Network interface system and method for dynamically switching between different physical layer devices

• US 6,516,352 B1
• Filed: 08/17/1998
• Issued: 02/04/2003
• Est. Priority Date: 08/17/1998
• Status: Expired due to Term

• Current Assignee: Jato Technologies, Inc. (Intel Corporation)
• Original Assignee: Intel Corporation
• Inventors: Booth, Bradley J., Sharp, Robert O., Kass, William, Fesas, Nestor A. Jr.
• Primary Examiner(s): Etienne, Ario
• Assistant Examiner(s): EDELMAN, BRADLEY E
• Application Number:
  US09/135,074
• Time in Patent Office: 1,632 Days
• Field of Search: 709/250, 709/228, 370/463, 340/2, 340/8, 340/2.2, 340/825, 710/131, 710/38
• US Class Current: 709/250
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling

Abstract

A system and method for dynamically switching between different physical layer devices (PHYs) in a network interface. The system comprises a network interface in a network device, e.g., a network card in a computer system which includes a first PHY device and a second PHY device. The first PHY device is coupled to a first transmission medium (such as fiber-optic cable) which requires a continuous connection to the computer system when active. For a SERDES device, this continuous connection is required because the PHY needs constant access to its physical coding sublayer (PCS), which is located external to the PHY. The second PHY device is coupled to a second transmission medium (such as copper cable) which does not require this continuous connection. This second PHY may be, for example, a G/MII device, which includes the PCS internally. The network interface card further includes a link switching unit, a physical layer interface unit, and a control unit. The control unit generates a select signal indicating which physical layer device is currently selected. Accordingly, the link switching unit transfers data between the physical layer interface unit and the currently selected physical layer device. The physical layer interface unit receives incoming data from either the link switching unit or an external interface of the network interface card. The physical layer interface unit includes two sub-layers corresponding to each of the physical devices. These sub-layers each produce outgoing data in response to the incoming data, and the appropriate outgoing data is chosen based on the currently selected physical layer device.

Claims

1. A network interface card configured for use within a network device comprising:

a first physical layer device configured to be coupled to a first transmission medium, wherein said first transmission medium is continuously linked to said network device whenever said first physical layer device is active, and wherein said first transmission medium is a fiber-optic transmission medium;

a second physical layer device configured to be coupled to a second transmission medium, wherein said second transmission medium is a non-fiber-optic transmission medium;

a link switching unit coupled to said first physical layer device and said second physical layer device and configured to dynamically switch between said first physical layer device and said second physical layer device in establishing a network link; and

a physical layer interface unit coupled to said link switching unit, the physical layer interface unit comprising a first physical layer interface sub-unit and a second physical layer interface sub-unit, wherein the first physical layer interface sub-unit is configured to process incoming data according to an interface of the first physical layer device and the second physical layer interface sub-unit is configured to process incoming data according to an interface of the second physical layer device.

2. The network interface card of claim 1, wherein said second physical layer device is a MII or GMII device.

3. The network interface card of claim 1, wherein said link switching unit is further configured to establish said network link by coupling to only one of said first physical layer device or said second physical layer device at a time.

11. The network interface card of claim 3, further comprising a control unit configured to generate a select signal indicative of whether said first physical layer device or said second physical layer device is currently selected, wherein said control unit is configured to convey said select signal to said link switching unit and said physical layer interface unit.

12. The network interface card of claim 11, wherein said link switching unit is configured to transfer data between said physical layer interface unit and a currently selected physical layer device indicated by said select signal.

13. The network interface card of claim 12, wherein said physical layer interface unit is coupled to an external interface of said network interface card which couples said network interface card to a remainder of said computer system.

14. The network interface card of claim 13, wherein said physical layer interface unit is configured to transfer data between said link switching unit and said external interface.

15. The network interface card of claim 14, wherein said physical layer interface unit is configured to process incoming data from both said external interface and said link switching unit, and wherein said physical layer interface unit is configured to process said incoming data according to said currently selected physical layer device indicated by said select signal in order to generate outgoing data.

