Ethernet half-duplex retransmission method and system

Abstract

The invention discloses an Ethernet half-duplex retransmission method and system, and belongs to the technical field of communication. The method comprises the steps of: S1, recording the number of collision times when collision occurs in a half-duplex communication network; S2, judging the parity of the impact times, namely if the impact times meet a first preset condition, setting avoidance time as first preset time and setting the range of the first preset time to be 512-1024 bit time, and if the number of impact times meets a second preset condition, setting the avoidance time to be second preset time and setting the range of the second preset time to be 96-512 bit time; and S3, resending communication data according to the avoidance time. The Ethernet half-duplex retransmission method has the beneficial effects that when collision occurs, through parity judgment of collision times and configuration of the avoidance time, the situation that a bus is continuously occupied by a certain end due to poor quality of a random mechanism of the certain end is avoided, the number of collision times is reduced, continuous data transmission on a communication line can be basically maintained, and the utilization rate of the line is improved.

Description

technical field [0001] The invention relates to the technical field of communication, in particular to an Ethernet half-duplex retransmission method and system. Background technique [0002] Half-duplex communication (Half-duplex Communication) can realize two-way communication, but it cannot be carried out in two directions at the same time, and must be carried out alternately. That is to say, each segment of the communication channel can be the sending end or the receiving end; but at the same time, information can only have one transmission direction. [0003] In network data transmission, such as figure 1 As shown, the Ethernet network 1a and the Ethernet network 2a work in half-duplex mode. When both ends of the communication channel send data at the same time, the communication will be abnormal, which is a collision behavior. After the data collides, it needs to be restarted. Transmission (that is, retransmission), the current industry standard retransmission method ...

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Problems solved by technology

[0004] Assume that through 10M half-duplex communication, the clock cycle is 400ns, and 4 bits are transmitted in one clock cycle, then the 512bit time is 51.2us. If the avoidance time is calculated according to the above method to retransmit the data, for example, the randomness after the 5th power of 2 is randomized The data is 30, 30 multiplied by 512bit (ie 51.2us) equals 153.6us. During this time, the network communication channel is idle, which will waste bandwidth. If it is random data within the range of 2 to the power of 10, it will waste more time. For example, in extreme cases, both ends may need to wait for 2 10 *512bit time, approximately equal to 500ms

In addition, this method cannot guarantee the quality of the random mechanism used by the Ethernet ports at both ends. When the quality of the random mechanism of the Ethernet port at one end is poor, the data is also randomly generated within the power of 2, and the resulting The random data may always be too large or too small, so that once a collision occurs, one end always seizes the bus and retransmits first, and continues to occupy the bus. Therefore, it is urgent to design an Ethernet half-duplex retransmission transmission method and system to meet the needs of actual use

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