Granted Patent B2

US 10,536,382 · App. 15/969,613 · Granted Jan 14, 2020

Abstract

Claims (68)

1. A system for controlling data flow across a computer network comprising a first performance enhancing proxy device (PEP 1 ) on a client-facing segment of the network and a second performance enhancing proxy device (PEP 2 ) on a server-facing segment of the network, the system comprising:

the PEP 2 , the PEP 2 including:

a receiver for receiving flow control information from across a control channel between the PEP 1 and the PEP 2 , the flow control information including round-trip packet latency measurement (Li) on the client-facing segment and transmit buffer congestion window information of the PEP 1 , wherein the flow control information is for each TCP connection on the client-facing segment;

a determiner for determining whether each TCP connection of the client-facing segment has a congested TCP packet flow; and

a congestion reliever for relieving the congestion of each TCP connection of the client-facing segment having a congested TCP packet flow, the congestion reliever comprising:

a synchronizer for synchronizing a receive buffer receive window size of the PEP 2 to be the same as a transmit buffer congestion window size of the PEP 1 ; and

a delayer for:

determining whether Li is less than the preset threshold level Tlim, or whether Li is greater than or equal to the preset threshold level Tlim; and

delaying acknowledgments (ACKs) received by the PEP 2 from the PEP 1 by a time Tack, wherein Tack a) is based on Li when Li is less than the preset threshold level Tlim, or b) is based on a preset threshold level (Tlim) when Li is greater than or equal to the preset threshold level Tlim.

2. The system of claim 1 , wherein the delayer delaying the ACKs comprises:

setting Tack to ½ Li when Li is less than the preset threshold level Tlim; and

setting Tack to ½ Tlim when Li is greater than or equal to the preset threshold level Tlim.

3. The system of claim 1 , wherein the synchronizer synchronizing comprises:

setting the receive buffer receive window size of the PEP 2 to be whichever is smaller of the transmit buffer congestion window size of the PEP 1 and the receive buffer receive window size of the PEP 2 .

4. The system of claim 1 , wherein the determiner determining comprises determining based at least on the transmit buffer congestion window information; and

wherein the transmit buffer congestion window information comprises at least one of an explicit congestion notification (ECN) received by the receiver for each TCP connection on the client-facing segment or the transmit buffer congestion window size.

5. The system of claim 1 , the PEP 2 further comprising:

a measurer for measuring a round-trip packet latency Lr on the server-facing segment of the computer network; and

a throughput setter for setting the throughput of the server facing segment of the PEP 2 to be a function of the receive buffer receive window size of the PEP 2 and whichever is smaller of the Li and Lr.

6. The system of claim 1 , the PEP 1 comprising:

an identifier for identifying each TCP connection;

a measurer for measuring the round-trip packet latency measurement Li;

determiner for determining the transmit buffer congestion window information; and

a transmitter for transmitting the Li and the transmit buffer congestion window information for the TCP connection across the control channel to the PEP 2 .

7. A non-transitory machine-readable storage medium storing a program having instructions which when executed by a processor will cause the processor to:

receive flow control information from across a control channel between the PEP 1 and the PEP 2 , the flow control information including round-trip packet latency measurement (Li) on the client-facing segment and transmit buffer congestion window information of the PEP 1 , wherein the flow control information is for each TCP connection on the client-facing segment;

determine whether each TCP connection of the client-facing segment has a congested TCP packet flow; and

for each TCP connection of the client-facing segment having a congested TCP packet flow:

synchronize a receive buffer receive window size of the PEP 2 to be the same as a transmit buffer congestion window size of the PEP 1 ;

determine whether Li is less than the preset threshold level Tlim, or whether Li is greater than or equal to the preset threshold level Tlim; and

delay acknowledgments (ACKs) received by the PEP 2 from the PEP 1 by a time Tack, wherein Tack a) is based on Li when Li is less than the preset threshold level Tlim, or b) is based on a preset threshold level (Tlim) when Li is greater than or equal to the preset threshold level Tlim.

