SYSTEM AND METHOD FOR SQUELCHING A RECOVERED CLOCK IN AN ETHERNET NETWORK

1 . A method for squelching a clock signal in an Ethernet physical layer (PHY) circuit of an Ethernet switch, the Ethernet switch configured to route data from a first port to a second port and including a switch coupled to each of the ports by at least the PHY circuit and a media access controller (MAC) circuit, the first port and the second port each configured for coupling to a transmission medium connected to computer systems, the PHY circuit configured to receive data from and transmit data to a communication medium, and the clock signal being a clock signal provided to the MAC circuit, the method comprising:

receiving information via the communication medium;

recovering a clock signal based on the information; and

squelching the recovered clock signal based on a descrambler status, a remote receiver status and a link status.

2 . The method of claim 1 , wherein the recovered clock is squelched when at least one of the descrambler status signal, the remote receiver status signal and the link status signal indicates a link failure.

3 . The method of claim 1 , wherein the communication medium is a fiber medium.

4 . The method of claim 1 , wherein the communication medium is a copper medium.

5 . The method of claim 1 , wherein the recovered clock signal is further squelched based on a mode of the link.

6 . The method of claim 5 , wherein the recovered clock signal is squelched when the link is in a 10 Base-T mode.

7 . The method of claim 5 , wherein the recovered clock signal is squelched when the link is in a 1000 Base-T master mode.

8 . The method of claim 1 , wherein the recovered clock signal is output when none of the at least one signal indicative of the status of the link is indicative of a link failure and an active link is in a mode other than 10 Base-T mode and 1000 Base-T master mode.

9 . A system at a local node for inhibiting a recovered clock signal clock in an Ethernet network including the local node coupled to a remote node by a link, the system comprising:

a receiver for recovering at least one clock signal from data received from the remote node for provision to a media access controller (MAC) of the local node;

link monitor circuitry coupled to the receiver for monitoring a status of the link, and for generating a link status signal; and

clock squelch circuitry to inhibit the at least one recovered clock signal from being output to the MAC as a clock signal based on a descrambler status, a remote receiver status and the link status signal.

10 . The system of claim 9 , wherein the receiver recovers a plurality of clock signals from data received from the remote node.

11 . A method for squelching a clock signal in a physical layer (PHY) circuit of an Ethernet switch, the clock signal being a clock signal provided to a media access controller (MAC) circuit of the Ethernet switch, the method comprising:

recovering a clock signal from the local node to the remote node;

determining a mode for the link; and

squelching the recovered clock signal based on a comparison of the determined mode of the link with a predetermined mode for suppression.

12 . The method of claim 11 , wherein the recovered clock signal is squelched when

12 . The method of claim 11 , wherein the recovered clock signal is squelched when the determined mode corresponds to the predetermined mode for suppression.

13 . The method of claim 12 , wherein the predetermined mode for suppression is a 10 Base-T mode.

14 . The method of claim 12 , wherein the predetermined mode for suppression is a 1000 Base-T master mode.