Method and apparatus for transparent implementation of link-suspend capabilities in network devices

摘要

A method and apparatus for transparent implementation of link-suspend capabilities in network devices is presented. Accordingly, a new generation of network devices capable of operating in both the full power operational mode of prior art network devices, and a low power "link-suspend" operational mode are presented. The low power "link-suspend" (LS) mode reduces the power consumption of a LAN communications link at the physical layer by eliminating the need to transmit continuous standard idles to maintain link between two linked partners. In the LS mode, a low duty cycle "link-suspend-packet" (LSP) is transmitted between periods of silent line state (SLS). During the SLS, which is a non-data transmission period, the transmitter may be turned off to conserve power. The transmitter power is turned back on when it is time to transmit LSPs or data. A link suspend capable PHY may be connected to an existing network of PHY devices without any change to the existing network devices. Data communicated to an LS capable PHY operating in either the LS mode or the standard protocol mode is not lost so long as the link is maintained. Thus, incorporating an LS capable PHY into an existing network of LS capable and/or prior art PHYs is transparent because operation in LS mode is negotiated between the link partners. LS capable PHYs advertise their capabilities during link negotiation and parameters passed are used to determine the proper mode of operation.