SYSTEMS AND METHODS OF USING PACKET BOUNDARIES FOR REDUCTION IN TIMEOUT PREVENTION

• US 20070206621A1
• Filed: 03/12/2007
• Published: 09/06/2007
• Est. Priority Date: 07/29/2003
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Samuels, Allen, Plamondon, Robert, Ovsiannikov, Michael
• Granted Patent: US 8,270,423 B2
• Time in Patent Office: Days
• US Class Current: 370/413
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 1/189 Transmission or retransmission of more than one copy of a message
• CPC Class Codes: H04L 12/28 characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks] wireless communication networks H04W ; arrangements for dividing the transmission path H04W40/00
• CPC Class Codes: H04L 12/56 Packet switching systems
• CPC Class Codes: H04L 2001/0092 Error control systems characterised by the topology of the transmission link
• 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 43/0829 Packet loss
• CPC Class Codes: H04L 47/40 using split connections
• 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

Systems and methods for utilizing transaction boundary detection methods in queuing and retransmission decisions relating to network traffic are described. By detecting transaction boundaries and sizes, a client, server, or intermediary device may prioritize based on transaction sizes in queuing decisions, giving precedence to smaller transactions which may represent interactive and/or latency-sensitive traffic. Further, after detecting a transaction boundary, a device may retransmit one or more additional packets prompting acknowledgements, in order to ensure timely notification if the last packet of the transaction has been dropped. Systems and methods for potentially improving network latency, including retransmitting a dropped packet twice or more in order to avoid incurring additional delays due to a retransmitted packet being lost are also described.

Claims

1. A method for reducing transmission timeouts by selectively transmitting additional packets from an intermediary device based on identifying transaction boundaries, the method comprising:

(a) receiving, by a device via a connection between a sender and a receiver, a first packet from the sender via the connection;

(b) transmitting, by the device, the first packet to the receiver;

(c) determining, by the device, that the first packet is the last packet of a transaction;

(d) generating, by the device in response to the determination, at least one additional packet; and

(e) transmitting, by the device after the first packet has been transmitted to the receiver, the at least one additional packet to the receiver via the connection.

2. The method of claim 1, wherein the connection comprises a transport layer connection.

3. The method of claim 1, wherein the device is one of a client, a server, or a network appliance.

4. The method of claim 1, wherein step (c) comprises determining, by the device, that the first packet is smaller than a maximum packet size of the connection.

5. The method of claim 1, wherein step (c) comprises determining, by the device, that the first packet is smaller than a maximum packet size of connection and was immediately preceded by at least one packet of the maximum packet size.

6. The method of claim 1, wherein step (c) comprises determining, by the device, that the a buffer corresponding to the connection has transitioned from non-empty to empty.

7. The method of claim 1, wherein step (d) comprises generating, by the device in response to the determination, at least one additional packet, wherein the at least one additional data packet comprises an indication for the receiver to transmit at least one acknowledgement.

8. The method of claim 1, wherein step (d) comprises generating, by the device in response to the determination, at least one additional packet, wherein the at least one additional data packet comprises the first data packet.

9. The method of claim 1, wherein step (d) comprises generating, by the device in response to the determination, at least one additional packet, wherein the at least one additional data packet comprises a portion of the received data packet.

10. The method of claim 1, wherein step (d) comprises generating, by the device in response to the determination, at least one additional packet, wherein the at least one additional data packet is generated according to a forward error correction technique for previously transmitted data.

11. The method of claim 1, wherein step (d) comprises generating, by the device in response to the determination, at least one additional packet, wherein the number of additional data packets transmitted is selected based on a current loss rate for the transport layer connection.

12. The method of claim 1, further comprising the steps of:

(f) receiving, by the device, at least one acknowledgement corresponding to the at least one additional data packet;

(g) determining, by the device, based on the received at least one acknowledgement, that one or more previously transmitted data packets have not been received; and

(h) retransmitting, by the device, the one or more previously transmitted data packets that have not been received.

13. A device for reducing transmission timeouts by selectively transmitting additional packets from an intermediary device based on identifying transaction boundaries, the device comprising:

a packet processor which receives a first packet from a sender via a connection; and

transmits the first packet to a receiver;

a flow controller which determines that the first packet is the last packet of a transaction;

generates, in response to the determination, at least one additional packet; and

transmits, after the first packet has been transmitted to the receiver, the at least one additional packet to the receiver.

14. The system of claim 13, wherein the device serves as an intermediary for a transport layer connection between the sender and the receiver.

15. The system of claim 13, wherein the device is one of a client, a server, or a network appliance.

16. The system of claim 13, wherein the device comprises a transparent proxy.

17. The system of claim 13, wherein the flow controller determines that a buffer corresponding to the connection has transitioned from non-empty to empty.

18. The system of claim 13, wherein the flow controller determines that the first packet is smaller than a maximum packet size of the transport layer connection.

19. The system of claim 13, wherein the flow controller determines that the first packet is smaller than a maximum packet size of the transport layer connection and was immediately preceded by at least one packet of the maximum packet size.

20. The system of claim 13, wherein the flow controller generates, in response to the determination, at least one additional packet, wherein the at least one additional data packet comprises an indication for the receiver to transmit at least one acknowledgement.

21. The system of claim 13, wherein the flow controller generates, in response to the determination, at least one additional packet, wherein the at least one additional data packet comprises the first data packet.

22. The system of claim 13, wherein the flow controller generates, in response to the determination, at least one additional packet, wherein the at least one additional data packet comprises a portion of the received data packet.

23. The system of claim 13, wherein the flow controller generates, in response to the determination, at least one additional packet, wherein the at least one additional data packet is generated according to a forward error correction technique for previously transmitted data.

24. The system of claim 13, wherein the flow controller generates, in response to the determination, at least one additional packet, wherein the number of additional data packets transmitted is selected based on a current loss rate for the transport layer connection.

25. The system of claim 13, wherein the packet processor receives at least one acknowledgement corresponding to the at least one additional data packet;

determines, based on the received at least one acknowledgement, that one or more previously transmitted data packets have not been received; and

retransmits the one or more previously transmitted data packets that have not been received.

26. A system for reducing transmission timeouts by selectively transmitting additional packets from an intermediary device based on identifying transaction boundaries, the system comprising:

means for receiving, by a device via a connection between a sender and a receiver, a first packet from the sender via the connection;

means for transmitting, by the device, the first packet to the receiver;

means for determining, by the device, that the first packet is the last packet of a transaction;

means for generating, by the device in response to the determination, at least one additional packet; and

means for transmitting, by the device after the first packet has been transmitted to the receiver, the at least one additional packet to the receiver via the connection.