METHODS TO IMPROVE TRANSMISSION CONTROL PROTOCOL (TCP) PERFORMANCE OVER LARGE BANDWIDTH LONG DELAY LINKS

• US 20090046717A1
• Filed: 08/15/2007
• Published: 02/19/2009
• Est. Priority Date: 08/15/2007
• Status: Active Grant

• Current Assignee: CA, Inc. (d/b/a CA Technologies) (Broadcom, Inc.)
• Original Assignee: Blue Coat Systems Incorporated (Gen Digital Inc.)
• Inventors: Li, Qing
• Granted Patent: US 8,004,983 B2
• Time in Patent Office: Days
• US Class Current: 370/392
• 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 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/166 IP fragmentation; TCP segmentation

Abstract

TCP options are provided to address TCP performance problems during data exchanges over large bandwidth long delay communication links. These options address problems such as in sequence tail drops, inaccurate estimations of available bandwidth over a communication link, and slow responses to dynamic changes in link conditions.

Claims

1. A method, comprising transmitting a Transmission Control Protocol (TCP) segment from a sender to a receiver, the TCP segment including a TCP header with an option field coded so as to indicate that additional TCP segments are being so transmitted.

2. The method of claim 1, wherein the option field is coded with an option cue having a kind field, a length field and a field indicating that the additional TCP segments are being so transmitted.

3. The method of claim 2, wherein the kind field is coded so as to be indicative of a TCP option used to indicate that the additional TCP segments are being so transmitted.

4. A method, comprising transmitting a Transmission Control Protocol (TCP) segment, the TCP segment including a TCP header with an option field coded so as to advise a recipient of the TCP segment of a path bandwidth as perceived by a sender of the TCP segment.

5. The method of claim 4, wherein the option field is coded with a kind field, a length field and a field indicating an estimate of the path bandwidth as perceived by the sender.

6. A method comprising transmitting a TCP segment with a TCP option included in a header of the TCP segment, the option coded so as to indicate to a receiver of the TCP segment that a sender of the TCP segment is capable of generating TCP segments coded so as to indicate that additional TCP segments are being transmitted.

7. A method comprising transmitting a TCP segment with a TCP option included in a header of the TCP segment, the option coded so as to indicate to a recipient of the TCP segment that a sender of the TCP segment is capable of transmitting TCP segments coded so as to advise the recipient thereof of a path bandwidth as perceived by the sender.

8. A Transmission Control Protocol (TCP) option comprising one or more fields configured to advise a recipient of a TCP segment including the TCP option that additional TCP packets are being transmitted by a sender of the TCP segment including the TCP option.

9. A Transmission Control Protocol (TCP) option comprising one or more fields configured to advise a recipient of a TCP segment including the TCP option of a path bandwidth as perceived by a sender of the TCP segment.

10. A Transmission Control Protocol (TCP) option comprising one or more fields configured to indicate that a sender of a TCP segment including the TCP option is capable of transmitting additional TCP segments with TCP options coded to advise a recipient thereof that additional TCP packets are being transmitted by the sender.

11. A Transmission Control Protocol (TCP) option comprising one or more fields configured to indicate that a sender of a TCP segment including the TCP option is capable of transmitting additional TCP segments with TCP options coded so as to advise a recipient thereof of a path bandwidth as perceived by the sender.

12. A method, comprising receiving a first Transmission Control Protocol (TCP) segment including a TCP header with an option field coded so as to indicate that additional TCP segments are being transmitted, detecting a TCP in sequence tail-drop condition, and requesting retransmission of a second TCP segment prior to expiry of a full TCP retransmission timeout period when at least one of the additional TCP segments are not received within a predetermined time period.

13. The method of claim 13, wherein the predetermined time period comprises a multiple of a dynamically computed inter-segment delay time according to current path conditions.

14. A method, comprising minimizing packet loss across a communication link by setting a Transmission Control Protocol (TCP) segment transmission rate according to an estimate of path bandwidth, which estimate is computed dynamically according to predefined algorithms using a combined path bandwidth provided by a receiver of the packets in a TCP option of a TCP header, with the path bandwidth estimated by the sender of the TCP packets.

15. A method, comprising maximizing path bandwidth utilization across a communication link by setting a Transmission Control Protocol (TCP) segment transmission rate according to an estimate of path bandwidth, which estimate is computed dynamically according to predefined algorithms using a combined path bandwidth provided by a receiver of the packets in a TCP option of a TCP header, with the path bandwidth estimated by the sender of the TCP packets.