Loss tolerant transmission control protocol

• US 20060251010A1
• 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 7,366,132 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 1/1809 Selective-repeat protocols
• 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 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
• 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: H04W 28/0284 detecting congestion or overload during communication monitoring arrangements H04L43/00
• CPC Class Codes: H04W 28/10 Flow control between communication endpoints
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

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 for transmitting a data window containing packets in a communication network, the data window having a window size, the method comprising the steps of:

estimating a packet erasure rate;

determining a number of proactive FEC packets for the data window based on the estimated packet erasure rate;

determining a packet size for the packets in the data window based on the window size of the data window and the determined number of proactive FEC packets;

transmitting the data window, wherein the packets in the transmitted data window have a size corresponding to the determined packet size and include the determined number of proactive FEC packets.

2. The method of claim 1 wherein the step of estimating a packet erasure rate comprises applying an exponential weighted moving average.

3. The method of claim 1 wherein the step of determining a packet size comprises determining granularity of the window.

4. The method of claim 1 wherein the step of determining a packet size comprises decreasing the packet size for the data packets by a factor f.

5. The method of claim 4 further comprising receiving an Explicit Congestion Notification (ECN), wherein decreasing the packet size for the data packet is responsive to the ECN.

6. The method of claim 1 wherein the transmitted data window contains N data packets and wherein the N is equal to the sum of the number of data packets and the number of determined proactive FEC packets.

7. The method of claim 6 wherein N is determined based on the determined packet size.

8. The method of claim 7 wherein N is further determined based on the window size.

9. The method of claim 1 wherein the step of determining a number of proactive FEC packets comprises setting the number of proactive FEC packets substantially equal to the estimated packet erasure rate.

10. The method of claim 1 wherein the step of determining a number of proactive FEC packets comprises

obtaining an amount of proactive FEC bytes in the data window as the product of the window size and the estimated packet erasure rate;

and,

determining the number of proactive FEC packets as the amount of proactive FEC bytes divided by a current packet size.

11. The method of claim 10 further comprising determining a number of data packets by:

obtaining the amount of data bytes in the data window as the product of the window size and the difference between 1 and the estimated packet erasure rate; and

,

determining the number of data packets as the amount of data bytes in the data window divided by the current packet size.

12. The method of claim 11 wherein the transmitted data window contains the determined number of proactive FEC packets and the determined number of data packets.

13. The method of claim 1 wherein the step of determining a packet size comprises adapting the packet size from a first size to a second size smaller than the first size.

14. The method of claim 13 wherein the step of determining a packet size includes increasing window granularity of the data window.

15. The method of claim 1 further comprising:

receiving a duplicate acknowledgement;

transmitting a reactive FEC packet responsive to the duplicate acknowledgement.

16. The method of claim 15 further comprising determining a number of reactive FEC packets to transmit based on the number of packets expected to be received.

17. The method of claim 15 further comprising determining a number of reactive FEC packets to transmit based on the number of proactive FEC packets expected to be received and the estimated packet erasure rate.

18. The method of claim 1 further comprising adjusting window granularity of the data window.

19. The method of claim 18 wherein the step of adjusting window granularity comprises adjusting the size of the packets in the data window.

20. The method of claim 18 wherein adjusting window granularity is based on the number of proactive FEC packets in the data window.

21. The method of claim 1 further comprising a step of receiving an Explicit Congestion Notification (ECN).