TCP (Transmission Control Protocol) is a reliable connection-oriented protocol that ensures reliable data transmission in the following ways:
1. Confirmation and retransmission mechanism: When the receiver receives the data, it will send a confirmation message to the sender, telling it that the data has been received. If the sender does not receive an acknowledgment, it retransmits the data until the receiver receives the data and sends an acknowledgment.
2. Serial number and confirmation number: TCP assigns a serial number and confirmation number to each data segment. The serial number is used to identify the position of the data segment, and the confirmation number is used to confirm the position of the received data segment, which can avoid Data is missing or out of sequence.
3. Flow control: TCP uses the sliding window protocol to control the rate at which the sender sends data. The receiver will tell the sender its buffer size, and the sender will control the sending rate according to the buffer size of the receiver to ensure that the receiver does not Will lose data because it is too fast.
4. Congestion control: TCP uses congestion windows to control network congestion. When the network is congested, TCP will reduce the sending rate to avoid excessive data packets causing network congestion.
Through the above mechanisms, TCP guarantees the reliable transmission of data, but it will also cause a certain delay, because the data packet needs to wait for confirmation and retransmission, and the sliding window and congestion control will limit the sending rate.