What is the difference between SMS channel 1 confirmation and 2 confirmation? Seek professional answers

Among the TCP/IP protocols, TCP provides reliable connection service, and three-way handshake is adopted to establish the connection.

The first handshake: when establishing a connection, the client sends a syn packet (syn=j) to the server and enters the SYN_SEND state, waiting for the server to confirm;

Second handshake: when the server receives the syn packet, it must confirm the SYN of the customer (ACK = J+1) and send a SYN packet (syn=k) by itself, that is, SYN+ACK packet. At this time, the server enters SYN_RECV state;

Three-way handshake: The client receives the SYN+ACK packet from the server and sends an acknowledgement packet ACK(ack=k+ 1) to the server. After this package is sent out, the client and the server enter the establishment state and complete the three-way handshake.

After completing the three-way handshake, the client and the server begin to transmit data.