Method and apparatus for supporting physical layer link-suspend operation between network nodes

• US 6,795,450 B1
• Filed: 09/28/2000
• Issued: 09/21/2004
• Est. Priority Date: 09/28/2000
• Status: Expired due to Term

• Current Assignee: Maxim Integrated Products, Inc. (Analog Devices, Inc.)
• Original Assignee: TDK Semiconductor Corporation (Analog Devices, Inc.)
• Inventors: Mills, Andrew, Andersson, Ralph
• Primary Examiner(s): NGUYEN, BRIAN D
• Application Number:
  US09/676,040
• Time in Patent Office: 1,454 Days
• Field of Search: 370/463, 370/503, 370/509, 370/318, 370/401, 370/465, 370/466, 370/459, 370/458, 370/450, 370/229, 370/311, 370/231, 370/394, 370/419, 370/420, 370/522, 713/300, 713/320, 713/323, 713/324, 713/330, 713/340
• US Class Current: 370/463
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H04L 69/24 Negotiation of communication capabilities
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A link-suspend operation between network nodes in a point-to-point data communications link is presented. Individual network links will have a full power operational mode for supporting full high-bandwidth communication, and a low power “link-suspend” (LS) operational mode for temporary operation when only limited communication is occurring. The communications link is maintained, while cycling transmitter power on and off during idle periods with a duty cycle that substantially reduces physical layer device (PHY) power, using LSPs. LS mode may be negotiated by advertising capabilities between two network devices. Thus, PHYs at either end of a link can notify the other of the capability to support a LS mode of operation and can negotiate parameters for communications using the LS mode. Further, transmitting and receiving continuous idles, valid data frames, and Wake-on LAN (WOL) packets is supported. Similarly, notification of “wake-up” schemes and detection of suspended WOL network device is supported.

Claims

1. An apparatus comprising:

a link suspend device comprising a low power communications mode, said low power communications mode comprising transmission of at least one link suspend pulse;

a plurality of link suspend registers for monitoring and controlling said low power communications mode, said plurality of link suspend registers maintaining characteristics of said link suspend pulse; and

a transmitter comprising a plurality of circuit elements coupled to said link suspend device, said transmitter configured to transmit said link suspend pulses and to power down at least one of said plurality of circuit elements between said transmissions of said link suspend pulses.

2. The apparatus of claim 1, further comprising a generator coupled to said transmitter, said generator configured to provide timing pulses to said transmitter.

3. The apparatus of claim 1, further comprising a transmit functions controller coupled to said transmitter, said transmit functions controller configured to provide control of said transmitter.

4. The apparatus of claim 1, further comprising a receiver coupled to said link suspend device.

5. The apparatus of claim 4, wherein said receiver is configured to detect valid ones of said link suspend pulses.

6. The apparatus of claim 5, wherein said receiver is configured to detect the absence of said link suspend pulses.

7. The apparatus of claim 4, wherein said receiver is configured to detect a valid data frame template while in said low power communications mode.

8. The apparatus of claim 7, wherein said link suspend device is configured to continue said low power communications mode upon receipt of a valid data frame template and process data contained in said valid data frame template.

9. The apparatus of claim 7, wherein upon receipt of a valid data frame template said link suspend device is configured to:

bring a host device coupled to said link suspend device out of a sleep state;

process data contained in said valid data frame template; and

continue said low power communications mode.

10. The apparatus of claim 4, further comprising a detector coupled to said receiver, said detector configured to detect normal and fast link pulses.

11. The apparatus of claim 10, wherein said detector is configured to detect valid data frame templates.

12. The apparatus of claim 10, further comprising a receive functions controller coupled to said receiver, said receive functions controller configured to provide control of said receiver.

13. The apparatus of claim 4, further comprising a negotiation device coupled to said transmitter, said negotiation device configured to negotiate a communications link.

14. The apparatus of claim 13, wherein said negotiation device is further configured to provide at least one first link parameter to at least one link partner, and receive at least one second link parameter from said at least one link partner.

