ePHY MAC Filtering for Wake-on-LAN Power Management

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Solution Overview

Problem

Current Wake-on-LAN (WOL) implementations require main system components to frequently reboot and consume power to detect magic packets, leading to inefficient power management and increased energy usage, as they need to exit sleep mode for every packet transmission to perform MAC address comparisons.

Innovation Solution

Implementing a Media Access Control (MAC) address filtering function on the Ethernet physical layer (ePHY) to compare incoming MAC addresses with stored addresses, allowing the system to remain in standby mode unless a match is detected, thereby reducing unnecessary reboots and power consumption by only waking up when the packet is intended for the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the main system components remain in standby mode to save power, then power consumption is reduced, but the system cannot detect magic packets to wake up

Engineering Contradiction:

Improvepower consumptionVSAvoidWOL functionality

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The system is segmented into two parts: the main system components that can enter standby mode to save power, and the ePHY layer that remains active to detect magic packets. This segmentation allows the system to maintain WOL functionality while reducing overall power consumption during standby.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The ePHY layer acts as an intermediary between the network and the main system components. It monitors incoming traffic and filters magic packets without requiring the main system to wake up, thereby enabling power-saving mode while preserving WOL capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the main system reboots frequently to check for magic packets, then WOL detection is reliable, but system stability decreases and power consumption increases

Engineering Contradiction:

ImproveWOL detectionVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The ePHY layer performs preliminary filtering of incoming packets before they reach the main system. By pre-processing and identifying magic packets at the physical layer, the system avoids unnecessary reboots while maintaining reliable WOL detection.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the main system exits sleep mode for every packet transmission, then packet detection is thorough, but power management efficiency decreases

Engineering Contradiction:

Improvepacket detectionVSAvoidpower management efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Instead of fully waking up the main system for every packet, the ePHY layer performs partial packet detection and filtering. This partial action is sufficient to identify magic packets while allowing the main system to remain in sleep mode, thereby improving power management efficiency.

Inventive Principle:

Principle #16Partial or excessive action

4Measurement precision

If MAC address comparison is performed at the main system level, then address matching is accurate, but system responsiveness during standby is reduced

Engineering Contradiction:

ImproveMAC address matchingVSAvoidwake-up response time

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The patent replaces the mechanical system approach (waking up the main CPU to perform MAC address comparison) with an electronic layer approach (performing MAC address filtering at the ePHY level). This substitution enables accurate MAC address matching while maintaining fast wake-up response time, as the filtering occurs in hardware without requiring full system activation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2673919B1Mac filtering on ethernet PHY for wake-on-lan

Publication Date: 2015.03.11 STANDRD MICROSYSTEMS CORPORATION

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AI summary

To improve Wake on LAN (WOL) functionality of a device, a Media Access Control (MAC) address filtering function (306) may be implemented in the device's Ethernet physical layer (ePHY) block (308). When the ePHY (308) detects a WOL frame, the MAC filtering function (306) in the ePHY (308) may perform address comparison between the MAC address associated with the device (300), and the MAC address contained in the WOL frame. Performing the MAC address comparison within the ePHY (308) allows the main system components, such as the main SOC (302) and other components to remain in standby mode (or sleep mode) until a MAC address match has been determined. Therefore, the main system components do not need to be rebooted every time the device (300) receives a WOL frame, only when there is a match between the MAC address of the system and the MAC address contained in the detected WOL packet.