Selective Reset in Power-Over-Data Linear Bus
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Solution Overview
Problem
In digital video surveillance networks with power-over-data linear bus topology, existing methods cannot perform a selective reset of a device without rebooting all devices connected to the same switch port, leading to unnecessary reboots of functioning devices.
Innovation Solution
A method and apparatus that send a prior-reset notification and physical reset signal along the power-over-data linear bus, allowing processing devices to immunize themselves against reset if they have processed the notification, thereby enabling selective rebooting of faulty devices without affecting others.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a physical reset signal is sent to all devices connected to a switch port in a linear bus topology, then the reset operation can be performed, but all devices including functioning ones will be rebooted unnecessarily
Solution Approach 1:
The patent applies preliminary action by sending a prior-reset notification message to devices before the physical reset signal is transmitted. This notification allows devices to prepare immunization measures in advance, such as storing their operational state or activating protection mechanisms, so that when the reset signal arrives, only the intended faulty device is affected while functioning devices remain protected.
Solution Approach 2:
The patent segments the reset operation into two distinct phases: a notification phase where the prior-reset message is sent to all devices, and an execution phase where the physical reset signal is transmitted. This segmentation allows devices to differentiate between a notification and an actual reset command, enabling selective response where only the faulty device undergoes reset while other devices maintain their operational state.
2Reliability
If power is cut to reset a device in a linear bus topology, then the reset can be performed, but power supply to all devices on the bus is interrupted
Solution Approach 1:
The patent applies local quality by implementing device-specific immunization responses to the reset signal. Each device evaluates the prior-reset notification and its own status to determine whether to respond to the physical reset signal. This allows the reset operation to have a localized effect on only the faulty device while maintaining normal power supply and operation for other devices on the same bus.
Solution Approach 2:
The prior-reset notification message acts as an intermediary between the reset command and the devices. It carries information about the intended reset target and allows devices to mediate their response based on this information. This intermediary mechanism enables the system to distinguish between devices that should be reset and those that should continue operating, preventing unnecessary power interruptions.
3Ease of operation
If a reset signal is transmitted over the power-over-data bus, then reset can be achieved, but functioning devices cannot distinguish it from a power interruption
Solution Approach 1:
The patent uses preliminary action by transmitting the prior-reset notification message before the physical reset signal. This notification provides advance information to devices about the upcoming reset operation, allowing them to preserve their operational state or activate protection mechanisms. This ensures that when the reset signal arrives, devices have already taken necessary precautions to avoid losing their state information.
Solution Approach 2:
The patent implements feedback by having devices acknowledge receipt of the prior-reset notification message. This feedback mechanism allows the initiating device to verify which devices have processed the notification and can be expected to respond appropriately to the subsequent reset signal, ensuring that information is properly communicated and understood across the bus.
Data Source
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AI summary
A method for resetting at least one processing device in a power-over-data linear bus interconnecting a plurality of processing devices, the method comprising, at a first processing device of said plurality of processing devices: - sending a protocol data unit comprising a prior-reset notification to all other processing devices of the plurality of processing devices, and - sending a physical reset signal to all other processing devices of the plurality of processing devices, wherein the prior-reset notification is configured to prevent a processing device that receives the physical reset signal from resetting, if the protocol data unit comprising the prior-reset notification has been previously processed by the processing device.