LLDP-MED PSE Identification to Prevent False Powered Device Detection
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Solution Overview
Problem
Existing Power over Ethernet (PoE) systems face disruptions due to false detection of Power Sourcing Equipment (PSE) as a Legacy Powered Device, leading to unintended power injection and network interruptions, which can cause reliability issues and power dissipation problems.
Innovation Solution
Implementing the use of Link Layer Discovery Protocol (LLDP) and Media Endpoint Discovery (MED) to enable PSE devices to identify each other and disable automatic PD detection, preventing power injection between PSE devices by exchanging custom Type, Length, and Value (TLV) messages to correctly identify and manage power sourcing equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If automatic PD detection is enabled in PoE systems, then legacy powered devices can be detected and powered, but false detection of PSE as legacy PD occurs leading to unintended power injection
Solution Approach 1:
The patent introduces LLDP-MED protocol as an intermediary communication mechanism between PSE devices. This protocol exchange allows PSE devices to identify each other's true nature before power injection occurs, preventing false detection while maintaining compatibility with legacy PDs. The LLDP-MED frames act as a mediator that carries identification information to resolve the detection ambiguity.
Solution Approach 2:
The patent implements preliminary identification through LLDP-MED frame exchange before the power injection decision is made. By performing this identification action in advance, the system prevents the harmful false detection from occurring, rather than attempting to correct it after power has been injected.
2Reliability
If PSE devices exchange identification information to prevent false detection, then reliability improves, but network protocol complexity increases
Solution Approach 1:
The patent leverages the existing LLDP-MED protocol framework, which is already widely implemented in network devices for discovery and management functions. By extending this existing universal protocol to include PSE identification capabilities, the solution avoids creating a new proprietary protocol, thereby minimizing added complexity while achieving reliable PSE detection prevention.
3Loss of energy
If power injection is prevented between PSE devices, then power dissipation is reduced, but detection and identification difficulty increases
Solution Approach 1:
The patent uses LLDP-MED protocol frames to convey identification information that effectively 'colors' or tags PSE devices differently from regular PDs. This information exchange makes PSE devices easily identifiable through protocol messages, transforming the detection difficulty into a simple protocol-based identification process.
Data Source
AI summary
Described herein are systems, devices, techniques and products for minimizing disruption to network systems due to false detection of a Power over Ethernet (PoE) Power Sourcing Equipment (PSE) as a Powered Device (PD). The disclosed systems, devices, techniques and products provide a way for a PSE to identify itself and avoid being detected as a legacy PD. The disclosed systems, devices, techniques and products further provide a way for a PSE to identify devices that do not require power from the PSE, such as another PSE or a device that is not a PD, and disable automatic PD detection, disable PoE, or otherwise prevent injection of power/current to the other device.