NETWORK CONGESTION MANAGEMENT BASED ON COMMUNICATION DELAY

• US 20130100816A1
• Filed: 10/25/2011
• Published: 04/25/2013
• Est. Priority Date: 10/25/2011
• Status: Active Grant

• Current Assignee: Vmware LLC (Broadcom, Inc.)
• Original Assignee: VMware, Inc. (Broadcom, Inc.)
• Inventors: BERGAMASCO, Davide, AHMAD, Irfan
• Granted Patent: US 9,571,406 B2
• Time in Patent Office: Days
• US Class Current: 370/237
• CPC Class Codes: H04L 43/0864 Round trip delays
• CPC Class Codes: H04L 47/25 with rate being modified by the source upon detecting a change of network conditions
• 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 47/30 in combination with information about buffer occupancy at either end or at transit nodes

Abstract

Embodiments determine communication delay along a network path between a source and a destination in a network. A target injection rate is calculated based on the determined delay and a predetermined maximum queuing delay threshold. Data packets are transmitted along the network path using an inter-packet delay that is based on the target injection rate.

Claims

1. A system for managing network congestion between virtual machines, the system comprising:

a communication interface configured to;

transmit a message to a network destination; and

receive a response to the message from the network destination; and

a processor coupled to the communication interface and programmed to;

execute a first virtual machine (VM);

determine an instantaneous round trip time (RTT) corresponding to a network path between the system and the network destination based on the transmitted message and the received response;

calculate a target injection rate based on the determined RTT and a predetermined maximum queuing delay threshold; and

transmit a plurality of data packets from the first VM to a second VM via the communication interface using an inter-packet delay that is based on the calculated target injection rate.

2. The system of claim 1, wherein the processor is programmed to calculate the target injection rate based further on a previously determined target injection rate.

3. The system of claim 1, wherein the processor is further programmed to repeatedly calculate the target injection rate based on an RTT measurement interval.

4. The system of claim 1, wherein the processor is further programmed to calculate a target injection rate that is negatively correlated with the RTT.

5. The system of claim 1, wherein the processor is further programmed to calculate the target injection rate based further on a minimum injection rate representing a priority associated with the first VM.

6. The system of claim 1, wherein the processor is further programmed to configure a virtual network interface card (vNIC) associated with the first VM to transmit data packets from the first VM to the second VM based on the target injection rate.

7. The system of claim 1, wherein the communication interface is configured to transmit a message to the network destination by transmitting a message from the first VM to another VM.

8. A method comprising:

determining by a computing device a round trip time (RTT) representing a communication delay associated with a network path between a network source and a network destination;

calculating by the computing device a target injection rate based on the determined RTT, wherein the target injection rate is inversely proportional to the determined RTT; and

transmitting by the computing device a plurality of data packets along the network path using an inter-packet delay that is based on the target injection rate.

9. The method of claim 8, wherein determining the RTT comprises:

transmitting a frame to the network destination, wherein the transmitted frame elicits a transmission of an echo frame from the network destination;

receiving the echo frame from the network destination; and

calculating an elapsed time between said transmitting and said receiving.

10. The method of claim 8, wherein determining the RTT comprises:

adding a transmission timestamp to a network packet that is addressed to the network destination, wherein the transmission timestamp represents a current time when the transmission timestamp is added to the network packet;

transmitting the network packet to the destination;

receiving a response to the network packet, wherein the response includes the transmission timestamp; and

determining an elapsed time between the transmission timestamp from the received response and a current time.

11. The method of claim 8, wherein calculating the target injection rate comprises calculating the target injection rate based further on a previously determined target injection rate.

12. The method of claim 8, wherein calculating the target injection rate comprises combining a current calculation with a previously determined target injection rate using a weighted moving average.

13. The method of claim 12, wherein the weighted moving average is based on a responsiveness parameter representing a weight to apply to the current calculation, said method further comprising:

calculating a queuing delay based on the RTT; and

adjusting the responsiveness parameter based on a quantity of times the queuing delay violates a threshold value.

14. The method of claim 8, wherein calculating the target injection rate comprises calculating the target injection rate based further on a minimum injection rate associated with one or more of the following:

the network source and the network path.

15. The method of claim 8, wherein calculating the target injection rate comprises calculating a latency ratio based on a current queuing delay and a predetermined maximum queuing delay threshold.

16. One or more computer-readable storage media embodying computer-executable components, said components comprising:

a measurement component that when executed causes at least one processor to determine a round trip time (RTT) measured along a network path; and

a rate control component that when executed causes at least one processor to;

determine a queuing delay based on the RTT;

calculate a latency ratio based on the queuing delay and a predetermined maximum queuing delay threshold;

calculate a target injection rate based on the latency ratio; and

transmit a plurality of data packets along the network path using an inter-packet delay that is based on the target injection rate.

17. The computer-readable storage media of claim 16, wherein the rate control component causes the processor to calculate the queuing delay based further on a minimum observed queuing delay associated with the network path, and wherein the calculated queuing delay and the minimum observed queuing delay represent elapsed times.

18. The computer-readable storage media of claim 16, wherein the rate control component causes the processor to calculate the target injection rate based further on a minimum injection rate.

19. The computer-readable storage media of claim 16, wherein the rate control component causes the processor to calculate the target injection rate based further on a previously calculated target injection rate.

20. The computer-readable storage media of claim 16, wherein the rate control component causes the processor to transmit data packets using an inter-packet delay that is based on the target injection rate at least in part by delaying packets transmitted by a virtual machine.

21. A system comprising:

a memory for storing a previous target injection rate representing a rate at which data packets are to be transmitted along a network path;

a processor coupled to the memory and programmed to;

calculate a raw injection rate based on the previous target injection rate, a latency ratio representing a queuing delay, and a minimum injection rate; and

calculate a current target injection rate by combining the previous target injection rate and the raw injection rate as a weighted average using a responsiveness parameter that represents a weight to apply to the raw injection rate; and

a communication interface configured to transmit a plurality of data packets along the network path based on the current target injection rate.

22. The system of claim 21, wherein the processor is further programmed to:

determine a quantity of times the queuing delay violates a predetermined threshold value to create a violation count; and

adjust the responsiveness parameter when the violation count exceeds a predetermined maximum violation count.

23. The system of claim 21, wherein the processor is further programmed to:

determine a quantity of times the queuing delay is greater than a predetermined maximum queuing delay threshold to create a violation count; and

decrease the responsiveness parameter when the violation count exceeds a predetermined maximum violation count.

24. The system of claim 21, wherein the processor is further programmed to:

determine a quantity of times the queuing delay is equal to zero to create a violation count; and

increase the responsiveness parameter when the violation count exceeds a predetermined maximum violation count.

25. The system of claim 21, wherein the processor is further programmed to calculate an inter-packet delay based on the current target injection rate, and the communication interface is configured to transmit the data packets using the inter-packet delay.