Method and apparatus for negotiating link speed and configuration

1. A method for negotiating link speed and configuration, the method comprising:

transmitting during an idle period a modulated output Z comprising a modulation of a data D and a sequence of IDLE signals across a link for a predetermined time amount;

prior to transmitting the modulated output Z, performing a modulation of the data D with contents of a synchronous scrambler at a first node in order to generate the modulated output Z, where the data D includes configuration information and where the data D is modulated by performing a first XOR logic operation with the data D and with a first XOR logic function of contents of the synchronous scrambler;

demodulating the modulated output Z with the contents of a synchronous descrambler at a second node in order to recover the data D, where the modulated output Z is demodulated by performing a second XOR logic operation with the modulated output Z and with a second XOR logic function of contents of the synchronous descrambler; and

based on the configuration information in the data D recovered from the demodulated output Z, setting, by the first node and the second node, negotiated configuration settings for operations on the link.

2. The method of claim 1 , wherein the act of performing the modulation comprises:

performing the exclusive-OR operation on the data D and with the first XOR logic function of bits D[ 5 ] and D[ 6 ] in the contents of the synchronous scrambler.

3. The method of claim 2 , wherein the contents of the synchronous scrambler is obtained from bit D[ 5 ] and bit D[ 6 ] of the synchronous scrambler.

4. The method of claim 1 , wherein the act of demodulating the modulated output Z comprises:

performing the exclusive-OR operation on the modulated output Z with the second XOR logic function of bits D[ 5 ] and D[ 6 ] in the contents of the synchronous descrambler.

5. The method of claim 4 , wherein the contents of the synchronous descrambler is obtained from bit D[ 5 ] and bit D[ 6 ] of the synchronous descrambler.

6. The method of claim 1 , wherein the data D is sent at a pre-selected clock rate.

7. The method of claim 6 , wherein the clock rate is approximately 312.5 MHz+100 ppm.

8. The method of claim 1 , wherein the modulated output Z is encoded by symbol encoded.

9. The method of claim 1 , wherein one of the nodes receiving the modulated output Z includes the 10 Gigabit Ethernet (XAUI) interface.

10. The method of claim 1 , wherein the configuration information is conveyed by use of IDLE signals.

11. The method of claim 1 , wherein the configuration information is conveyed by use of a link status value /Q/.

12. An apparatus for negotiating link speed and configuration, the apparatus comprising:

a first node including a synchronous scrambler, the node configured to transmit during an idle period a modulated output Z comprising a modulation of a data D and a sequence of IDLE signals across a link for a predetermined time amount and configured to perform a modulation of the data D with contents of the synchronous scrambler in order to generate the modulated output Z prior to transmitting the modulated output Z, where the data D includes configuration information and where the data D is modulated by performing a first XOR logic operation with the data D and with a first XOR logic function of contents of the synchronous scrambler;

a second node including a synchronous descrambler;

wherein the link is coupled to the first node and the second node;

wherein the second node is configured to demodulate the modulated output Z with the contents of the synchronous descrambler in order to recover the data D, where the modulated output Z is demodulated by performing a second XOR logic operation with the modulated output Z and with a second XOR logic function of contents of the synchronous descrambler; and

wherein based on the configuration information in the data D recovered from the demodulated output Z, the first node and the second node are configured to set negotiated configuration settings for operations on the link.

13. The apparatus of claim 12 , wherein the first node performs the modulation by performing the exclusive-OR operation on the data D and with the first XOR logic function of bits D[ 5 ] and D[ 6 ] of the contents of the synchronous scrambler.

14. The apparatus of claim 13 , wherein the contents of the synchronous scrambler is obtained from bit D[ 5 ] and bit D[ 6 ] of the synchronous scrambler.

15. The apparatus of claim 12 , wherein the second node performs the demodulation of the modulated output Z by performing the exclusive-OR operation on the modulated output Z with the second XOR logic function of bits D[ 5 ] and D[ 6 ] in the contents of the synchronous descrambler.

16. The apparatus of claim 15 , wherein the contents of the synchronous descrambler is obtained from bit D[ 5 ] and bit D[ 6 ] of the synchronous descrambler.

