Dynamic header creation and flow control for a programmable communications processor, and applications thereof

• US 8,831,024 B2
• Filed: 12/28/2007
• Issued: 09/09/2014
• Est. Priority Date: 12/29/2006
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Robinson, Michael R., Danzig, Joel I., Johnson, Thomas L.
• Primary Examiner(s): ABELSON, RONALD B
• Application Number:
  US11/966,843
• Publication Number:
  US 20080159140A1
• Time in Patent Office: 2,447 Days
• Field of Search: 370412-418
• US Class Current: 370/412
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/21 using leaky-bucket
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 47/36 by determining packet size, e.g. maximum transfer unit [MTU]
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/901 using storage descriptor, e.g. read or write pointers
• CPC Class Codes: H04L 49/9042 Separate storage for different parts of the packet, e.g. header and payload
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers

Abstract

A method, system and computer program product for creating dynamic custom headers and for controlling flow rate of Downstream External Physical layer Interface (DEPI) packets are described herein. The method comprises concatenating or fragmenting a packet descriptor of a DEPU packet based on one or more of associated packet size, maximum transmission unit, packet type, channel configuration information and flow control mode. The method further comprises creating a header for the packet based on data in a programmable header template and storing the header in a header buffer, determining whether to transmit the packet based on one of a flow meter or a maximum transmission unit size and transmitting the packet by sending the packet descriptor to an output direct memory access (DMA) controller. A flow meter flow control mode determines if a packet is to be transmitted based on packet size, bucket size, a low threshold and a high threshold. A maximum transmission unit flow control mode determines if a packet is to transmitted based on packet size and a maximum transmission unit size. The header can be customized for Packet Streaming Protocol (PSP) mode or Moving Picture Experts Group Transport Stream (MPT) mode and includes dynamic customizable fields such as User Datagram Protocol (UDP) port identification, flow identification and session identification.

Claims

1. A method to determine whether a packet is to be transmitted by a processor, comprising:

determining whether a size of the packet results in a bucket size parameter being above a predetermined low threshold and below a predetermined high threshold;

concatenating the packet with at least one other packet up to a maximum transmission unit size to generate a concatenated packet only if the size of the concatenated packet results in the bucket size parameter being above the predetermined low threshold and below the predetermined high threshold, otherwise sending the packet if the size of the packet results in the bucket size parameter being below the predetermined low threshold; and

sending the concatenated packet when the packet has been concatenated with the at least one other packet up to the maximum transmission unit size,

wherein the bucket size parameter is a parameter that is incremented with a number of bytes in the packet excluding a number of bytes in a header of the packet, and wherein the bucket size parameter is decremented at a rate at which packets are transmitted from an output channel.

2. The method of claim 1, wherein the maximum transmission unit size is programmable via a command from a source external to the processor.

3. The method of claim 1, wherein the packet is in a Packet Streaming Protocol (PSP) format or a Moving Picture Experts Group Transport Stream (MPT) format.

4. The method of claim 1, wherein the low threshold and high threshold values are programmable.

5. The method of claim 1, wherein the packet is stored in one of a high priority, medium priority, or low priority queue.

6. The method of claim 5, wherein each of the high priority, medium priority, and low priority queues has has an associated low threshold and high threshold.

7. The method of claim 1, further comprising:

determining whether there are a sufficient number of other packets for concatenation with the packet up to the maximum transmission unit size.

8. The method of claim 1, further comprising:

fragmenting the packet up to the maximum transmission unit size if the size of the packet is greater than the maximum transmission unit size.

9. The method of claim 8, wherein the packet is fragmented at a 32-bit boundary.

10. The method of claim 9, wherein each fragment of the packet has a payload of at least four bytes.

11. A method to control flow of packets, each packet having a custom header created by a processor, comprising:

concatenating or fragmenting a packet descriptor associated with the packet based on one or more of associated packet size, maximum transmission unit, packet type, channel configuration information and flow control mode;

creating a header for the packet based on data in a programmable header template and storing the header in a header buffer;

determining whether to transmit the packet based on one of a flow meter flow control mode or a maximum transmission unit size flow control mode; and

transmitting the packet by sending the packet descriptor to an output direct memory access (DMA) controller.

