TCP performance predictor
Technology is disclosed herein for monitoring a network path. In an implementation, a device on a network path obtains a burst capacity of the network path, determines a round trip time associated with a burst of traffic sent over the network path, and determines a predicted throughput of the network path based at least in part on the burst capacity of the network path and the round trip time of the burst of traffic.
1. A method for predicting a throughput of a Transmission Control Protocol (TCP) path between a sender and a receiver over a network path, the method comprising: transmitting, by a first TCP predictor on a first device, a number of test packets over the network path;
receiving, by a second TCP predictor on a second device, said number of test packets and sending reply packets to the first TCP predictor on said first device, said reply packets including a timestamp;
determining, by said first TCP predictor on said first device, a round trip time and a burst capacity of the network path based on said reply packets; and
predicting, by said first TCP predictor on said first device, the throughput of said network path based on said burst capacity divided by said roundtrip time of said network path, wherein a Circuit Information Rate (CIR) is modified based on said predicted throughput to improve a TCP performance.
2. The method of claim 1 wherein said test packets and reply packets are sent at layer 2.
3. The method of claim 1 wherein said test packets and reply packets are sent at layer 3.
4. The method of claim 1 wherein a CIR is modified by increasing the CIR when the determined burst capacity of the network path divided by the determined roundtrip time for the network path is greater than the CIR.
5. The method of claim 1 , wherein modifying the CIR comprises reducing the CIR for the network path when the determined throughput is less than the CIR.
6. The method of claim 1 wherein determining the burst capacity of the network path includes performing a baselining step to ascertain an initial burst capacity of the network path, the baseline step including transmitting a number of test packets over the network path, the number of test packets based on the CIR.
7. The method of claim 1 wherein determining the round trip time comprises determining an average round trip time associated with the network path during the transmission of the number of test packets.
8. A system for predicting a throughput of a Transmission Control Protocol (TCP) path between a sender and a receiver over a network path, the system comprising:
a first TCP predictor on a first device transmitting a number of test packets over the network path; and
a second TCP on second device predictor receiving said number of test packets and sending reply packets to the first TCP predictor on the first device, said reply packets including a timestamp;
wherein said first TCP predictor on the first device determines a round trip time and a burst capacity of the network path based on said reply packets and predicts, the throughput of the network path based on said burst capacity divided by said roundtrip time of the network path, and wherein said first TCP is configured to modify a Circuit Information Rate (CIR) based on said predicted throughput to improve a TCP performance.
9. The system of claim 8 wherein the first TCP predictor determines if the throughout satisfies performance criteria associated with the network path.
10. The system of claim 8 wherein the first TCP predictor increases the CIR when the burst capacity of the network path divided by the roundtrip time for the network path is greater than the CIR.
11. The system of claim 8 wherein the first TCP predictor reduces the CIR for the network path when the determined throughput is less than the CIR.