Catalog

udp Characteristics of the agreement

UDP Possible problems and solutions of transmission

TCP Characteristics of the agreement

TCP Possible problems and solutions of transmission

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udp Characteristics of the agreement

（1） There is no connection

         UDP The communication parties do not need to communicate before data occurs , The client only needs to know the name of the server IP Address and port number can send data

（2） Transmission is unreliable

          There is no guarantee that the data is reliable and reaches the opposite end in an orderly manner .

（3） For datagram

         udp For the application layer and transport layer, the whole data is delivered when the data is submitted .

UDP Possible problems and solutions of transmission

（1） The reason for this problem ：udp The length of the datagram is 65535 byte , But if the data to be transmitted is greater than 65535 byte             Then problems will be encountered in the transmission process .

（2） Solution steps ： Design application layer protocol （ Custom protocol fields ） Field

         a、 Data belonging to the same application layer is cut into different blocks , because udp Transmission is not reliable , So add the same... To different data modules id.

         b、udp The transmission does not arrive at the opposite end in an orderly way , Add an offset to the header , The offset is used to describe the position of block data in the whole application layer packet .

         c、 Add the length of block data to the header data .

TCP Characteristics of the agreement

（1） Connection oriented

         TCP Before sending data, both parties need to establish a connection , To send data

（2） Reliable transmission

         TCP Ensure that the data reaches the opposite end reliably and orderly during transmission .

（3） Byte stream oriented

         a、 There is no obvious boundary between the transmitted data

         b、 For the receiver, when data can be received , That can receive any byte of data .

TCP Possible problems and solutions of transmission

（1） The cause of the problem ：TCP The protocol is byte stream oriented , It will cause packet sticking problem during transmission , Difficult to distinguish data             length .

（2） resolvent ： Application layer self customization protocol , Custom protocol adds header （ Data length ） And separator

         a、[ Fixed length header ] + Data and information

         b、[ Fixed length Baotou ] + Data and information + Separator

         c、[ Variable length header ]  + data + Separator