TCP and UDP transport layer

 TCP protocol
        Transmission Control Protocol
        TCP is a connection-oriented, reliable process to process communication protocol
        TCP provides full-duplex engineering services, namely, data can be transmitted at the same time two-way
        handshake three times:
                the process of establishing connection
                initiated by the client
        four times off :
                 disconnection process connection
                 initiated by the server

                  Seq: SEQ ID nO
                   ACK: acknowledgment number
                           realize retransmission

pointer bits: a two-bit system, 0 and only the two values 1, 1 indicates enabled 0 indicates not enable
        the SYN: synchronization bit
                SYN = 1, represents a new connection
        ACK: acknowledge bit
                 ACK = 1, represents confirmation data
        FIN: end bit
                 FIN = 1, represents a disconnect request

        TCP segment
                TCP to several bytes constitute a branch, called the segment

UDP:
       User Datagram Protocol
       unreliable connectionless service
       transmission 512 is a fixed size, additional assistance is completed by an upper

 

 

 

                                                      TCP three-way handshake

 

 

                                                                            TCP first handshake

 

 

                                                                              TCP second handshake

 

 

                                                                      TCP third handshake

 

 

                                                    TCP four wave