12. The method of claim 11, further comprising:

prior to the concatenating or fragmenting step, determining whether there is a packet descriptor available in a DMA status First in First Out (FIFO) queue.

13. The method of claim 12, further comprising:

placing the packet descriptor in one of a plurality of packet descriptor queues based on the priority level of the packet and de-queuing the packet descriptor from the DMA status FIFO queue.

14. The method of claim 13, further comprising:

servicing the plurality of packet descriptor queues in a descending order of priority.

15. The method of claim 11, further comprising:

determined whether at least two vacant entries are present on a descriptor ring storing the packet descriptor prior to fragmenting the packet descriptor.

16. The method of claim 11, wherein the maximum transmission unit is programmable.

17. The method of claim 11, further comprising:

subsequent to the transmitting step, using the packet descriptor for a new incoming packet.

18. The method of claim 11, the determining step further comprising:

using a bucket size parameter, low threshold and high threshold in flow meter flow control mode to determine whether a packet is to be transmitted.

19. The method of claim 11, the determining step further comprising:

using the packet size and the maximum transmission unit size in the maximum transmission unit flow control mode to determine whether a packet is to be transmitted.

20. A method to determine whether a packet is to be transmitted by a processor, comprising:

determining whether a size of the packet results in a bucket size parameter being above a predetermined low threshold and below a predetermined high threshold;

concatenating the packet with at least one other packet up to a maximum transmission unit size to generate a concatenated packet only if the size of the concatenated packet results in the bucket size parameter being above the predetermined low threshold and below the predetermined high threshold, otherwise sending the packet if the size of the packet results in the bucket size parameter being below the predetermined low threshold; and

sending the concatenated packet when the packet has been concatenated with the at least one other packet up to the maximum transmission unit size,

wherein the bucket size parameter is a parameter that is incremented with a number of bytes in the packet excluding a number of bytes in a header of the packet, and wherein the bucket size parameter is decremented at a rate at which packets are transmitted from an output channel.

21. A method to determine whether a packet is to be transmitted by a processor, comprising:

determining whether a size of the packet results in a bucket size parameter being above a predetermined low threshold and below a predetermined high threshold; and

concatenating the packet with at least one other packet up to a maximum transmission unit size to generate a concatenated packet only if the size of the concatenated packet results in the bucket size parameter being above the predetermined low threshold and below the predetermined high threshold, otherwise sending the packet if the size of the packet results in the bucket size parameter being below the predetermined low threshold;

wherein the maximum transmission unit size is programmable via a command from a source external to the processor, and

wherein the bucket size parameter is a parameter that is incremented with a number of bytes in the packet excluding a number of bytes in a header of the packet, and wherein the bucket size parameter is decremented at a rate at which packets are transmitted from an output channel.

22. A method to determine whether a packet is to be transmitted by a processor, comprising:

fragmenting the packet up to a maximum transmission unit size if a size of the packet is greater than the maximum transmission unit size;

determining whether the size of the packet results in a bucket size parameter being above a predetermined low threshold and below a predetermined high threshold; and

concatenating the packet with at least one other packet up to the maximum transmission unit size to generate a concatenated packet only if the size of the concatenated packet results in the bucket size parameter being above the predetermined low threshold and below the predetermined high threshold, otherwise sending the packet if the size of the packet results in the bucket size parameter being below the predetermined low threshold;

wherein the bucket size parameter is a parameter that is incremented with a number of bytes in the packet excluding a number of bytes in a header of the packet, and wherein the bucket size parameter is decremented at a rate at which packets are transmitted from an output channel.