Data transport acceleration and management within a network communication system

• US 7,099,273 B2
• Filed: 01/29/2002
• Issued: 08/29/2006
• Est. Priority Date: 04/12/2001
• Status: Active Grant

• Current Assignee: OptiMorphix, Inc.
• Original Assignee: Bytemobile Inc. (Cloud Software Group)
• Inventors: Ha, Sungwon, Bharghavan, Vaduvur, Ramchandran, Kannan, Madhow, Upamanyu, Kim, Tae-eun, Han, Sung-wook
• Primary Examiner(s): Patel, Ajit
• Application Number:
  US10/061,574
• Publication Number:
  US 20020150048A1
• Time in Patent Office: 1,673 Days
• Field of Search: 370/229, 370/230, 370/230.1, 370/231, 370/232, 370/235, 370/235.1, 370/236, 370/252, 709/235
• US Class Current: 370/229
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0018 based on latency requirement
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/1874 Buffer management
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• 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 47/20 Traffic policing
• CPC Class Codes: H04L 47/28 in relation to timing considerations
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 47/37 Slow start
• CPC Class Codes: H04L 47/43 Assembling or disassembling of packets, e.g. segmentation and reassembly [SAR]
• 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 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/162 involving adaptations of sockets based mechanisms secure socket layer H04L63/168
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

Improved data transport and management within a network communication system may be achieved by utilizing a transmit timer incorporated within the sender device and exploiting host-level statistics for a plurality of connections between a sender and receiver. The period of the transmit timer may be periodically adjusted based on a ratio of the smoothed round-trip time and the smoothed congestion window, thereby reducing or eliminating bursty data transmission commonly associated with conventional TCP architectures. For applications having a plurality of connections between a sender and a receiver that share a common channel, such as web applications, the congestion window and smoothed round trip time estimates for all active connections may be used to initialize new connections and allocate bandwidth among existing connections. This aspect of the present invention may reduce the destructive interference that may occur as different connections compete with one another to maximize the bandwidth of each connection without regard to other connections serving the same application. Error recovery may also be improved by incorporating a short timer and a long timer that are configured to reduce the size of the congestion window and the corresponding transmission rate in response to a second packet loss with a predefined time period in order to increase resilience to random packet loss.

Claims

1. A method of transferring data from a sender to a receiver in a communication network, the method comprising:

establishing a connection between the sender and the receiver;

measuring round trip times of data packets sent from the sender to the receiver;

determining a congestion window parameter that specifies a maximum number of unacknowledged data packets that may be sent to the receiver; and

transmitting additional data packets to the receiver in response to expiration of a transmit timer, the period of the transmit timer based on the round trip time measurements and the congestion window parameter.

2. The method of claim 1, wherein the step of measuring the round trip times comprises measuring the time between transmission of a data packet and receipt of a corresponding acknowledgement.

3. The method of claim 1, wherein the step of determining comprises adjusting the congestion window parameter in response to receipt of acknowledgements from the receiver.

4. The method of claim 3, wherein the step of adjusting comprises incrementing the congestion window parameter in response to receipt of each acknowledgement.

5. The method of claim 3, wherein the step of adjusting comprises incrementing the congestion window parameter in response to receipt of a number of acknowledgments equal to the size of the then-current congestion window parameter.

6. The method of claim 3, wherein the step of adjusting comprising increasing the congestion window parameter by an amount equal to a number of buffers effectively freed by each acknowledgement.

7. The method of claim 1, wherein the period of the timer is based on a smoothed round trip time and a smoothed congestion window.

8. The method of claim 7, wherein the period of the timer is based on a ratio of the smoothed round trip time and the smoothed congestion window.

9. The method of claim 7, wherein the smoothed round trip time is based on an average and mean deviation of a plurality of round trip time measurements.

10. The method of claim 7, wherein the smooth round trip time is based on a weighted sum of a previous smoothed round trip time and a then-current round trip time measurement.

11. The method of claim 7, wherein the smoothed congestion window comprises a weighted sum of a previous smoothed congestion window and a then-current congestion window parameter.

12. The method of claim 1, wherein the step of transmitting comprises multiplexing new and retransmitted data packets.

13. The method of claim 12, wherein the step of multiplexing comprises determining whether to transmit either the new or the retransmitted data packets based on expiration of a timer.

14. The method of claim 12, wherein the step of multiplexing comprises determining whether to transmit either the new or the retransmitted data packets based on a number of duplicate acknowledgments exceeding a predetermined threshold.

15. A system for transferring data from a sender to a receiver in a communication network, the system comprising:

a processor; and

a memory unit operably coupled to the processor, the memory unit storing instructions which when executed by the processor cause the processor to operate so as to;

establish a connection between the sender and the receiver;

measure round trip times of data packets sent from the sender to the receiver;

determine a congestion window parameter that specifies a maximum number of unacknowledged data packets that may be sent to the receiver; and

transmit additional data packets to the receiver in response to expiration of a transmit timer, the period of the transmit timer based on the round trip time measurements and the congestion window parameter.