Wavefront detection and disambiguation of acknowledgments

• US 20050058131A1
• Filed: 07/28/2004
• Published: 03/17/2005
• Est. Priority Date: 07/29/2003
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Orbital Data Corporation (Cloud Software Group)
• Inventors: Samuels, Allen R., Sutter, Paul G.
• Granted Patent: US 7,616,638 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 41/00 Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/34 ensuring sequence integrity, e.g. using sequence numbers
• CPC Class Codes: H04L 67/2876 Pairs of inter-processing entities at each side of the network, e.g. split proxies
• CPC Class Codes: H04L 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54
• 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 69/166 IP fragmentation; TCP segmentation

Abstract

One or more flow control modules, implemented on various types of network topologies, provide a number of functionalities for controlling the flow of IP packets (such as TCP/IP packets) over a network connection. The flow control modules may be implemented within a sender and/or receiver or may be deployed into a network as a separate device without requiring significant additional resources.

Claims

1. A method for communicating with a remote system using Internet Protocol (IP) via a computer network, the method comprising:

transmitting a data packet to the remote system;

retransmitting the data packet to the remote system;

receiving an acknowledgement packet indicating that the data packet was received by the remote system, the acknowledgement packet identifying the data packet; and

associating the acknowledgement packet with either the transmission or the retransmission of the data packet, based on identifying information in the acknowledgement packet, thereby determining whether the transmission or the retransmission of the data packet was received and acknowledged by the remote system.

2. The method of claim 1, further comprising:

presuming lost any data packets that (1) have not been acknowledged and (2) were transmitted before the acknowledged transmission or retransmission of the data packet; and

retransmitting the presumed lost data packets.

3. The method of claim 1, wherein each instance of the transmission and the retransmission of the data packet includes a unique identifier, and the identifying information in the acknowledgement packet is a function of the identifier.

4. The method of claim 3, wherein the identifying information includes the identifier.

5. The method of claim 3, wherein the identifier is a time stamp.

6. The method of claim 3, wherein the data packet conforms to the TCP/IP protocol, and the identifying information is included in an IP ID field of the data packet.

7. The method of claim 6, wherein the identifying information in the acknowledgement packet comprises the identifier in an IP ID field of the acknowledgement packet with a most significant bit reversed.

8. The method of claim 1, wherein the associating is performed in a flow control module coupled to the sender.

9. A method for transmitting data packets to a receiver over a network, the method comprising:

transmitting a plurality of data packets to the receiver;

retransmitting a number of the transmitted data packets responsive to an indication that the retransmitted data packets were not received by the receiver;

maintaining a unique transmit number for each instance of a transmitted or retransmitted data packet;

receiving acknowledgements indicating that at least some of the data packets have been received; and

a step for disambiguating the received acknowledgements to determine for each ambiguous acknowledgement the instance of transmitted or retransmitted data packet to which the ambiguous acknowledgement relates.

10. The method of claim 9, further comprising:

for each received acknowledgment, presuming lost any data packets that were transmitted before the acknowledged data packet but not yet acknowledged as received; and

retransmitting the presumed lost data packets.

11. The method of claim 9, further comprising:

a step for determining whether transmitted data packets should be retransmitted; and

retransmitting data packets responsive to the step for determining.

12. The method of claim 9, wherein the transmitted and retransmitted data packets include an identifier, and wherein the received acknowledgements include identifying information that comprises a function of the identifier.

13. The method of claim 12, wherein the identifying information includes the identifier.

14. The method of claim 12, wherein the identifier is a time stamp.

15. The method of claim 12, wherein the data packets conform to the TCP/IP protocol, and the identifying information is included in an IP ID field of each data packet.

16. The method of claim 15, wherein the identifying information in the acknowledgement packet comprises the identifier in an IP ID field of the acknowledgement packet with a most significant bit reversed.

17. A computer program product for communicating with a remote system using Internet Protocol (IP) via a computer network, the computer program product comprising a computer-readable medium containing computer program code for performing the operations:

transmitting a data packet to the remote system;

retransmitting the data packet to the remote system;

receiving an acknowledgement packet indicating that the data packet was received by the remote system, the acknowledgement packet identifying the data packet; and

associating the acknowledgement packet with either the transmission or the retransmission of the data packet, based on identifying information in the acknowledgement packet, thereby determining whether the transmission or the retransmission of the data packet was received and acknowledged by the remote system.

18. The computer program product of claim 17, the computer program code further for performing the operations:

presuming lost any data packets that (1) have not been acknowledged and (2) were transmitted before the acknowledged transmission or retransmission of the data packet; and

retransmitting the presumed lost data packets.

19. The computer program product of claim 17, wherein each instance of the transmission and the retransmission of the data packet includes a unique identifier, and the identifying information in the acknowledgement packet is a function of the identifier.

20. The computer program product of claim 19, wherein the identifying information includes the identifier.

21. The computer program product of claim 19, wherein the identifier is a time stamp.

22. The computer program product of claim 19, wherein the data packet conforms to the TCP/IP protocol, and the identifying information is included in an IP ID field of the data packet.

23. The computer program product of claim 22, wherein the identifying information in the acknowledgement packet comprises the identifier in an IP ID field of the acknowledgement packet with a most significant bit reversed.

24. The computer program product of claim 17, wherein the associating is performed in a flow control module coupled to the sender.

27. The computer program product of claim 17, the computer program code further for performing the operations:

a step for determining whether transmitted data packets should be retransmitted; and

retransmitting data packets responsive to the step for determining.

28. The computer program product of claim 17, wherein the transmitted and retransmitted data packets include an identifier, and wherein the received acknowledgements include identifying information that comprises a function of the identifier.

29. The computer program product of claim 28, wherein the identifying information includes the identifier.

30. The computer program product of claim 28, wherein the identifier is a time stamp.

31. The computer program product of claim 28, wherein the data packets conform to the TCP/IP protocol, and the identifying information is included in an IP ID field of each data packet.

32. The computer program product of claim 31, wherein the identifying information in the acknowledgement packet comprises the identifier in an IP ID field of the acknowledgement packet with a most significant bit reversed.

25. A computer program product for transmitting data packets to a receiver over a network, the computer program product comprising a computer-readable medium containing computer program code for performing the operations:

transmitting a plurality of data packets to the receiver;

retransmitting a number of the transmitted data packets responsive to an indication that the retransmitted data packets were not received by the receiver;

maintaining a unique transmit number for each instance of a transmitted or retransmitted data packet;

receiving acknowledgements indicating that at least some of the data packets have been received; and

a step for disambiguating the received acknowledgements to determine for each ambiguous acknowledgement the instance of transmitted or retransmitted data packet to which the ambiguous acknowledgement relates.

26. The computer program product of claim 25, the computer program code further for performing the operations:

for each received acknowledgment, presuming lost any data packets that were transmitted before the acknowledged data packet but not yet acknowledged as received; and

retransmitting the presumed lost data packets.