Data packet congestion management technique

• US 6,990,073 B1
• Filed: 03/28/2001
• Issued: 01/24/2006
• Est. Priority Date: 03/28/2001
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: LSI Logic Corporation (Broadcom, Inc.)
• Inventors: Sandoval, Jesse
• Primary Examiner(s): Pezzlo, John
• Assistant Examiner(s): Levitan, Dmitry
• Application Number:
  US09/820,477
• Time in Patent Office: 1,763 Days
• Field of Search: 370229-236
• US Class Current: 370/232
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/193 at the transport layer, e.g. TCP related
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures

Abstract

A circuit for use in a data packet transmission system. The circuit generally comprises a buffer and a test circuit. The buffer may be configured to store a plurality of data packets. The test circuit may be configured to (i) monitor a number of the plurality of data packets in the buffer, (ii) permit an additional data packet to the plurality of data packets into the buffer responsive to the number being less than a first threshold, and (iii) discard the additional data packet in accordance with a probabilistic test responsive to the number being greater than the first threshold.

Claims

1. A circuit comprising:

a buffer for storing a plurality of data packets; and

a test circuit configured to;

(i) monitor a number of said plurality of data packets in said buffer, (ii) receive an additional data packet to said plurality of data packets, (iii) store said additional data packet into said buffer responsive to said number being less than a first threshold, (iv) discard said additional data packet in accordance with a probabilistic test responsive to said number being greater than said first threshold, and (v) presenting an identification signal to a sender of said additional data packet, indicating that said additional data packet was discarded and can be resent.

2. The circuit according to claim 1, wherein said test circuit is further configured to always discard said additional data packet without storing said additional data packets in said buffer in response to said number being at least as great as a second threshold.

3. The circuit according to claim 2, wherein said test circuit is further configured to present a rate signal to a sender of said additional data packets in a stop transmission condition in response to said number being greater than said second threshold.

4. The circuit according to claim 1, wherein said test circuit is further configured to present a rate signal to said sender in a slow rate condition in response to said number being greater than said first threshold.

5. The circuit according to claim 4, wherein said test circuit is further configured to present said rate signal to said sender in a full rate condition in response to said number being less than said first threshold.

6. The circuit according to claim 1, wherein said probabilistic test is based upon a precedence.

7. The circuit according to claim 1, wherein said probabilistic test is based upon a priority.

8. The circuit according to claim 1, wherein said probabilistic test is based upon a volume rate.

9. The circuit according to claim 1, wherein said number is a time average of said data packets in said buffer.

10. The circuit according to claim, 9, wherein said test circuit is further configured to (i) discard said additional data packet in response to said number being at least as great as a second threshold, (ii) present a rate signal in a first condition in response to said number being greater than said first threshold, and (iii) present said rate signal in a second condition in response to said number being less than said first threshold.

11. The circuit according to claim 9, wherein said number is determined before said additional data packet is permitted into said buffer.

12. The circuit according to claim 1, further comprising a queuing management circuit disposed between said buffer and an output and configured to transfer said data from said buffer to said output.

13. A method for managing congestion of a plurality of data packets in a buffer of a circuit, comprising the steps of:

(A) monitoring a number of said plurality of packets in said buffer;

(B) receiving an additional data packet to said plurality of data packets;

(C) storing said additional data packet into said buffer in response to said number being less than a first threshold;

(D) discarding said additional data packet in accordance with a probabilistic test without said additional data packets reaching said buffer in response to said number being greater than said first threshold; and

(E) presenting an identification signal from said circuit to a sender of said additional data packet, said identification signal indicating that said additional data packet was discarded and can be resent.

14. The method according to claim 13, further comprising the step of:

always discarding said additional data packet in response to said number being at least as great as a second threshold.

15. The method according to claim 14, further comprising the step of:

presenting a rate signal to a sender of said additional data packets in a stop transmission condition in response to said number being greater than said second threshold.

16. The method according to claim 13, further comprising the step of:

presenting a rate signal to said sender in a slow rate condition in response to said number being greater than said first threshold.

17. The method according to claim 16, further comprising the step of:

presenting said rate signal to said sender in a full rate condition in response to said number being less than said first threshold.

18. The method according to claim 13, further comprising the step of:

time averaging said number prior to step (C).

19. A circuit comprising:

means for monitoring a number of a plurality packets in a buffer;

means for receiving an additional data packet plurality of data packets;

means for storing said additional data packet into said buffer in response to said number being less than a first threshold;

means for discarding said additional data packet without storing said additional data packets in said buffer in accordance with a probabilistic test in response to said number being greater than said first threshold; and

means for presenting an identification signal from said circuit to a sender of said additional data packet, said identification signal indicating that said additional data packet was discarded and can be resent.

20. The circuit according to claim 19, further comprising means for managing presentation of said data packets from said buffer to an output.