PoE Switch Power Allocation Fairness via Periodic Time Windows

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Solution Overview

Problem

In Power over Ethernet (PoE) systems, computing devices often experience starvation conditions due to oversubscription of power resources, where some devices systematically have their power requests denied as they compete for a fixed amount of power, leading to unfair allocation.

Innovation Solution

Computing devices generate multiple power request and priority options, allowing the switch to allocate power more fairly by considering different power levels and durations, and the switch periodically re-allocates power to ensure all devices receive a minimal amount, preventing starvation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If power allocation is based on request priority, then power can be allocated according to device needs, but starvation conditions occur for certain computing devices

Engineering Contradiction:

Improvepower allocation efficiencyVSAvoidpower delivery guarantee

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements periodic time windows during which starvation-free power allocation is enforced. The switch periodically selects a subset of powered devices and guarantees power delivery to each device in the subset during its designated time window, preventing starvation conditions while maintaining overall system productivity

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent segments the power allocation process into multiple time windows, with each window dedicated to serving a specific subset of powered devices. This segmentation allows the switch to provide guaranteed power delivery to selected devices during their assigned time windows while still responding to priority-based requests from other devices during other time windows

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If multiple power request options are generated, then flexibility in power allocation increases, but device complexity increases

Engineering Contradiction:

Improvepower allocation flexibilityVSAvoidpower management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent enables computing devices to autonomously generate multiple power request options with different power levels and associated time windows. Each device independently determines its own power needs and creates appropriate request options, eliminating the need for complex centralized power management logic and reducing overall system complexity while maintaining high adaptability

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS7908495B2System and method for implementing fairness in the powering of computing devices in a power over ethernet application

Publication Date: 2011.03.15 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

A system and method for implementing fairness in the powering of computing devices in a power over Ethernet (PoE) application. Power supplies in a power sourcing equipment are often oversubscribed. This oversubscription can lead to starvation of certain computing devices that have power requests that are not granted relative to competing requests. A fairness consideration can be implemented to ensure that starvation conditions are avoided.