Energy efficient data transmission

Abstract

A method and apparatus for data transmission at energy efficient rates. An embodiment of an apparatus includes a port for the transfer of data. The port has an active state in which the port may transmit or receive data and an inactive state in which the port does not transmit or receive data. The apparatus further includes logic to control the transfer of data. The logic places the port into the active state for a first time period for the transfer of data and places the port into the inactive state for a second time period. The logic further prevents transfer of data during the inactive state.

1 - 28 . (canceled) 
   
   
       29 . A method comprising:
 at a first Ethernet link partner coupled by an Ethernet link to a second Ethernet link partner:
 causing a PHY of the first Ethernet link partner to enter a lower power state from an active state, wherein the lower power state consumes less power than the active state but maintains the Ethernet link between the first Ethernet link partner and the second Ethernet link partner; 
 enqueuing data packets for transmission to the second Ethernet link partner via the link while in the lower power state; and 
 transmitting the enqueued data packets after exiting the lower power state. 
   
   
   
       30 . The method of  claim 29 ,
 further comprising, at the first Ethernet link partner, causing a media access controller (MAC) of the first Ethernet link partner to enter a lower power state from an active state.   
   
   
       31 . The method of  claim 29 ,
 further comprising receiving a message from the second Ethernet link partner to prevent the first Ethernet link partner from transmitting data packets; and   wherein the causing the PHY to enter a lower power state and the enqueuing occur in response to the message.   
   
   
       32 . The method of  claim 29 , further comprising:
 at the second Ethernet link partner:
 preventing the first Ethernet link partner from transmitting data packets for a certain amount of time; and 
 in response to the preventing, entering a lower power state. 
   
   
   
       33 . The method of  claim 29 , further comprising at the first Ethernet link partner determining an Ethernet transmission link speed based on the amount of data to transmit and the energy consumed by operating at different transmission speeds. 
   
   
       34 . The method of  claim 33 , wherein the determining the Ethernet transmission link speed further comprises determining based on an amount of energy consumed during an idle transmission period. 
   
   
       35 . The method of  claim 29 , wherein the maintaining the Ethernet link comprises reducing the amount of time to reenter an active state compared to the amount of time to reenter an active state if the Ethernet link were not maintained. 
   
   
       36 . An apparatus, comprising:
 a media access controller;   a PHY; and   logic to
 cause the PHY to enter a lower power state from an active state, wherein the lower power state consumes less power than the active state but maintains the Ethernet link to an Ethernet link partner; 
 enqueue data packets for transmission to the Ethernet link partner via the link while in the lower power state; and 
 transmit the enqueued data packets after exiting the lower power state. 
   
   
   
       37 . The apparatus of  claim 36 ,
 wherein the logic further comprises logic to cause the media access controller to enter a lower power state from an active state.   
   
   
       38 . The apparatus of  claim 36 ,
 further comprising logic to receive a message from the Ethernet link partner to prevent the apparatus from transmitting data packets; and   wherein the causing the PHY to enter a lower power state and the enqueuing occur in response to the message.   
   
   
       39 . The apparatus of  claim 36 , further comprising logic to:
 preventing an Ethernet link partner from transmitting data packets for a certain amount of time; and   in response to the preventing, entering a lower power state.   
   
   
       40 . The apparatus of  claim 36 , further comprising logic to determine an Ethernet transmission link speed based on the amount of data to transmit and the energy consumed by operating at different transmission speeds. 
   
   
       41 . The apparatus of  claim 40 , wherein the logic to determine the Ethernet transmission link speed further comprises determining based on an amount of energy consumed during an idle transmission period. 
   
   
       42 . The apparatus of  claim 40 , wherein the logic to maintain the Ethernet link comprises logic to reduce the amount of time to reenter an active state compared to the amount of time to reenter an active state if the Ethernet link were not maintained.