Patent ID: 8448007

Claim:
A physical interface transceiver (PHY) for use as a local PHY in a network device, comprising: a transmit buffer for storing data received from a local media access controller (MAC) co-located with the local PHY, the data to be transmitted on a communications link to far-end PHY of a remote communications device; and timing and control circuitry configured to: monitor for transmission of data by the local MAC when the far-end PHY is in a low-power operating state in which it cannot receive a data transmission from the local MAC; upon detecting transmission of data by the local MAC, buffering an initial amount of the data in the transmit buffer and sending a notification to the far-end PHY causing the far-end PHY to transition to a higher-power operating state over a wake-up interval; and selectively sending a data delay indicator to the local MAC based on a relationship between the wake-up interval and a time-measured size of the transmit buffer, the data delay indicator causing the local MAC to cease transmission of data and being sent when the relationship between the wake-up interval and the time-measured size of the transmit buffer would result in overrunning the transmit buffer if transmission by the local MAC were permitted to continue throughout the wake-up interval.