16. The network interface card of claim 15, wherein said physical layer interface unit includes:

a first physical layer interface sub-unit which processes said incoming data according to a first interface specified by said first physical layer device;

a second physical layer interface sub-unit which processes said incoming data according to a second interface specified by said second physical layer device.

17. The network interface card of claim 16, wherein said outgoing data is selected from said first physical layer interface sub-unit in response to said first physical layer device being currently selected, and wherein said outgoing data is selected from said second physical layer interface sub-unit in response to said second physical layer device being currently selected.

18. The network interface card of claim 13, wherein said first physical layer interface sub-unit is a physical coding sublayer (PCS).

19. The network interface card of claim 13, wherein said second physical layer interface sub-unit is a MII or GMII Reconciliation sublayer.

4. A network interface card configured to be used within a computer system, comprising:

a first physical layer device configured to be coupled to a first transmission medium, wherein said first transmission medium is a fiber-optic transmission medium;

a second physical layer device configured to be coupled to a second transmission medium, wherein said second transmission medium is a non-fiber-optic transmission medium;

a link switching unit coupled to said first physical layer device and said second physical layer device and configured to dynamically switch between said first physical layer device and said second physical layer device in establishing a network link; and

a physical layer interface unit coupled to said link switching unit, the physical layer interface unit comprising a first physical layer interface sub-unit and a second physical layer interface sub-unit, wherein the first physical layer interface sub-unit is configured to process incoming data according to an interface of the first physical layer device and the second physical layer interface sub-unit is configured to process incoming data according to an interface of the second physical layer device.

5. The network interface card of claim 4, wherein said link switching unit is configured to switch from said first physical layer device to said second physical layer device in response to detecting that a link established via said first physical layer device is down or unreliable.

6. The network interface card of claim 4, wherein said link switching unit is configured to switch from said second physical layer device to said first physical layer device in response to detecting that a link established via said second physical layer device is down or unreliable.

7. The network interface card of claim 4, wherein said first physical layer device is a SERDES device.

8. The network interface card of claim 7, wherein said second physical layer device is a MII or GMII device.

9. The network interface card of claim 4, wherein said second physical layer device is a GMII device.

10. The network interface card of claim 4, wherein said second physical layer device is a MII device.

20. A computer system, comprising:

a network interface card, the network interface card comprising a physical layer interface unit, the physical layer interface unit comprising a fist physical layer interface sub-unit and a second physical layer interface sub-unit, wherein the first physical layer interface sub-unit is configured to process incoming data according to an interface of a first physical layer device and the second physical layer interface sub-unit is configured to process incoming data according to an interface of a second physical layer device, the network interface card configured to establish a network link via a first transmission medium or a second transmission medium, wherein said first transmission medium is a fiber-optic medium; and

wherein said second transmission medium is a non-fiber-optic medium;

wherein said network interface card is configured to dynamically switch between said first transmission medium and said second transmission medium in establishing said network link.

21. The computer system of claim 20, wherein said network interface card is configured to switch from said first transmission medium to said second transmission medium in response to detecting that a link established via said first transmission medium is down.

22. The computer system of claim 20, wherein said network interface card is configured to switch from said second physical layer device to said first physical layer device in response to detecting that a link established via said second physical layer device is down.

23. The computer system of claim 20, wherein said first physical layer device is a SERDES device.

24. The computer system of claim 23, wherein said second physical layer device is a MII or GMII device.

25. The computer system of claim 20, wherein said second physical layer device is a GMII device.

26. The computer system of claim 20, wherein said second physical layer device is a MII device.

27. The computer system of claim 20, further comprising a link switching unit coupled to said first physical layer device and said second physical layer device.

28. The computer system of claim 27, further comprising a physical layer interface unit coupled to said link switching unit.

29. The computer system of claim 28, further comprising a control unit configured to generate a select signal indicative of whether said first physical layer device or said second physical layer device is currently selected, wherein said control unit is configured to convey said select signal to said link switching unit and said physical layer interface unit.

30. The computer system of claim 29, wherein said link switching unit is configured to transfer data between said physical layer interface unit and a currently selected physical layer device indicated by said select signal.

31. The computer system of claim 30, wherein said physical layer interface unit is coupled to an external interface of said network interface card which couples said network interface card to a remainder of said computer system.