15. The apparatus of claim 14, wherein said first and said second link parameters comprise information for initiating and controlling said low power communications mode.

16. The apparatus of claim 14, wherein said parameters comprise a wake-up code for identifying a data packet that upon receipt will bringing a host device attached to said link suspend device out of a sleep state.

17. The apparatus of claim 16, wherein said wake-up codes are transmitted and received, using Next Page messages.

18. The apparatus of claim 14, further comprising:

a mode control parameter for transmitting to said link partner, said mode control parameter configured to cause said partner to suspend transmission of link suspend pulses and continue to receive link suspend pulses.

19. The apparatus of claim 13, wherein said negotiation device comprises an auto negotiation device.

20. The apparatus of claim 1, wherein said transmitter is further configured to power down at least one of said plurality of circuit elements between transmissions of valid data templates.

21. The apparatus of claim 1, further comprising an interface coupled to said link suspend device, said interface configured to interface with a media controller.

22. The apparatus of claim 21, wherein said interface further comprises at least one register and interface logic for initiating and controlling said low power communications mode.

23. The apparatus of claim 22, further comprising:

a register for providing a link partner with a wake-up code, said wake-up code configured to notify a host device attached to said link suspend device of a wake up mode employed by said link suspend device; and

a register for receiving and recording a partner wake-up code, said partner wake-up code configured to notify a host device attached to a link partner of said wake up mode employed by said link suspend device.

24. The apparatus of claim 21, wherein said interface is configured to receive a first set of data from said media controller for transmitting onto a link, and is configured to provide a second set of data received from said link to said media controller.

25. The apparatus of claim 21, wherein said plurality of link suspend registers comprises an identification register, said identification register configured to provide to a link partner, information used to define operational parameters for link partner operation related to said suspend pulses.

26. The apparatus of claim 25, wherein said plurality of link suspend registers comprises a control register, said control register configured to provide to a link partner, information used to initiate and control said low power communications mode.

27. The apparatus of claim 26, wherein said plurality of link suspend registers comprises a status register, said status register configured to receive and retain from a link partner, information used to initiate and control said low power communications mode.

28. An apparatus comprising:

a link suspend device comprising a low power communications mode, said low power communications mode comprising transmission of at least one link suspend pulse;

a transmitter comprising a plurality of circuit elements coupled to said link suspend device, said transmitter configured to transmit said link suspend pulses and to power down at least one of said plurality of circuit elements between said transmissions of said link suspend pulses;

a receiver coupled to said link suspend device, said receiver configured to detect said link suspend pulses and data frame templates while in said low power communications mode;

a detector coupled to said receiver, said detector configured to detect normal link pulses, fast link pulses, and valid data frame templates;

a plurality of link suspend registers for monitoring and controlling said low power communications mode;

a negotiation device coupled to said link suspend device, said negotiation device configured to negotiate a communications link; and

an interface coupled to said link suspend device, said interface configured to interface with a media controller.

29. The apparatus of claim 28, wherein said apparatus comprises a computer network physical layer device.

30. The apparatus of claim 28, wherein said transmitter is further configured to power down at least one of said plurality of circuit elements between transmissions of valid data templates.

31. The apparatus of claim 28, wherein said plurality of link suspend registers comprises:

an identification register coupled to said link suspend device, said identification register configured to provide to a link partner, a first set of information used to define operational parameters for link partner operation related to said link suspend pulses;

a control register coupled to said link suspend device, said control register configured to provide a second set of information used to initiate and control said low power communications mode with a link partner; and

a status register coupled to said link suspend device, said status register configured to receive and retain a third set of information used to initiate and control said low power communications mode with a link partner.

