もっと例文: 1 2
- The server then subtracts 1 from the acknowledgement number to reveal the SYN cookie sent to the client.
- When a client sends back a TCP ACK packet to the server in response to the server's SYN + ACK packet, the client MUST ( according to the TCP spec ) use " n + 1 " in the packet's " Acknowledgement number ", where " n " is the initial sequence number sent by the server.
- Duplicate acknowledgement is the basis for the fast retransmit mechanism which works as follows : after receiving a packet ( e . g . with sequence number 1 ), the receiver sends an acknowledgement by adding 1 to the sequence number ( i . e ., acknowledgement number 2 ) which means that the receiver received the packet number 1 and it expects packet number 2 from the sender.
- The fast retransmit enhancement works as follows : if a TCP sender receives a specified number of acknowledgements which is usually set to three duplicate acknowledgements with the same acknowledge number ( that is, a total of four acknowledgements with the same acknowledgement number ), the sender can be reasonably confident that the segment with the next higher sequence number was dropped, and will not arrive out of order.
- One of the most important factors of three-way handshake is that, in order to exchange the starting sequence number the two sides plan to use, the client first sends a segment with its own initial sequence number x, then the server responds by sending a segment with its own sequence number y and the acknowledgement number x + 1, and finally the client responds by sending a segment with acknowledgement number y + 1.