Congestion control method and network device

A congestion control method performed by a second network device to reduce congestion in a data center network, wherein the data center network comprises a first network device and a second network device, and the method comprises:

• receiving a first data flow sent by a first network device;
• determining an active flow quantity based on the first data flow received from the first network device;
• sending a first message to the first network device, wherein the first message carries the active flow quantity, wherein the first network device determines packet sending control information used to send a second data flow to the second network device based on the active flow quantity and a rated receiving bandwidth of the second network device;
• and
• receiving the second data flow sent by the first network device, wherein the sending of the second data flow is controlled by the first network device based on the packet sending control information, so that an actual receiving bandwidth of the second network device reaches the rated receiving bandwidth,
• wherein the determining, an active flow quantity based on the first data flow comprises:
• receiving, by the second network device, an initial packet in a first group of data packets sent by the first network device, and increasing a current active flow quantity by 1 to obtain a first active flow quantity;
• receiving, by the second network device, a tail packet in the first group of data packets sent by the first network device, and determining a first congestion value based on a quantity of data packets carrying an external congestion notification (ECN) identifier in the first group of data packets;
• and
• when the first congestion value is less than a congestion threshold, decreasing, by the second network device, the first active flow quantity by 1 to obtain a second active flow quantity;
• or
• when the first congestion value is greater than or equal to a congestion threshold, keeping, by the second network device, the first active flow quantity unchanged.

A first network device, comprising:

• a non-transitory memory storing instructions;
• and
• a processor coupled to the non-transitory memory;
• wherein the instructions, when executed by the processor, cause the first network device to be configured to:
• receive a first message sent by a second network device, wherein the first message carries an active flow quantity, and the active flow quantity is a quantity determined by the second network device based on a first data flow to which data packets received from the first network device belong;
• determine, based on the active flow quantity and a rated receiving bandwidth of the second network device, packet sending control information used to send a second data flow to the second network device;
• and
• send the second data flow to the second network device based on the packet sending control information, wherein the sending of the second data flow is controlled by the first network device based on the packet sending control information so that an actual receiving bandwidth of the second network device reaches the rated receiving bandwidth,
• wherein the instructions, when executed by the processor, further cause the first network device to be configured to:
• determine based on the active flow quantity, the rated receiving bandwidth of the second network device, and attribute information of the second data flow, the packet sending control information used to send the second data flow to the second network device, wherein
• the attribute information of the second data flow comprises at least one of application information of the second data flow and data volume information of the second data flow, the application information of the second data flow is used to indicate a service type to which a data packet of the second data flow belongs, and the data volume information of the second data flow is used to indicate a data volume of data packets that belong to the second data flow and that are send by the first network device within a preset time.

A second network device, comprising:

• a non-transitory memory storing instructions;
• and
• a processor coupled to the non-transitory memory;
• wherein the instructions, when executed by the processor, cause the second network device to be configured to:
• determine an active flow quantity based on a first data flow to which data packets received from a first network device belong;
• send a first message to the first network device, wherein the first message carries the active flow quantity, the active flow quantity and a rated receiving bandwidth of the second network device are used by the first network device to determine packet sending control information used to send a second data flow to the second network device;
• and
• receive based on the rated receiving bandwidth, the second data flow sent by the first network device, wherein the sending of the second data flow is controlled by the first network device based on the packet sending control information so that an actual receiving bandwidth of the second network device reaches the rated receiving bandwidth,
• wherein the instructions, when executed by the processor, further cause the second network device to be configured to:
• receive an initial packet in a first group of data packets sent by the first network device;
• increase a current active flow quantity by 1 to obtain a first active flow quantity;
• receive a tail packet in the first group of data packets sent by the first network device;
• and
• determine a first congestion value based on a quantity of data packets carrying an external congestion notification (ECN) identifier in the first group of data packets;
• and
• when the first congestion value is less than a congestion threshold, decrease the first active flow quantity by 1 to obtain a second active flow quantity, or
• when the first congestion value is greater than or equal to a congestion threshold, keep, by the second network device, the first active flow quantity unchanged.