32. A method for providing a low power communications mode, comprising:

negotiating a link with a link partner, wherein said negotiating comprises;

transmitting to said link partner parameters identifying available communications modes;

receiving from said link partner parameters identifying available link partner communications modes;

receiving from said partner parameters identifying a low power communications mode as one of said available link partner communications modes;

entering said low power communications mode;

transmitting at least one link suspend pulse;

powering down at least one of a plurality of transmitter circuit elements between transmission of said link suspend pulses;

receiving a signal from said link partner;

detecting a receive link suspend pulse in said signal;

detecting a receive data frame template in said signal;

supporting said link during detection of said receive data frame template;

interpreting receive data contained in said receive data frame templates;

providing said receive data to a media controller;

obtaining transmit data from said media controller;

transmitting said transmit data in a transmit data frame template onto said link.

33. A method for providing a low power communications mode, comprising:

negotiating a link with a link partner;

receiving a first set of parameters identifying a low power communications mode as one of available communications modes of said link partner, and storing said first set of parameters in a first link suspend register;

transmitting a second set of parameters from a second link suspend register identifying said low power communications mode as one of available communications modes;

entering said low power communications mode;

transmitting at least one link suspend pulse during said low power communications mode;

powering down at least one of a plurality of transmitter circuit elements between transmission of said link suspend pulses.

34. The method of claim 33, wherein said negotiating comprises:

transmitting to said link partner said second set of parameters identifying available communications modes;

receiving from said link partner said first set of parameters identifying available link partner communications modes.

35. The method of claim 34, wherein said negotiating comprises transmitting to said partner parameters identifying available communications modes, wherein said negotiating further comprises receiving from said link partner parameters identifying available link partner communications modes.

36. The method of claim 34, further comprising the steps of:

detecting a receive link suspend pulse in a signal from said link partner;

detecting a receive data frame template in said signal;

bringing a host device coupled to a link suspend device out of a sleep state upon receipt of a valid data frame template;

processing data contained in said valid data frame template; and

continuing said low power communications mode.

37. The method of claim 36, further comprising reentering said negotiating upon loss of said low power communications mode.

38. The method of claim 34, wherein said negotiating further comprises:

retaining parameters for said negotiating of said link;

transmitting to said link partner parameters identifying said low power communications mode as one of said available communications modes;

receiving from said link partner link partner parameters identifying said low power communications mode as one of said available communications modes of said link partner;

transmitting to said link partner information identifying transmit link suspend pulses to be transmitted to said link partner; and

receiving from said link partner information identifying receive link suspend pulses to be received from said link partner.

39. The method of claim 33, further comprising steps of:

receiving a signal from said link partner;

detecting a receive link suspend pulse in said signal;

detecting a receive data frame template in said signal;

detecting absence of said link suspend pulses transmitted by said link partner;

supporting said link during detection of said receive data frame template;

providing receive data in said receive data frame template to a media controller;

obtaining transmit data from said media controller; and

transmitting said transmit data in a transmit data frame template onto said link.

40. The method of claim 33, further comprising:

transmitting at least one valid data template while in said low power communications mode; and

powering down at least one of said plurality of transmitter circuit elements between transmission of said valid data templates.

41. The method of claim 40, further comprising the steps of:

continuing, said low power communications mode;

discontinuing said transmission of said link suspend pulses; and

transmitting data frame templates.

42. The method of claim 33, further comprising the steps of:

controlling said low power communications mode with a link suspend controller;

discontinuing said low power communications mode upon receipt of a data frame template containing data requesting said low power communications mode to be discontinued.

43. The method claim 33, further comprising the steps of:

continuing said low power communications mode upon receipt of a valid data frame template; and

processing data contained in said valid data frame template.

44. The method of claim 33, further comprising:

detecting received link suspend pulses in a signal;

discontinuing said low power communications mode upon discontinuation of said detection of said link suspend pulses.

45. The method of claim 33, further comprising:

detecting receive data frame template in a signal;

detecting timing pulses of said receive data frame template with a pulse detector; and

interpreting receive data contained in said receive data frame templates.

46. The method of claim 45, further comprising:

discontinuing said low power communications upon discontinuation of said detection of said receive data frame template.

47. The method of claim 33, further comprising:

transmitting a mode control parameter to said link partner, said mode control parameter configured to cause said link partner to discontinue transmitting link suspend pulses while said link partner continues receiving link suspend pulses.