Energy Efficient Ethernet Quiet/Refresh Cycling for Glitch Filtering
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Solution Overview
Problem
The IEEE 802.3ch™ Standard's Energy Efficient Ethernet (EEE) mechanism for low power idle (LPI) mode can lead to unpredictable behavior and increased power consumption due to glitches and transitory signals after a sleep signal, as the receiver misinterprets these signals as alert signals, prompting unnecessary power-ups.
Innovation Solution
Implementing a quiet/refresh cycle with alternating quiet and alert time windows, where the receiver immediately transitions to ignoring signals after a sleep signal, ensuring it does not misinterpret glitches or transitory signals, and only powers up during designated refresh windows for synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the receiver keeps receive circuitry powered up continuously to be prepared for alert signals, then the receiver can respond quickly to wake signals, but power consumption increases significantly
Solution Approach 1:
The receiver powers up receive circuitry periodically during alert time windows instead of continuously. The quiet/refresh cycle creates periodic intervals where the receiver is awake to detect alert signals, then sleeps during quiet time periods. This periodic operation maintains the ability to respond to wake signals while dramatically reducing average power consumption compared to continuous operation.
2Speed
If the receiver powers up immediately after receiving a sleep signal to detect alert signals, then the receiver can detect wake signals promptly, but the receiver may misinterpret glitches and transitory signals as alert signals causing unpredictable behavior
Solution Approach 1:
The receiver performs preliminary action by transitioning to a quiet time window state immediately after receiving the sleep signal, where it deliberately ignores incoming signals. This preliminary ignoring period allows the receiver to wait for the formal alert time window before becoming attentive, preventing misinterpretation of transient glitches as valid alert signals while maintaining readiness to detect legitimate wake signals when the alert time window begins.
3Reliability
If the receiver transitions to quiet time window immediately after sleep signal, then the receiver ignores glitches and transitory signals, but the receiver must wait until alert time window to detect wake signals
Solution Approach 1:
The detection period is segmented into distinct temporal phases: quiet time window (ignoring period), alert time window (detection period), and wake signal transmission period. This segmentation separates the function of filtering false signals from the function of detecting valid signals, ensuring reliable operation while maintaining timely response through the structured timing of these segments.
Data Source
AI summary
A network interface device operates in a normal transmit operating mode in which the network interface device continually receives transmission symbols from a link partner via the communication link. The network interface device determines that receive circuitry of the network interface device is to transition to a low power mode in response to receiving a sleep signal from the link partner. The network interface device then operates according to a quiet/refresh cycle of the low power mode to conserve power. The quiet/refresh cycle corresponds to a time schedule that includes a refresh time window in which receive circuitry of the network interface device is to be powered to receive a refresh signal from the link partner. Immediately after transmission of the sleep signal, the network interface device transitions to a quiet time window of the time schedule in which the network interface device ignores transmissions from the link partner.