17. The apparatus of claim 12 , wherein the data D is sent at a pre-selected clock rate.

18. The apparatus of claim 17 , wherein the clock rate is approximately 312.5 MHz+100 ppm.

19. The apparatus of claim 12 , wherein the modulated output Z is encoded by symbol encoded.

20. The apparatus of claim 12 , wherein one of the nodes receiving the modulated output Z includes the 10 Gigabit Ethernet (XAUI) interface.

21. The apparatus of claim 12 , wherein the configuration information is conveyed by use of IDLE signals.

22. The apparatus of claim 12 , wherein the configuration information is conveyed by use of a link status value /Q/.

23. An apparatus for negotiating link speed and configuration, the apparatus comprising:

means for transmitting during an idle period a modulated output Z comprising a modulation of a data D and a sequence of IDLE signals across a link for a predetermined time amount, wherein the modulated output Z comprises the data D modulated onto the IDLE signals;

means for performing a modulation of the data D with contents of a synchronous scrambler at a first node in order to generate the modulated output Z prior to transmitting the modulated output Z, where the data D includes configuration information and where the data D is modulated by performing a first XOR logic operation with the data D and with a first XOR logic function of contents of the synchronous scrambler;

means for demodulating the modulated output Z with the contents of a synchronous descrambler at a second node in order to recover the data D, where the modulated output Z is demodulated by performing a second XOR logic operation with the modulated output Z and with a second XOR logic function of contents of the synchronous descrambler; and

wherein based on the configuration information in the data D recovered from the demodulated output Z, the first node and the second node are configured to set negotiated configuration settings for operations on the link.

24. The method of claim 1 , wherein the modulation of the data D is performed if the sequence of IDLE signals comprises a skip code.

25. The method of claim 1 , wherein the modulation of the data D is performed if the sequence of IDLE signals comprises a symbol indicating lane synchronization.

26. The method of claim 1 , wherein the modulation of the data D is not performed if the sequence of IDLE signals comprises a control word that is used to accomplish lane alignment.

27. The method of claim 1 , wherein the demodulation of the data D is performed if the sequence of IDLE signals comprises a skip code.

28. The method of claim 1 , wherein the demodulation of the data D is performed if the sequence of IDLE signals comprises a symbol indicating lane synchronization.

29. The method of claim 1 , wherein the demodulation of the data D is not performed if the sequence of IDLE signals comprises a control word that is used to accomplish lane alignment.

30. The apparatus of claim 12 , wherein the first node performs modulation of the data D if the sequence of IDLE signals comprises a skip code.

31. The apparatus of claim 12 , wherein the first node performs modulation of the data D if the sequence of IDLE signals comprises a symbol indicating lane synchronization.

32. The apparatus of claim 12 , wherein the first node does not perform modulation of the data D if the sequence of IDLE signals comprises a control word that is used to accomplish lane alignment.

33. The apparatus of claim 12 , wherein the second node performs demodulation of the data D if the sequence of IDLE signals comprises a skip code.

34. The apparatus of claim 12 , wherein the second node performs demodulation of the data D if the sequence of IDLE signals comprises a symbol indicating lane synchronization.

35. The apparatus of claim 12 , wherein the second node does not perform demodulation of the data D if the sequence of IDLE signals comprises a control word that is used to accomplish lane alignment.

36. The apparatus of claim 23 , wherein the means for performing the modulation performs modulation of the data D if the sequence of IDLE signals comprises a skip code.

37. The apparatus of claim 23 , wherein the means for performing the modulation performs modulation of the data D if the sequence of IDLE signals comprises a symbol indicating lane synchronization.

38. The apparatus of claim 23 , wherein the means for performing the modulation does not perform modulation of the data D if the sequence of IDLE signals comprises a control word that is used to accomplish lane alignment.

39. The apparatus of claim 23 , wherein the means for demodulating performs demodulation of the data D if the sequence of IDLE signals comprises a skip code.

40. The apparatus of claim 23 , wherein the means for demodulating performs demodulation of the data D if the sequence of IDLE signals comprises a symbol indicating lane synchronization.

41. The apparatus of claim 23 , wherein the means for demodulating does not perform demodulation of the data D if the sequence of IDLE signals comprises a control word that is used to accomplish lane alignment.