Highly integrated media access control

• US 7,715,437 B2
• Filed: 09/26/2002
• Issued: 05/11/2010
• Est. Priority Date: 09/27/2001
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Pantelias, Niki Roberta, Denney, Lisa Voigt, Horton, John Daniel Jr., Nazareth, Sean Francis, Moshar, Hooman, Lansing, Shane Patrick
• Primary Examiner(s): Pham; Chi H.
• Assistant Examiner(s): MEW, KEVIN D
• Application Number:
  US10/254,764
• Publication Number:
  US 20030061623A1
• Time in Patent Office: 2,784 Days
• Field of Search: 370/474, 370/465, 370/466, 370/469, 370/476, 370/389, 370/392, 370/394, 370/412, 370/428, 370/429
• US Class Current: 370/474
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04L 47/52 by attributing bandwidth to queues
• CPC Class Codes: H04L 47/6215 Individual queue per QOS, rate or priority
• CPC Class Codes: H04L 49/9094 Arrangements for simultaneous transmit and receive, e.g. simultaneous reading/writing from/to the storage element
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications

Abstract

A supervisory communications device, such as a headend device within a cable communications network, monitors and controls communications with a plurality of remote communications devices, such as cable modems, throughout a widely distributed network. The supervisory device allocates bandwidth on the upstream channels by sending MAP messages over its downstream channel. A highly integrated media access controller integrated circuit (MAC IC) operates within the headend to provide lower level DOCSIS processing on signals exchanged with the remote devices. The enhanced functionality of the MAC IC relieves the processing burden on the headend CPU and increases packet throughput. The enhanced functionality includes header suppression and expansion, DES encryption and decryption, fragment reassembly, concatenation, and DMA operations.

Claims

1. An apparatus to process egress signals within a media access controller integrated circuit (MAC IC), comprising:

an egress pre-processor configured to perform preliminary signal processing on a signal to provide one or more payloads, the egress pre-processor including;

a decrypt module configured to perform data decryption on the signal after receiving key information and to provide decryption match information identifying whether a sequence number within a header within the signal and the key information match,

a header processor configured to receive the signal from the decrypt module and to process the header to extract the one or more payloads from the signal, and

a request queue direct memory access (DMA) controller configured to accumulate the decryption match information; and

a fragment reassembly controller configured to identify one or more fragmented frames from the one or more payloads and to reassemble the one or more fragmented frames.

2. The apparatus of claim 1, wherein the decrypt module is configured to perform data decryption on the signal using at least one of a group consisting of:

baseline privacy interface (BPI) protocol, security system interface (SSI), and removable security module interface (RSMI).

3. The apparatus of claim 1, wherein the decrypt module is configured to extract decryption information to determine whether the data decryption is to be performed.

4. The apparatus of claim 3, wherein the decryption information includes information relating to a baseline privacy interface (BPI) field within the header.

5. The apparatus of claim 4, wherein the decrypt module performs the data decryption on the signal when the BPI field is enabled.

6. The apparatus of claim 1, further comprising:

an engress lookup controller configured to provide the key information to the decrypt module.

7. The apparatus of claim 1, wherein the decrypt module is configured to provide the decryption match information by comparing a baseline privacy interface (BPI) sequence number within the header and the key information.

8. The apparatus of claim 1, wherein the decryption match information indicates the sequence number and the key information do not substantially match.

9. The apparatus of claim 1, wherein the egress pre-processor and the fragment reassembly controller are formed as part of a single integrated circuit (IC).

10. The apparatus of claim 1, wherein one or more of the decrypt module, the header processor, the request direct memory access (DMA) controller, and the egress pre-processor are formed as part of a distinct secondary integrated circuit (IC), said distinct secondary being configured to be mounted on a primary IC.

11. The apparatus of claim 1, wherein the egress pre-processor further includes:

a header detector module configured to receive the signal from the decrypt module and to determine whether header comparison is to be performed.

12. The apparatus of claim 11, wherein the header detector module is configured to perform the header comparison when the signal includes an Unsolicited Grant Service (UGS) extended header.

13. The apparatus of claim 11, wherein the header detector module is configured to compare the header within the signal with a stored header value retrieved using the key information when the header comparison is to be performed.

14. The apparatus of claim 13, wherein the header detector module is configured to send a request to update the stored header value when the header type and the stored header value do not match.

15. The apparatus of claim 13, wherein the header detector module is configured to provide header match information, the header match information indicating whether the header type and the stored header value match.

16. The apparatus of claim 15, wherein the request queue DMA controller is configured to accumulate the header match information.

17. The apparatus of claim 1, wherein the header processor is configured perform deconcatenation on the signal to provide the one or more payloads.

18. The apparatus of claim 1, wherein the header processor is configured to extract one or more requests from the signal.

19. The apparatus of claim 18, wherein request queue (DMA) controller is configured to provide at least one of a group consisting of the one or more requests and the decryption match information to a memory.

