Inline Power Policing for PoE Budget Management
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Solution Overview
Problem
The IEEE 802.3 standard for Power over Ethernet (PoE) does not effectively manage power allocation to powered devices, leading to situations where devices draw more power than needed, potentially due to incorrect reporting or system variations, resulting in power budget exceedance and device disconnection.
Innovation Solution
A method and apparatus for policing inline power, which monitors power drawn by devices and enforces policing limits, allowing the power sourcing equipment to manage power distribution by prioritizing critical devices and intelligently removing power from non-critical devices when the budget is exceeded, using a 'Power Quality of Service' approach and statistical-based powering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power is allocated based on maximum PD power demand according to IEEE 802.3 standard, then powered devices can receive sufficient power, but power sourcing equipment may allocate more power than needed leading to power budget exhaustion
Solution Approach 1:
The system implements a feedback mechanism by monitoring the actual power drawn by powered devices and comparing it to the allocated power budget. The PSE continuously tracks power consumption and uses this feedback to detect when a PD is drawing more power than reported, triggering policing actions to prevent power budget exhaustion while ensuring reliable operation of critical devices.
Solution Approach 2:
The system changes the parameter of power allocation from static maximum demand-based allocation to dynamic allocation based on actual monitored power draw. By adjusting power limits in real-time based on observed consumption patterns and power budget status, the system optimizes power distribution to match actual needs rather than worst-case scenarios.
2Use of energy by moving object
If power policing limits are enforced strictly, then power budget is maintained, but powered devices may be interrupted or damaged due to abrupt power reduction
Solution Approach 1:
The system takes preliminary action by sending warnings and requests for power reduction before actually enforcing power cuts. The PSE first notifies the PD of the power violation and gives it an opportunity to self-correct by reducing its power draw, only taking punitive action if the PD fails to comply. This gradual approach prevents abrupt interruptions that could damage devices.
Solution Approach 2:
The power policing mechanism is dynamic rather than static, allowing for gradual adjustment of power limits based on device behavior and power budget status. The system can modify policing thresholds and enforcement severity in real-time, adapting to changing conditions while maintaining device operation stability.
3Ease of operation
If power is allocated without monitoring actual draw, then allocation is simple according to IEEE 802.3 classification, but defective PDs or cable losses cause power demand mismatches
Solution Approach 1:
The system replaces the mechanical/classification-based power allocation method with an electronic monitoring and measurement system. Instead of relying solely on IEEE 802.3 classification processes, the PSE uses electronic circuits to continuously measure actual power draw and compare it against allocated budgets, providing precise tracking of power consumption to account for cable losses and defective devices.
Data Source
AI summary
In a wired data telecommunication network power sourcing equipment coupled to a powered device performs policing of power drawn by the powered device. In one embodiment, a method includes monitoring power drawn by the powered devices at power sourcing equipment, each powered device having a policing limit associated therewith. If power drawn by one of the powered devices exceeds the policing limit, it is determined if a power budget of the power sourcing equipment continues to provide power to the powered devices. If the power budget has been exceeded, action is initiated at the power sourcing equipment. The action may include sending or logging a warning, requesting the powered device to reduce its power requirement or removing power from one of the powered devices. An apparatus for policing inline power is also disclosed.