Highly integrated media access control

• US 7,835,398 B2
• Filed: 08/17/2007
• Issued: 11/16/2010
• 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): Ngo; Ricky
• Assistant Examiner(s): SAMUEL, DEWANDA A
• Application Number:
  US11/892,025
• Publication Number:
  US 20080046952A1
• Time in Patent Office: 1,187 Days
• Field of Search: 370/403, 370/432, 370/474
• 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 communications network, monitors and controls communications with a plurality of remote communications devices 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 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. A method for processing signals within a media access controller integrated circuit (MAC IC), comprising:

(a) receiving a signal from a physical layer device coupled to the MAC IC, the physical layer device being operable for communication over a wireless medium;

(b) pre-processing a header within the signal, the pre-processing including;

(i) decrypting the signal after receiving key information to provide decryption match information identifying whether a sequence number within the header and the key information match,

(ii) comparing the header with a stored header value retrieved using the key information to detect a header type to provide header match information identifying whether the header type and the stored header value match,

(iii) extracting one or more payloads from the signal based upon the header type, and

(c) detecting one or more fragmented frames from the signal; and

(d) reassembling the one or more fragmented frames to produce a reassembled frame in response to the detecting the one or more fragmented frames.

2. The method of claim 1, wherein step (b)(i) comprises:

(b)(i)(A) extracting decryption information from the header to determine whether the data decryption is to be performed.

3. The method of claim 2, wherein the decryption information includes information relating to a baseline privacy interface (BPI) field within the header.

4. The method of claim 3, wherein step (b)(i) further comprises:

(b)(i)(B) decrypting the signal when the BPI field is enabled.

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

6. The method of claim 1, wherein step (b)(ii) comprises:

(b)(ii)(A) comparing the header with the stored header value retrieved using the key information to detect the header type when the signal includes an Unsolicited Grant Service (UGS) extended header.

7. The method of claim 1, wherein step (b)(ii) comprises:

(b)(ii)(A) sending a request to update the stored header value when the header type and the stored header value do not match.

8. The method of claim 1, wherein step (b)(ii) further comprises:

accumulating the decryption match information and the header match information.

9. The method of claim 1, wherein step (b) further comprises:

(b)(iv) prioritizing the signal; and

(b)(v) detecting errors within the signal based upon the header.

10. The method of claim 9, wherein step (b)(v) comprises:

(b)(v)(A) checking 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.

11. The method of claim 1, wherein step (d) comprises:

(d)(i) terminating reassembly of the one or more fragmented frames upon detection of one or more error conditions; and

(d)(ii) discarding the one or more fragmented frames that caused the one or more error conditions.

12. The method of claim 11, wherein the one or more error conditions include at least one of a group consisting of:

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.

13. An apparatus for processing signals within a media access controller integrated circuit (MAC IC), comprising:

a physical layer device configured to receive a signal over a wireless medium;

an egress processor configured to pre-process a header within the signal, the egress processor including;

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

a header processor configured to compare the header with a stored header value retrieved using the key information to detect a header type to provide header match information identifying whether the header type and the stored header value match and to extract the one or more payloads from the signal based upon the header type, and

a fragment reassembly controller configured to detect one or more fragmented frames from the signal and to reassemble the one or more fragmented frames to produce a reassembled frame.

14. The apparatus of claim 13, wherein the decrypt module is further configured to extract decryption information from the header to determine whether the data decryption is to be performed.

15. The apparatus of claim 14, wherein the decryption information includes information relating to a baseline privacy interface (BPI) field within the header.

16. The apparatus of claim 14, wherein the decrypt module is further configured to decrypt the signal when the BPI field is enabled.

17. The apparatus of claim 13, wherein the decryption match information indicates the sequence number and the key information do not substantially match.

18. The apparatus of claim 13, wherein the header processor is configured to compare the header with the stored header value retrieved using the key information to detect the header type when the signal includes an Unsolicited Grant Service (UGS) extended header.

19. The apparatus of claim 13, herein the header processor is further configured to send a request to update the stored header value when the header type and the stored header value do not match.

20. The apparatus of claim 13, wherein the egress processor further includes:

a request queue direct memory access (DMA) controller egress processor configured to accumulate the decryption match information and the header match information.

21. The apparatus of claim 13, wherein the egress processor further includes:

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

22. The apparatus of claim 21, 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.

23. The apparatus of claim 13, 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.

24. The apparatus of claim 23, wherein the one or more error conditions include at least one of a group consisting of:

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.