Reference: Network OSI seven-layer model and functions of each layer and TCP/IP
network OSI seven-layer model and functions of each layer
1. OSI seven-layer model
- Application layer : Provide users with commonly used applications, and each network application corresponds to a different protocol. For example, file transportation access and management, email, etc. HTTP SMTP
- Presentation layer : Mainly responsible for data format conversion, ensuring that messages sent by the application layer of one system can be read by the application layer of another system; data encryption
- Session layer : responsible for the establishment of two nodes in the network, maintaining the communication connection between the two computers in the computer network during data transmission, and deciding when to terminate the communication (establish or release the connection with other nodes)
- Transport layer : Realize end-to-end reliable communication between two user processes, and handle transmission problems such as packet errors. TCP UDP
- Network layer : logical address addressing to realize path selection between different networks (select routing for data packets) IP ARP
- Data link layer : Establish logical connections and perform hardware address addressing
- Physical layer : mainly physical medium transmission medium (network cable or wireless), which transmits data on physical medium in the form of binary data
Supplement: MAC address and IP address in computer network.
Physical address is the address used by the data link layer and the physical layer, and is the unique identification of network equipment; IP address is the address used by the network layer and above. What kind of mac address is filled in is done by the address resolution protocol (ARP) of the network layer.
2、TCP/IP
- Application layer (application layer, presentation layer, session layer)
- Transport layer
- Network layer
- Network interface layer (data link layer, physical layer)