SYSTEM AND METHOD FOR DYNAMICALLY SWAPPING MASTER AND SLAVE PHYS TO ALLOW ASYMMETRY IN ENERGY EFFICIENT ETHERNET

• US 20090225779A1
• Filed: 03/02/2009
• Published: 09/10/2009
• Est. Priority Date: 03/04/2008
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Powell, Scott, Diab, Wael William
• Granted Patent: US 8,009,695 B2
• Time in Patent Office: Days
• US Class Current: 370/469
• CPC Class Codes: H04J 3/0641 Change of the master or reference, e.g. take-over or failure of the master
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H04L 7/033 using the transitions of the received signal to control the phase of the synchronising-signal-generating means, e.g. using a phase-locked loop
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A system and method for dynamically swapping master and slave physical layer devices (PHYs) in energy efficient Ethernet (EEE). A physical layer communication mechanism can be used to dynamically reassign the master/slave assignments to facilitate the asymmetric application of EEE to a link.

Claims

1. An energy efficient Ethernet method in a first physical layer device operating in a master mode that communicates with a second physical layer device operating in a slave mode, comprising:

after a determination that a direction of transmission between a transmitter in the first physical layer device and a receiver in the second physical layer device should enter an outage interval, transmitting a control message from the first physical layer device to the second physical layer device;

switching the first physical layer device from a master mode to a slave mode, wherein said slave mode is responsive to the second physical layer device that has switched from a slave mode to a master mode in response to said transmitted control message; and

transitioning the transmitter in the first physical layer device into an outage interval.

2. The method of claim 1, further comprising transmitting an in-band control message.

3. The method of claim 1, further comprising transmitting an out-of-band control message.

4. The method of claim 1, wherein said switching comprises activating a phase locked loop for use by the receiver in the first physical layer device.

5. The method of claim 1, wherein said transitioning comprises entering a subset physical layer device mode.

6. The method of claim 1, wherein said transitioning comprises entering a low power idle mode.

7. An energy efficient Ethernet method in a first physical layer device operating in a slave mode that communicates with a second physical layer device operating in a master mode, comprising:

receiving a control message by the first physical layer device from the second physical layer device;

switching the first physical layer device from a slave mode to a master mode; and

transitioning the receiver in the first physical layer device into an outage interval.

8. The method of claim 7, further comprising receiving an in-band control message.

9. The method of claim 7, further comprising receiving an out-of-band control message.

10. The method of claim 7, wherein said switching comprises activating a free running oscillator for use by the transmitter in the first physical layer device.

11. The method of claim 7, wherein said transitioning comprises entering a subset physical layer device mode.

12. The method of claim 7, wherein said transitioning comprises entering a low power idle mode.

13. The method of claim 7, wherein said master mode and slave mode is for a loop timing function.

14. An energy efficient Ethernet method, comprising:

operating a first physical layer device as a master physical layer device;

determining that a rate of only one direction of a link between said first physical layer device and a second physical layer device is to be reduced; and

transmitting a control message from said first physical layer device to said second physical layer device that is operating as a slave physical layer device, said control message requesting a reassignment of said second physical layer device as a master physical layer device.

15. The method of claim 14, wherein said transmitting comprises transmitting using physical layer communication.

16. The method of claim 15, wherein said transmitting comprises transmitting using sequence ordered sets.