Congestion control method and network device

1. A method, comprising:

transmitting, by a network device, traffic in a first period and a second period, wherein the traffic is transmitted based on a first threshold in the first period and based on a second threshold in the second period, the first period is earlier than the second period, and the second threshold is equal to a sum of the first threshold and a first fixed value;

obtaining, by the network device, a first average traffic load of a queue in the first period and a second average traffic load of the queue in the second period;

determining, by the network device, when the second period ends, a third threshold based on a difference and a target increase value, wherein the difference is obtained by subtracting the first average traffic load from the second average traffic load, and the target increase value is greater than zero;

marking, by the network device, a received packet when a quantity of packets buffered in the queue is greater than the third threshold, and queueing the marked packet in the queue, wherein the marked packet indicates that congestion occurs; and

sending, by the network device to a receiving device, the marked packet when the marked packet is dequeued from the queue.

2. The method according to claim 1 , wherein determining the third threshold based on the difference and the target increase value comprises:

when the difference is greater than the target increase value, determining the third threshold to be equal to the second threshold.

3. The method according to claim 1 , wherein determining the third threshold based on the difference and the target increase value comprises:

when the difference is not greater than the target increase value and the difference is not less than a target decrease value, determining the third threshold to be less than the second threshold.

4. The method according to claim 3 , wherein the third threshold is equal to the first threshold.

5. The method according to claim 1 , wherein determining the third threshold based on the difference and the target increase value comprises:

when the difference is not greater than the target increase value and the difference is less than the target decrease value, determining the third threshold to be a product of the second threshold and a ratio of the second average traffic load to the first average traffic load.

6. The method according to claim 1 , wherein determining the third threshold based on the difference and the target increase value comprises:

when the difference is less than a target decrease value and less than the target increase value, determining the third threshold to be a product of the second threshold and a ratio of the second average traffic load to the first average traffic load.

7. The method according to claim 1 , wherein determining the third threshold based on the difference and the target increase value comprises:

when the difference is greater than the target increase value, determining the third threshold to be equal to a sum of the second threshold and a second fixed value.

8. The method according to claim 7 , wherein the first fixed value is equal to the second fixed value.

9. The method according to claim 1 , wherein determining the third threshold based on the difference and the target increase value comprises:

calculating a comparison threshold based on a fourth average traffic load of the queue in a fourth period and the target increase value, where the second period comprises the fourth period; and

determining the third threshold based on a smaller value between the comparison threshold and the second threshold.

10. The method according to claim 9 , where the comparison threshold is a product of the fourth average traffic load and a predetermined value.

11. A network device, comprising:

a processor; and

a network interface, configured to:

transmit traffic in a first period and a second period, wherein the traffic is transmitted based on a first threshold in the first period and based on a second threshold in the second period, the first period is earlier than the second period, and the second threshold is equal to a sum of the first threshold and a first fixed value;

wherein the processor is configured to:

obtain a first average traffic load of a queue in the first period and a second average traffic load of the queue in the second period;

determine, when the second period ends, a third threshold based on a difference and a target increase value, wherein the difference is obtained by subtracting the first average traffic load from the second average traffic load, and the target increase value is greater than zero; and

mark a received packet when a quantity of packets buffered in the queue is greater than the third threshold, and queue the marked packet in the queue, wherein the marked packet indicates that congestion occurs; and

wherein the network interface is configured to:

send, to a receiving device, the marked packet when the marked packet is dequeued from the queue.

12. The network device according to claim 11 , wherein the processor being configured to determine the third threshold based on the difference and the target increase value comprises the processor being configured to:

when the difference is greater than the target increase value, determine the third threshold to be equal to the second threshold.

13. The network device according to claim 11 , wherein the processor being configured to determine the third threshold based on the difference and the target increase value comprises the processor being configured to:

when the difference is not greater than the target increase value and the difference is not less than a target decrease value, determine the third threshold to be less than the second threshold.

14. The network device according to claim 13 , wherein the third threshold is equal to the first threshold.

15. The network device according to claim 11 , wherein the processor being configured to determine the third threshold based on the difference and the target increase value comprises the processor being configured to:

when the difference is not greater than the target increase value and the difference is less than the target decrease value, determine the third threshold to be a product of the second threshold and a ratio of the second average traffic load to the first average traffic load.

16. The network device according to claim 11 , wherein the processor being configured to determine the third threshold based on the difference and the target increase value comprises the processor being configured to:

when the difference is less than a target decrease value and less than the target increase value, determine the third threshold to be a product of the second threshold and a ratio of the second average traffic load to the first average traffic load.

17. The network device according to claim 11 , wherein the processor being configured to determine the third threshold based on the difference and the target increase value comprises the processor being configured to:

when the difference is greater than the target increase value, determine the third threshold to be equal to a sum of the second threshold and a second fixed value.

18. The network device according to claim 17 , wherein the first fixed value is equal to the second fixed value.

19. The network device according to claim 11 , wherein the processor being configured to determine the third threshold based on the difference and the target increase value comprises the processor being configured to:

calculate a comparison threshold based on a fourth average traffic load of the queue in a fourth period and the target increase value, where the second period comprises the fourth period; and

determine the third threshold based on a smaller value between the comparison threshold and the second threshold.

20. The network device according to claim 19 , wherein the comparison threshold is a product of the fourth average traffic load and a predetermined value.