error detection or correction of the data by redundancy in hardware using active fault-masking in interconnections G06F11/2002; error detection or correction of the data by redundancy in hardware using active fault-masking in storage systems using spares or by reconfiguring G06F11/2053)} - H04L 12/462: {LAN interconnection over a bridge based backbone} - H04L 41/0631: using root cause analysis; using analysis of correlation between notifications, alarms or events based on decision criteria, e.g. hierarchy, tree or time analysis - H04L 41/0654: using network fault recovery (ring fault isolation or reconfiguration in loop networks without recovery actions by a network management system H04L12/437) - H04L 41/0659: by isolating or reconfiguring faulty entities - H04L 43/0811: by checking connectivity - H04L 43/16: Threshold monitoring - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A route failure and a device failure are detected in a short time without erroneous recognition. A multiplexing system includes: a first system having a pair of processing devices forming a pair; a second system having a pair of processing devices forming a pair that are different from the first system; each processing device of the first system and the second system includes a survival monitoring unit configured to monitor a failure of the each processing device or the each LAN based on a device time-out for confirming survival of the each processing device and a route time-out for confirming survival of the each LAN set to be longer than the device time-out. ## Claims ### Claim 1 A control system of a multiplexing system, the multiplexing system including: a first system having a pair of processing devices forming a pair; a second system having a pair of processing devices forming a pair that are different from the first system; a first inter-pair LAN directly connecting the pair of processing devices of the first system; a second inter-pair LAN directly connecting the pair of processing devices of the second system; a first inter-system LAN directly connecting one processing device of the pair of processing devices of the first system and one processing device of the pair of processing devices of the second system; a second inter-system LAN directly connecting another processing device of the pair of processing devices of the first system and another processing device of the pair of processing devices of the second system; an internal LAN connected to receive a processing result from a computing node provided on an internal side of the multiplexing system and perform a predetermined processing and connecting each pair of processing devices of the first system and the second system; and an external LAN connected to transmit the processing result from the computing node to a predetermined terminal provided on an external side of the multiplexing system and connecting each pair of processing devices of the first system and the second system, wherein each processing device of the first system and the second system includes a survival monitoring unit configured to monitor a failure of the each processing device or the each LAN based on a device time-out for confirming survival of the each processing device and a route time-out for confirming survival of the each LAN set to be longer than the device time-out. ### Claim 2 (depends on 1) The control system according to claim 1, wherein the each processing device of the first system and the second system includes a survival information reception unit configured to receive survival information including a survival time of an own device for determining the device time-out or the route time-out from the other processing device, and update a survival time of the other processing device or the each LAN included in the received survival information to a latest value, and the survival monitoring unit transmits the survival information including the survival time of the own device to the each processing device via the corresponding LAN, and determines occurrence of a failure by not updating the survival time of the other processing device or the each LAN included in the survival information received by the survival information reception unit to the latest value. ### Claim 3 (depends on 2) The control system according to claim 2, wherein the processing devices directly connected via the first inter-system LAN in the first system and the second system each include a first failure detection unit configured to detect a link-down of the first inter-system LAN, the processing devices directly connected via the second inter-system LAN in the first system and the second system each include a second failure detection unit configured to detect a link-down of the second inter-system LAN, and a multiplexing system control unit, which is configured to determine whether the survival information reception unit receives survival information of the processing device of the other system via a LAN other than a LAN in which the link-down is detected during a time period when the link-down is detected by the first failure detection unit or the second failure detection unit, determine that, when it is determined that the survival information is not received via the LAN other than the LAN in which the link-down is detected during the time period, the processing device of the other system is in a power-off state, and switch the system, is included. ### Claim 4 (depends on 2) The control system according to claim 2, wherein the survival monitoring unit transmits the survival information to the each processing device via the corresponding LAN based on a value obtained by adding an offset indicating a time difference for transmitting the survival information at different timings to the survival time of the own device. ### Claim 5 A control method performed in a control system of a multiplexing system, the control method comprising: in each processing device of a first system having a pair of processing devices forming a pair and a second system having a pair of processing devices forming a pair that are different from the first system in the multiplexing system, monitoring, by a survival monitoring unit, a failure of the each processing device or a LAN based on a device time-out for confirming survival of the each processing device and a route time-out for confirming survival of the each LAN set to be longer than the device time-out via any one of a first inter-pair LAN directly connecting the pair of processing devices of the first system, a second inter-pair LAN directly connecting the pair of processing devices of the second system, a first inter-system LAN directly connecting one processing device of the pair of processing devices of the first system and one processing device of the pair of processing devices of the second system, a second inter-system LAN directly connecting another processing device of the pair of processing devices of the first system and another processing device of the pair of processing devices of the second system, an internal LAN connected to receive a processing result from a computing node provided on an internal side of the multiplexing system and perform a predetermined processing and connecting each pair of processing devices of the first system and the second system, and an external LAN connected to transmit the processing result from the computing node to a predetermined terminal provided on an external side of the multiplexing system and connecting each pair of processing devices of the first system and the second system. ### Claim 6 (depends on 5) The control method according to claim 5, further comprising: in the each processing device of the first system and the second system, transmitting survival information including a survival time of an own device for determining the device time-out or the route time-out to the each processing device via the each LAN by the survival monitoring unit; receiving the survival information including the survival time of the own device from the other processing device by a survival information reception unit; updating a survival time of the other processing device or the each LAN included in the received survival information to a latest value by the survival information reception unit; and determining occurrence of a failure by not updating the survival time of the other processing device or the each LAN included in the survival information received by the survival information reception unit to the latest value by the survival monitoring unit. ### Claim 7 (depends on 6) The control method according to claim 6, further comprising: detecting a link-down of the first inter-system LAN by a first failure detection unit in respective processing devices directly connected via the first inter-system LAN in the first system and the second system; detecting a link-down of the second inter-system LAN by the second failure detection unit in respective processing devices directly connected via the second inter-system LAN in the first system and the second system; determining, by a multiplexing system control unit, whether the survival information reception unit receives survival information of the processing device of the other system via a LAN other than a LAN in which the link-down is detected during a time period when the link-down is detected by the first failure detection unit or the second failure detection unit; and determining that, by the multiplexing system control unit, when it is determined that the survival information is not received via the LAN other than the LAN in which the link-down is detected during the time period, the processing device of the other system is in a power-off state, and switching the system. ### Claim 8 (depends on 6) The control method according to claim 6, further comprising: transmitting the survival information to the each processing device via the each LAN based on a value obtained by adding an offset indicating a time difference for transmitting the survival information at different timings to the survival time of the own device by the survival monitoring unit.