System and method for dropping lower priority packets that are slated for transmission

• US 7,839,785 B2
• Filed: 09/25/2002
• Issued: 11/23/2010
• 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: Gomez, Francisco J, Vu, Young, Pantelias, Niki, Lansing, Shane
• Primary Examiner(s): Tran; Phuc H.
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US10/253,659
• Publication Number:
  US 20030058795A1
• Time in Patent Office: 2,981 Days
• Field of Search: 370/235, 370/363, 370/368, 370/371, 370/374, 370/378, 370/381, 370/412, 370/413, 370/428, 370/429, 370/395.72, 370/395.7
• US Class Current: 370/235
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 12/4604 LAN interconnection over a backbone network, e.g. Internet, Frame Relay
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/2441 relying on flow classification, e.g. using integrated services [IntServ]
• CPC Class Codes: H04L 47/28 in relation to timing considerations
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04W 28/02 Traffic management, e.g. flow control or congestion control
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

A method and system for dropping lower priority packets for transmission over a communication medium is provided. A cable modem termination system receives one or more packets to be transferred to one or more data providers, each packet having a priority. Then, based on the priority, a media access controller stores each of the packets in one or more priority queues in a fixed shared memory space in such a way as to maintain the order in which the packets were received in each of the priority queues. The media access controller monitors the number of packets in each of the priority queues and signals an interrupt when a packet threshold is exceeded in one or more of the priority queues. The media access controller then drops lower priority packets in the fixed shared memory space based on the order received to guarantee that there is enough memory to store higher priority packets in the fixed shared memory space.

Claims

1. A method for dropping lower priority packets that are slated for transmission over a communication medium, comprising the steps of:

receiving one or more packets to be transferred to one or more data providers, each packet having a priority;

based on the priority, storing each of the packets in priority queues in a fixed shared memory space in such a way as to maintain the order in which the packets were received in each of the priority queues, wherein all packets stored in any one of the priority queues have the same priority;

monitoring the number of packets in each of the priority queues and signaling an interrupt when a packet threshold is exceeded in one of the priority queues; and

in response to the interrupt being signaled, dropping lower priority packets in a plurality of the priority queues to free up space for higher priority packets to be stored in a second one of the priority queues.

2. The method of claim 1, wherein the communication medium is cable TV.

3. The method of claim 1, wherein the communication medium is wireless.

4. The method of claim 1, wherein the communication medium is satellite based network.

5. The method of claim 1, wherein the communication medium is the Internet.

6. The method of claim 1, wherein the order is priority first come first served.

18. The method of claim 1, wherein packets are dropped from the plurality of the priority queues based on order received.

7. A system for dropping lower priority packets that are slated for transmission over a communication medium, comprising:

a cable modem termination system for receiving one or more packets to be transferred to one or more data providers, each packet having a priority;

based on the priority, a media access controller for storing each of the packets in priority queues in a fixed shared memory space in such a way as to maintain the order in which the packets were received in each of the priority queues, wherein all packets stored in any one of the priority queues have the same priority;

wherein the media access controller monitors the number of packets in each of the priority queues and signals an interrupt when a packet threshold is exceeded in one of the priority queues;

wherein the media access controller drops lower priority packets in the fixed shared memory space based on the order received; and

wherein lower priority packets stored in a plurality of the priority queues are dropped, in response to the interrupt being signaled, from the fixed shared memory space to free up space for higher priority packets to be stored in the priority queues.

8. The system of claim 7, wherein the communication medium is cable TV.

9. The system of claim 7, wherein the communication medium is wireless.

10. The system of claim 7, wherein the communication medium is satellite based network.

11. The system of claim 7, wherein the communication medium is the Internet.

12. The system of claim 7, wherein the order is priority first come first served.

13. The system of claim 7, further comprising:

a drop begin register configured to indicate when packets should be dropped from the plurality of the priority queues in the fixed shared memory space.

14. The system of claim 7, further comprising:

a threshold value register, a descriptor count register, and a packet drop register for at least two of the priority queues in the fixed shared memory space.

15. The system of claim 14, wherein the threshold value register is configured to indicate a number of packets permitted to be stored in a corresponding priority queue before the interrupt is to be signaled.

16. The system of claim 14, wherein the descriptor count register is configured to indicate a number of packets currently stored in a corresponding priority queue such that the media access controller can determine when a number of packets permitted to be stored in the corresponding priority queue has been exceeded and the interrupt is to be signaled.

17. The system of claim 14, wherein the packet drop register is configured to store the number of packets to drop from a corresponding priority queue in response to the interrupt being signaled.