Data transmission method, device and system

A data transmission method, comprising:nobtaining a current queue length of a queue corresponding to an output port;when the current queue length meets a back-pressure requirement, determining a back-pressure priority corresponding to the current queue length according to the current queue length and a mapping relationship between a preset queue length and the back-pressure priority, and generating back-pressure information, wherein the back-pressure information inhibits a line card to send data with a data priority less than or equal to the back-pressure priority to the output port; wherein the mapping relationship between the preset queue length and the back-pressure priority is a mapping relationship between the preset queue length and the back-pressure priority or a mapping relationship between a queue length interval and the back-pressure priority; andsending the back-pressure information to a line card to prevent the card from sending the data with the data priority less than or equal to the back-pressure priority to the output port after receiving the back-pressure information;wherein if the mapping relationship between the preset queue length and the back-pressure priority is the mapping relationship between the queue length value and the back-pressure priority, the determining the back-pressure priority corresponding to the current queue length comprises: querying the mapping relationship, and obtaining a back-pressure priority corresponding to a value of the current queue length; andif the mapping relationship between the preset queue length and the back-pressure priority is the mapping relationship between the queue length interval and the back-pressure priority, the determining the back-pressure priority corresponding to the current queue length comprises: querying the mapping relationship, and obtaining a back-pressure priority corresponding to a queue length interval where the current queue length resides.

A data transmission device, comprising:na current queue length obtaining module, configured to obtain a current queue length of a queue corresponding to an output port;a back-pressure information generation module, configured to, when the current queue length meets a back-pressure requirement, determine a back-pressure priority corresponding to the current queue length according to the current queue length and a mapping relationship between a preset queue length and the back-pressure priority, and generate back-pressure information, wherein the back-pressure information inhibits a line card from sending data with a data priority less than or equal to the back-pressure priority to the output port; wherein the mapping relationship between the preset queue length and the back-pressure priority is a mapping relationship between a queue length value and the back-pressure priority or a mapping relationship between a queue length interval and the back-pressure priority; anda back-pressure information sending module, configured to send the back-pressure information to a line card to prevent the card from sending the data with the data priority less than or equal to the back-pressure priority to the output port after receiving the back-pressure information;wherein if the mapping relationship between the preset queue length and the back-pressure priority is the between the queue length value and the back-pressure priority, the back-pressure information generation module further comprises: a back-pressure priority corresponding to a queue length value obtaining unit, configured to query the mapping relationship, and obtain a back-pressure priorty corresponding to a value of the current queue length; andif the mapping relationship between the preset queue length and the back-pressure priority is the mapping relationship between the queue length interval and the back-pressure priority, the back-pressure information generation module further comprises:a back-pressure priority corresponding to a queue length interval obtaining unit, configured to query the mapping relationship, and obtain a back-pressure priority corresponding to a queue length interval where the current queue length resides.

A data transmission system, comprising: a line card and a data transmission device, characterized in that whereinnthe line card is configured to send data to the data transmission device, and transmit data according to back-pressure information sent by the data transmission device; andthe data transmission device is configured to obtain a current queue length of a queue corresponding to an output port; when the current queue length meets a back-pressure requirement, determine a back-pressure priority corresponding to the current queue length according to the current queue length and a mapping relationship between a preset queue length and the back-pressure priority, and generate back-pressure information, wherein the back-pressure information inhibits a line card from sending data with a data priority less than or equal to the back-pressure priority to the output port; wherein the mapping relationship between the preset queue length and the back-pressure priority is a mapping relationship between a queue length value and the back-pressure priority or a mapping relationship between a queue length interval and the back-pressure priority; and send the back-pressure information to a line card to prevent the line card from sending the data with the data priority less than or equal to the back-pressure priority to the output port after receiving the back-pressure information;wherein if the mapping relationship between the preset queue length and the back-pressure priority is the mapping relationship between the queue length value and the back-pressure priority, the determining the back-pressure priority corresponding to the current queue length comprises: querying the mapping relationship, and obtaining a back-pressure priority corresponding to a value of the current queue length; andif the mapping relationship between the preset queue length and the back-pressure priority is the mapping relationship between the queue length interval and the back-pressure priority, the determining the back-pressure priority corresponding to the current queue length comprises: querying the mapping relationship, and obtaining a back-pressure priority corresponding to a queue length interval where the current queue length resides.