Wavefront detection and disambiguation of acknowledgements

• US 8,259,729 B2
• Filed: 09/25/2009
• Issued: 09/04/2012
• Est. Priority Date: 10/30/2002
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Samuels, Allen R., Sutter, Paul G.
• Primary Examiner(s): Weidner, Timothy J
• Application Number:
  US12/567,402
• Publication Number:
  US 20100046372A1
• Time in Patent Office: 1,075 Days
• Field of Search: None
• US Class Current: 370/394
• 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 using Internet Protocol (IP) via a computer network, the method comprising:

transmitting, by a flow control module configured on a device, a data packet from a sender to a remote system, the transmitted data packet including a transport layer sequence number and a first internet layer internet protocol identifier (IP ID) field, the first IP ID field comprising a first unique value;

retransmitting, by the flow control module, the data packet to the remote system, the retransmitted data packet including the transport layer sequence number and a second IP ID field, the second IP ID field comprising a second unique value different than the first unique value;

receiving, by the flow control module, an acknowledgment packet sent by the remote system, the acknowledgement packet including the transport layer sequence number and a third IP ID field, the third IP ID field comprising a third value set to one of a function of the first unique value or a function of the second unique value; and

determining, by the flow control module, whether the received acknowledgment packet acknowledges receipt by the remote system of the transmission of the data packet or the retransmission of the data packet, via the value of the third IP ID field.

2. The method of claim 1, wherein receiving an acknowledgment packet sent by the remote system further comprises receiving the acknowledgment packet including the third IP ID field, the third IP ID field comprising the third value set to one of the first unique value with a predetermined bit reversed or the second unique value with a predetermined bit reversed.

3. The method of claim 2, wherein the predetermined bit reversed is a most significant bit of the third IP ID field.

4. The method of claim 1, wherein the first unique value and second unique value comprise timestamps.

5. The method of claim 1, wherein the first unique value and second unique value comprise unique counter values.

6. The method of claim 1, wherein the first unique value and second unique value are sequential.

7. The method of claim 1, further comprising:

transmitting, by the flow control module, one or more additional data packets from the sender to the remote system prior to retransmitting the data packet; and

presuming lost, by the flow control module, the one or more additional data packets sent prior to retransmitting the data packet, responsive to;

(i) determining that the received acknowledgement packet acknowledges receipt by the remote system of the retransmission of the data packet, and (ii) receipt of the one or more additional data packets not being acknowledged by the remote system.

8. A system for communicating using Internet Protocol (IP) via a computer network, the system comprising:

a device deployed between a sender and a remote system, the device comprising a flow control module, the flow control module configured for;

transmitting a data packet from the sender to the remote system, the transmitted data packet including a transport layer sequence number and a first internet layer internet protocol identifier (IP ID) field, the first IP ID field comprising a first unique value;

retransmitting the data packet to the remote system, the retransmitted data packet including the transport layer sequence number and a second IP ID field, the second IP ID field comprising a second unique value different than the first unique value;

receiving an acknowledgment packet sent by the remote system, the acknowledgement packet including the transport layer sequence number and a third IP ID field, the third IP ID field comprising a third value set to one of a function of the first unique value or a function of the second unique value; and

determining whether the received acknowledgment packet acknowledges receipt by the remote system of the transmission of the data packet or the retransmission of the data packet, via the value of the third IP ID field.

9. The system of claim 8, wherein the flow control module is further configured for receiving the acknowledgment packet including the third IP ID field, the third IP ID field comprising the third value set to one of the first unique value with a predetermined bit reversed or the second unique value with a predetermined bit reversed.

10. The system of claim 9, wherein the predetermined bit reversed is a most significant bit of the third IP ID field.

11. The system of claim 8, wherein the first unique value and second unique value comprise timestamps.

12. The system of claim 8, wherein the first unique value and second unique value comprise unique counter values.

13. The system of claim 8, wherein the first unique value and second unique value are sequential.

14. The system of claim 8, wherein the flow control module is further configured for:

transmitting one or more additional data packets from the sender to the remote system prior to retransmitting the data packet; and

presuming lost the one or more additional data packets sent prior to retransmitting the data packet, responsive to;

(i) determining that the received acknowledgement packet acknowledges receipt by the remote system of the retransmission of the data packet, and (ii) receipt of the one or more additional data packets not being acknowledged by the remote system.