Loss tolerant transmission control protocol

• US 20060251011A1
• Filed: 12/01/2005
• Published: 11/09/2006
• Est. Priority Date: 03/30/2005
• Status: Active Grant

• Current Assignee: AT&T Corporation (AT&T, Inc.), Rensselaer Polytechnic Institute
• Original Assignee: AT&T Corporation (AT&T, Inc.), Rensselaer Polytechnic Institute
• Inventors: Kalyanaraman, Shivkumar, Ramakrishnan, Kadangode K., Tickoo, Omesh, Subramanian, Vijaynarayanan
• Granted Patent: US 7,889,654 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04L 1/0007 by modifying the frame length
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/1635 Cumulative acknowledgement, i.e. the acknowledgement message applying to all previous messages
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/135 by jamming the transmission media
• CPC Class Codes: H04L 47/193 at the transport layer, e.g. TCP related
• CPC Class Codes: H04L 47/27 Evaluation or update of window size, e.g. using information derived from acknowledged [ACK] packets
• CPC Class Codes: H04L 47/365 Dynamic adaptation of the packet size

Abstract

Provided are apparatuses and methods for transmitting or receiving data packets in a data block in a communication network with a transport protocol. In one example, a loss tolerant TCP protocol is used in which a maximum segment size (MSS) may be adapted to a minimum granularity of a congestion window. Also, proactive forward error correction (FEC) packets may be added to a window of the data block. The number of proactive FEC packets may be determined, for example, based on an estimate erasure rate. In addition, reactive FEC packets may be added to the data block. Also, a receiver may receive data packets in a data block and process a selective acknowledgment (SACK) responsive to the data packets received.

Claims

1. A method of transmitting a data block containing a data window of a number of packets, the method comprising the steps of:

setting a loss estimate value;

setting the number of packets in the data window to a first number of packets corresponding to a minimum window granularity, wherein each packet contains a first number of bytes;

setting a block size of the data block to the window size, wherein the number of packets in the block is N;

splitting the N packets in the block into a first group of data packets and a second group of proactive FEC packets based on the loss estimate value; and

transmitting the data block, wherein the data block contains the first group of data packets and the second group of proactive FEC packets.

2. The method of claim 1 further comprising updating the loss estimate value and recalculating the number of data packets and the number of proactive FEC packets based on the updated loss estimate value and the window size.

3. The method of claim 2 further comprising transmitting a second data block comprising the recalculated number of data packets and the recalculated number of proactive FEC packets.

4. The method of claim 2 wherein the step of determining the loss estimate value comprises:

receiving an acknowledgement signal comprising a loss estimate parameter;

updating the loss estimate value based on the loss estimate parameter.

5. The method of claim 4 wherein the first number of packets is based on minimum window granularity.

6. The method of claim 3 wherein the first number of bytes is based on a predetermined minimum size of a packet.

7. The method of claim 1 wherein the step of setting the block size comprises:

obtaining a size of the data window;

determining the number of packets capable of being accommodated in the data window based on the size of the data window;

updating the number of packets capable of being accommodated in the data window;

setting N equal to a number of packets corresponding to the updated number of packets.

8. The method of claim 7 wherein the step of determining the number of packets capable of being accommodated in the data window comprises:

determining a first value corresponding to the maximum size of a packet; and

dividing the size of the data window by the first value.

9. The method of claim 8 wherein the first value is 1500 bytes.

10. The method of claim 7 wherein the step of updating the number of packets comprises:

decreasing the value of a first value corresponding to the maximum size of a packet by a predetermined amount; and

dividing the size of the data window by the decreased first value.

11. The method of claim 10 wherein the decreasing and dividing steps are performed only if the first value is less than or equal to a minimum window granularity.

12. The method of claim 11 wherein the predetermined amount is about 50 bytes.

13. The method of claim 7 further comprising repeating the updating step.

14. The method of claim 13 further comprising repeating the updating step until the first value is greater than the minimum window granularity.

15. The method of claim 7 wherein the step of determining the number of packets comprises:

determining a first value corresponding to the maximum size of a packet; and

dividing the size of the data window by the first value, and wherein the step of updating the number of packets comprises;

decreasing the value of the first value by a predetermined amount; and

dividing the size of the data window by the decreased first value if the first value is less than or equal to a minimum window granularity,

and wherein the updating step is repeated until the first value is greater than the minimum window granularity.

16. The method of claim 1 wherein the step of setting the block size comprises:

obtaining a maximum segment size (MSS) of the data window;

determining the number of packets capable of being accommodated in the data window based on the MSS;

updating the number of packets capable of being accommodated in the data window;

providing a data window containing a number of packets corresponding to the updated number of packets.

17. The method of claim 16 wherein the step of determining the number of packets capable of being accommodated in the data window comprises:

determining a first value corresponding to the MSS; and

dividing the size of the data window by the first value.

18. The method of claim 16 wherein the step of updating the number of packets capable of being accommodated in the data window comprises:

incrementing a first value corresponding to the MSS by a predetermined amount; and

dividing the size of the data window by the incremented first value.

19. The method of claim 18 wherein the predetermined amount corresponds to a number of bytes by which the MSS is capable of being increased in one pass.

20. The method of claim 18 wherein the predetermined amount is about 200 bytes.

21. The method of claim 18 wherein the step of updating the number of packets further comprises setting the MSS to the incremented first value if the updated number of packets capable of being accommodated in the data window is less than the minimum window granularity and the incremented first value is less than or equal to a maximum size of a packet in the data window.

22. The method of claim 16 wherein the step of determining the number of packets capable of being accommodated in the data window comprises:

determining a first value corresponding to the MSS; and

dividing the size of the data window by the first value,

and wherein the step of updating the number of packets capable of being accommodated in the data window comprises;

incrementing a first value corresponding to the MSS by a predetermined amount;

dividing the size of the data window by the incremented first value; and

setting the MSS to the incremented first value if the updated number of packets capable of being accommodated in the data window is less than a minimum window granularity and the incremented first value is less than or equal to a maximum size of a packet in the data window.