20. The apparatus of claim 1, wherein the egress pre-processor includes:

a physical layer interface (PHY I/F) configured to prioritize the signal and to detect errors within the signal based upon the header.

21. The apparatus of claim 20, wherein the PHY I/F is configured to check at least one of a group consisting of:

a header checksum (HCS) field and a cyclic redundancy check (CRC) field in the signal to detect the errors.

22. The apparatus of claim 1, wherein the fragment reassembly controller is configured to terminate reassembly of the one or more fragmented frames upon detection of one or more error conditions and to discard the one or more fragmented frames that caused the one or more error conditions.

23. The apparatus of claim 22, wherein the one or more error conditions include one or more missing fragments from among the one or more fragmented frames and one or more out of sequence fragments from among the one or more fragmented frames.

24. The apparatus of claim 1, wherein the fragment reassembly controller is configured to reassemble the one or more fragmented frames to provide one or more defragmented frames, the apparatus further comprising:

a burst DMA configured to provide the one or more defragmented frames to a memory.

47. The apparatus of claim 24, wherein the fragment reassembly controller is configured to reassemble the one or more fragmented frames to provide one or more defragmented frames, the apparatus further comprising:

a burst DMA configured to provide the one or more defragmented frames to a memory.

25. An apparatus to process egress signals within a media access controller integrated circuit (MAC IC), comprising:

an egress pre-processor configured to perform preliminary signal processing on a signal to provide one or more payloads, the egress pre-processor including;

a header detector module configured to compare a header within the signal with a stored header value retrieved using key information to detect a header type and to provide header match information identifying whether the header type and the stored header value match,

a header processor configured to receive the signal from the header detector module and to process the header to extract the one or more payloads from the signal, and

a request queue direct memory access (DMA) controller configured to accumulate the header match information; and

a fragment reassembly controller configured to identify one or more fragmented frames from the one or more payloads and to reassemble the one or more fragmented frames.

26. The apparatus of claim 25, wherein the header detector module is configured determine whether header comparison is to be performed.

27. The apparatus of claim 26, wherein the header detector module is configured to perform the header comparison when the signal includes an Unsolicited Grant Service (UGS) extended header.

28. The apparatus of claim 25, wherein the header detector module is configured to send a request to update the stored header value when the header type and the stored header value do not match.

29. The apparatus of claim 25, further comprising:

an engress lookup controller configured to provide the key information to the header detector module.

30. The apparatus of claim 25, wherein the egress pre-processor and the fragment reassembly controller are formed as part of a single integrated circuit (IC).

31. The apparatus of claim 25, wherein one or more of the header detector module, the header processor, the request direct memory access (DMA) controller, and the egress pre-processor are formed as part of a distinct secondary integrated circuit (IC), said distinct secondary being configured to be mounted on a primary IC.

32. The apparatus of claim 25, wherein the egress pre-processor further includes:

a decrypt module configured to perform data decryption on the sigual after the receiving key information and to provide decryption match information identifying whether a sequence number within a header within the signal and the key information match.

33. The apparatus of claim 32, wherein the decrypt module is configured to perform data decryption on the signal using at least one of a group consisting of:

baseline privacy interface (BPI) protocol, security system interface (SSI), and removable security module interface (RSMI).

34. The apparatus of claim 32, wherein the decrypt module is configured to extract decryption information to determine whether the data decryption is to be performed.

35. The apparatus of claim 34, wherein the decryption information includes information relating to a baseline privacy interface (BPI) field within the header.

36. The apparatus of claim 35, wherein the decrypt module performs the data decryption on the signal when the BPI field is enabled.

37. The apparatus of claim 32, wherein the decrypt module is configured to provide the decryption match information by comparing a baseline privacy interface (BPI) sequence number within the header and the key information.

38. The apparatus of claim 32, wherein the decryption match information indicates the sequence number and the key information do not substantially match.

39. The apparatus of claim 32, wherein the request queue DMA controller is configured to accumulate the decryption match information.

40. The apparatus of claim 25, wherein the header processor is configured perform deconcatenation on the signal to provide the one or more payloads.

41. The apparatus of claim 25, wherein the header processor is configured to extract one or more requests from the signal.

42. The apparatus of claim 41, wherein request queue (DMA) controller is configured to provide at least one of a group consisting of the one or more requests and the decryption match information to a memory.

43. The apparatus of claim 25, wherein the egress pre-processor includes:

a physical layer interface (PHY I/F) configured to prioritize the signal and to detect errors within the signal based upon the header.

44. The apparatus of claim 43, wherein the PHY I/F is configured to check at least one of a group consisting of:

a header checksum (HCS) field and a cyclic redundancy check (CRC) field in the signal to detect the errors.

45. The apparatus of claim 25, wherein the fragment reassembly controller is configured to terminate reassembly of the one or more fragmented frames upon detection of one or more error conditions and to discard the one or more fragmented frames that caused the one or more error conditions.

46. The apparatus of claim 45, wherein the one or more error conditions include one or more missing fragments from among the one or more fragmented frames and one or more out of sequence fragments from among the one or more fragmented frames.