"Java Learning" network programming 1

Interaction of two hosts on the network

① find the other host based on IP

② data is sent to the application specified by the other party, in order to represent these applications, the concept of port is introduced.

Common ports:

Wed Port 80

MySQL Port 3306

Valid Port 0~65535

③ defines a communication rule, called a protocol. International organizations define the common protocol TCP/IP protocol

Local loopback address: 127.0.0.1 (IP address If this machine does not have IP address) (if ping this address does not pass, indicating a problem with the NIC) hostname: localhost

Common transport protocols: TCP,UDP

Network model

OSI layer Seven model: Application Layer Presentation Layer Session Layer Transport Layer Network layer Data Link layer physical layer

TCP/IP four Layer model: Application Layer Transport Layer Network layer network layer to host layer

"Java Learning" network programming 1