8. The non-transitory machine-readable storage medium of claim 7 , wherein delaying ACKs comprises:

setting Tack to ½ Li when Li is less than a preset threshold level Tlim; and

setting Tack to ½ Tlim when Li is greater than or equal to the preset threshold level Tlim.

9. The non-transitory machine-readable storage medium of claim 7 , wherein synchronizing comprises:

setting the receive buffer receive window size of the PEP 2 to be whichever is smaller of the transmit buffer congestion window size of the PEP 1 and the receive buffer receive window size of the PEP 2 .

10. The non-transitory machine-readable storage medium of claim 7 , wherein determining comprises determining based at least on the transmit buffer congestion window information; and

wherein the transmit buffer congestion window information comprises at least one of an explicit congestion notification (ECN) received by the receiver for each TCP connection on the client-facing segment or the transmit buffer congestion window size.

11. The non-transitory machine-readable storage medium of claim 7 , wherein the program having instructions which when executed by a processor will further cause the processor to:

determine a round-trip packet latency Lr on the server-facing segment of the computer network; and

set the throughput of the server facing segment of the PEP 2 to be a function of the receive buffer receive window size of the PEP 2 and whichever is smaller of the Li and Lr.

12. The non-transitory machine-readable storage medium of claim 7 , wherein the program having instructions which when executed by a processor will further cause the processor to:

identify each TCP connection;

determine the round-trip packet latency measurement Li;

determine the transmit buffer congestion window information; and

transmit the Li and the transmit buffer congestion window information for the TCP connection across the control channel to the PEP 2 .

13. A data flow control process across a computer network comprising a first performance enhancing proxy device (PEP 1 ) on a client-facing segment of the network and a second performance enhancing proxy device (PEP 2 ) on a server-facing segment of the network, the flow control process comprising:

receiving flow control information from across a control channel between the PEP 1 and the PEP 2 , the flow control information including round-trip packet latency measurement (Li) on the client-facing segment and transmit buffer congestion window information of the PEP 1 , wherein the flow control information is for each TCP connection on the client-facing segment;

determining whether each TCP connection of the client-facing segment has a congested TCP packet flow; and

for each TCP connection of the client-facing segment having a congested TCP packet flow:

synchronizing a receive buffer receive window size of the PEP 2 to be the same as a transmit buffer congestion window size of the PEP 1 ;

determining whether Li is less than the preset threshold level Tlim, or whether Li is greater than or equal to the preset threshold level Tlim; and

delaying acknowledgments (ACKs) received by the PEP 2 from the PEP 1 by a time Tack, wherein Tack a) is based on Li when Li is less than the preset threshold level Tlim, or b) is based on a preset threshold level (Tlim) when Li is greater than or equal to the preset threshold level Tlim.

14. The flow control process of claim 13 , wherein delaying ACKs comprises:

setting Tack to ½ Li when Li is less than a preset threshold level Tlim; and

setting Tack to ½ Tlim when Li is greater than or equal to the preset threshold level Tlim.

15. The flow control process of claim 13 , wherein synchronizing comprises:

setting the receive buffer receive window size of the PEP 2 to be whichever is smaller of the transmit buffer congestion window size of the PEP 1 and the receive buffer receive window size of the PEP 2 .

16. The flow control process of claim 13 , wherein determining whether each TCP connection of the client-facing segment has a congested TCP packet flow is based at least on the transmit buffer congestion window information; and

wherein the transmit buffer congestion window information comprises at least one of an explicit congestion notification (ECN) received by the receiver for each TCP connection on the client-facing segment or the transmit buffer congestion window size.

17. The flow control process of claim 13 , further comprising:

determining a round-trip packet latency Lr on the server-facing segment of the computer network; and

setting the throughput of the server facing segment of the PEP 2 to be a function of the receive buffer receive window size of the PEP 2 and whichever is smaller of the Li and Lr.

18. The flow control process of claim 13 , further comprising:

identifying each TCP connection;

determining the round-trip packet latency measurement Li;

determining the transmit buffer congestion window information; and

transmitting the Li and the transmit buffer congestion window information for the TCP connection across the control channel to the PEP 2 .

Assignments (13)