The TCP protocol adopts a reliable transmission mechanism, which can ensure the reliability of data transmission, that is, to ensure the integrity, reliability and order of data. However, the TCP protocol is not completely free from packet loss.During network transmission, data packets may be lost due to network congestion, transmission link errors, buffer overflow and other reasons. For lost data packets, the TCP protocol will retransmit to ensure data integrity and reliability. Therefore, although the TCP protocol has certain reliability, it is not absolutely impossible to lose packets.In addition, it should be noted that the TCP protocol uses flow control and congestion controlMechanism, when the network is congested, TCP will reduce the sending rate and other means to avoid network congestion, so as to ensure the stability of the network and the reliability of data transmission. Therefore, when the network is congested, the performance of the TCP protocol may be affected to a certain extent, resulting in a delay in data transmission and an increase in the packet loss rate.