32. The computer system of claim 29, wherein said physical layer interface unit is configured to transfer data between said link switching unit and said external interface.

33. The computer system of claim 32, wherein said physical layer interface unit is configured to process incoming data from both said external interface and said link switching unit, and wherein said physical layer interface unit is configured to process said incoming data according to said currently selected physical layer device indicated by said select signal in order to generate outgoing data.

34. The computer system of claim 33, wherein said physical layer interface unit includes:

a first physical layer interface sub-unit which processes said incoming data according to a first interface specified by said first physical layer device;

a second physical layer interface sub-unit which processes said incoming data according to a second interface specified by said second physical layer device.

35. The computer system of claim 34, wherein said outgoing data is selected from said first physical layer interface sub-unit in response to said first physical layer device being currently selected, and wherein said outgoing data is selected from said second physical layer interface sub-unit in response to said second physical layer device being currently selected.

36. The computer system of claim 31, wherein said first physical layer interface sub-unit is a physical coding sublayer (PCS).

37. The computer system of claim 31, wherein said second physical layer interface sub-unit is a MII or GMII Reconciliation sublayer.

38. A method for establishing a link to a network in a computer system, said method comprising:

dynamically switching between coupling to a first physical layer interface device and coupling to a second physical layer interface device in order to establish said link to said network;

wherein said first physical layer interface interfaces to a fiber-optic transmission medium, and wherein said second physical layer interface device interfaces to a non-fiber- optic transmission medium; and

dynamically switching between processing data in a first physical layer interface sub-unit that is configured to process data according to an interface of the first physical layer interface device and processing data in a second physical layer interface sub-unit that is configured to process data according to an interface of the second physical layer interface device.

39. The method of claim 38, wherein said first physical layer device is a SERDES device.

40. The method of claim 39, wherein said second physical layer device is a MII or GMII device.

41. The method of claim 38, wherein said second physical layer device is a GMII device.

42. The method of claim 38, wherein said second physical layer device is a MII device.

43. The method of claim 38, further comprising:

determining that a first network link established via said first physical layer device is down or unreliable;

performing said dynamic switching from said first physical layer device to said second physical layer device in response to said determining.

44. The method of claim 43, wherein said performing said dynamic switching from said first physical layer device to said second physical layer device includes:

indicating that said first network link is going off-line;

isolating said first physical layer device;

signaling a link switching unit to begin conveying data to and from said second physical layer device instead of said first physical layer device;

signaling a physical layer interface unit that data transmitted to or received from said link switching unit corresponds to said second physical layer device instead of said first physical layer device;

configuring said second physical layer device;

de-isolating said second physical layer device.

45. The method of claim 38, further comprising:

determining that a first network link established via said second physical layer device is down or unreliable;

performing said dynamic switching from said second physical layer device to said first physical layer device in response to said determining.

46. The method of claim 45, wherein said performing said dynamic switching from said. second physical layer device to said first physical layer device includes:

indicating that said first network link is going off-line;

isolating said second physical layer device;

from a link signaling a physical layer interface unit that data transmitted to or received from a link switching unit corresponds to said first physical layer device instead of said second physical layer device;

signaling said link switching unit to begin conveying data to and from said first physical layer device instead of said second physical layer device;

configuring said first physical layer device;

de-isolating said first physical layer device.

47. A network interface device within a computer system, comprising:

a first physical layer interfacing means for establishing a link to a network via a first transmission means;

a second physical layer interfacing means for establishing said link to said network via a second transmission means;

a dynamic switching means for switching between said first physical layer interfacing means and said second physical layer interfacing means in establishing said link to said network;

wherein said first transmission means is a fiber-optic transmission means, and wherein said second transmission means is a non-fiber-optic transmission means;

a first physical layer interface sub-unit means for processing data according to an interface of the first physical layer interfacing means; and

a second physical layer interface sub-unit means for processing data according to an interface of the second physical layer interfacing means.

48. The network interface device of claim 47, wherein said dynamic switching means is further configured to establish said link to said network via only one of said first physical layer interfacing means or said second physical layer interfacing means at a time.