Package 4: The first data sent by the server to the client, 15 bytes.The first packet is that the client initiates a connection to the server and declares that its receiving window is 20 bytes.The second packet is the ACK+SYN returned by the server, and also declares its own receiving window of 29200 bytes.The third packet is the client's reply to the server's ACK, and the interface window is still 20 at this time.After that, normal data transmission and reception begins. Packets 1~3: The three-way handshake process.After the other party receives it, it will limit its to the specified size.If its own processing capacity is limited and its receive buffer is full, the sender should stop sending data when the receive window size is 0.įor example, in the TCP packet generated by the simulation tool, the client window is declared as 20, and the packet capture is as follows: Usually, win in the wireshark capture means to declare the size of its receiving window to the other party.

Mainly divided into: sent and confirmed packets (not read by the application layer).Unacknowledged packets are sent, sendable packets are not sent, and unsendable packets are not sent.Among them, the sliding window refers to the size of the unacknowledged and unsent sendable areas.

Let’s talk about the principle firstĪs far as the sender is concerned, it is generally as follows: I have learned more about the TCP protocol in the past six months, so I want to update some of the content of the TCP protocol.Today, let's start with the sliding window in the TCP protocol. The TCP protocol is a very interesting content.

Wireshark tcp retransmission