TCP throughput control by imposing temporal delay

• US 8,681,610 B1
• Filed: 01/30/2013
• Issued: 03/25/2014
• Est. Priority Date: 02/01/2007
• Status: Active Grant

• Current Assignee: F5 Networks, Inc. (F5 Incorporated)
• Original Assignee: F5 Networks, Inc. (F5 Incorporated)
• Inventors: Mukerji, Arindum
• Primary Examiner(s): Rinehart, Mark
• Assistant Examiner(s): Onamuti, Gbemileke
• Application Number:
  US13/754,735
• Time in Patent Office: 419 Days
• Field of Search: 370/229
• US Class Current: 370/229
• CPC Class Codes: H04L 47/26 using explicit feedback to the source, e.g. choke packets
• CPC Class Codes: H04L 47/265 sent by intermediate network nodes
• CPC Class Codes: H04L 47/267 sent by the destination endpoint network streaming of media packets with control of the source by the destination H04L65/613
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 47/323 Discarding or blocking control packets, e.g. ACK packets
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures

Abstract

A system, apparatus, and method are directed towards managing traffic over a network by imposing temporal delays in acknowledgments (ACKs). A Traffic Management Device (TMD), interposed between two network session end-points monitors a buffer of relayed packets. If the contents of the buffer exceed a threshold value, delays are imposed on sending of acknowledgements. If the buffer contents exceed the threshold, and the buffer'"'"'s contents are increasing, the delays may be increased. If the buffer'"'"'s contents are about at steady state, the acknowledgement delays may be decreased, or maintained at a current delay status. In one embodiment, if the sender is sending packets at a rate above a receiver'"'"'s ability to receive the packets, and the sender appears not to be decreasing its rate of transmission, an explicit congestion notification echo (ECE) may be sent to the sender.

Claims

1. A network device for managing a communications between devices, comprising:

a buffer for use in receiving and storing packets; and

one or more physical devices operative to perform actions comprising;

receiving a packet from a sending device;

when it is determined that contents of the buffer are above a threshold value and

also that the contents of the buffer are increasing, then selectively increasing a delay in sending of an acknowledgement (ACK) to the sending device;

when it is determined that both the contents of the buffer are above the threshold value and the contents of the buffer is decreasing, then selectively decreasing the delay of sending the ACK to the sending device; and

when it is determined that the contents of the buffer are substantially increasing above the threshold value and a round trip time for the sending device is less than a round trip time for a destination device, selectively sending an explicit congestion notification echo (ECE) to the sending device.

2. The network device of claim 1, wherein the one or more physical devices operative to perform actions comprising:

when it is determined that the contents of the buffer are substantially increasing above the threshold value and the ACK delays are equal to or greater than a retransmission timeout (RTO) threshold value, then sending and ECE to the sending device.

3. The network device of claim 1, wherein the one or more physical devices operative to perform actions comprising:

when it is determined that the contents of the buffer are substantially increasing above the threshold value and the sending device is sending packets at a rate that is higher than a rate that the destination device is advertising as its ability to receive packets, then sending an ECE to the sending device.

4. The network device of claim 1, wherein selectively decreasing or increasing the delay of sending the ACK further comprises one of adjusting a temporal delay based on a relationship between a round trip time for packets for the sending device and a round trip time for packets for the destination device.

5. The network device of claim 1, wherein selectively decreasing or increasing sending of an ACK further comprises selectively modifying temporal delays associated with ACKs not included within a packet that also includes a data payload.

6. The network device of claim 1, wherein selectively increasing or decreasing sending of an ACK further comprises employing one of stepping a modification of a temporal delay for sending the ACK, or ramping the modification of the temporal delay for sending the ACK.

7. The network device of claim 1, wherein the one or more physical devices operative to perform actions further comprising:

when it is determined that the buffer is substantially full based on a second threshold, dropping the received packet.

8. A processor-based method operating on a network device, comprising:

receiving a packet from a sending device at the network device, the packet being intended for a destination device;

when it is determined that contents of a buffer are above a threshold value and also that the contents of the buffer are increasing, then selectively increasing a delay in sending of an acknowledgement (ACK) to the sending device;

when it is determined that both the contents of the buffer are above the threshold value and the contents of the butler is decreasing, then selectively decreasing the delay of sending the ACK to the sending device; and

when it is determined that the contents of the buffer are substantially increasing above the threshold value and a round trip time for the sending device is less than a round trip time for the destination device, selectively using a Domain Specific Access Control Restriction (DSACR) to control a round trip time of the sending device.

9. The processor-based method of claim 8, further comprising:

when it is determined that the contents of the buffer are substantially increasing above the threshold value and the ACK delays are equal to or greater than a retransmission timeout (RTO) threshold value, then sending an explicit congestion notification echo (ECE) to the sending device.

10. The processor-based method of claim 8, further comprising:

when it is determined that the contents of the buffer are substantially increasing above the threshold value and the sending device is sending packets at a rate that is higher than a rate that the destination device is advertising as its ability to receive packets, then sending an explicit congestion notification echo (ECE) to the sending device.

11. The processor-based method of claim 8, wherein selectively decreasing or increasing the delay of sending the ACK further comprises one of adjusting a temporal delay based on a relationship between a round trip time for packets for the sending device and a round trip time for packets for the destination device.

12. The processor-based method of claim 8, wherein selectively decreasing or increasing sending of an ACK further comprises selectively modifying temporal delays associated with ACKs not included within a packet that also includes a data payload.

13. The processor-based method of claim 8, wherein selectively increasing or decreasing sending of an ACK further comprises employing one of stepping a modification of a temporal delay for sending the ACK, or ramping the modification of the temporal delay for sending the ACK.

14. An apparatus comprising a non-transitory computer readable medium, having computer-executable instructions stored thereon, that in response to execution by a computing device interposed between a sending device and a destination device enables the interposed computing device to perform actions, comprising:

receiving a packet from the sending device;

when it is determined that contents of a buffer are above a threshold value and also that the contents of the buffer are increasing, then selectively increasing a delay in sending of an acknowledgement (ACK) to the sending device;

when it is determined that both the contents of the buffer are above the threshold value and the contents of the buffer is decreasing, then selectively decreasing the delay of sending the ACK to the sending device; and

when it is determined that the contents of the buffer are substantially increasing above the threshold value and a round trip time for the sending device is less than a round trip time for the destination device, selectively sending an explicit congestion notification echo (ECE) to the sending device.

15. The apparatus of claim 14, wherein the computing device performs actions, further including:

when it is determined that the contents of the buffer are substantially increasing above the threshold value and the ACK delays are equal to or greater than a retransmission timeout (RTO) threshold value, then sending an ECE to the sending device.

16. The apparatus of claim 14, wherein the computing device performs actions, further including:

when it is determined that the contents of the buffer are substantially increasing above the threshold value and the sending device is sending packets at a rate that is higher than a rate that the destination device is advertising as its ability to receive packets, then sending an ECE to the sending device.

17. The apparatus of claim 14, wherein selectively decreasing or increasing the delay of sending the ACK further comprises one of adjusting a temporal delay based on a relationship between a round trip time for packets for the sending device and a round trip time for packets for the destination device.

18. The apparatus of claim 14, wherein selectively decreasing or increasing the sending of an ACK further comprises selectively modifying temporal delays associated with the ACKs not included within a packet that also includes a data payload.

19. The apparatus of claim 14, wherein selectively increasing or decreasing sending of an ACK further comprises employing one of stepping a modification of a temporal delay for sending the ACK, or ramping the modification of the temporal delay for sending the ACK.