OSI Layer-7 model and TCP/IP layer-4 Model

OSI Layer-7 Model

OSI: Open System Interconnection Reference Model
Proposed by ISO in 1984, the objective is to establish a general network standard.

Application Layer
Provides user interfaces for users to access the network.
For example, email, WWW, and network file access.
Session Layer
Manage sessions between computers
Implement inter-computing session control
Presentation Layer
Data format conversion
Compression and decompression
Encryption and decryption
Transport Layer
Reliable/unreliable data transmission between computers
Implement Flow Control
Conduct Error Detection
Ensure the correctness of transmitted data
Network Layer
Provide the computer's logical address (for example, IP address)
Path Selection
Data Link Layer
Merge bit streams (BITs) into bytes (bytes)
Note: 1 byte = 8 bits
Provide the physical address of the computer (MAC address)
Error Detection
Physical Layer
Define Mechanical and Electrical Properties of transmission media
Define electrical characteristics of a pin-out connector
Transmission bit stream (BITs)
Data link layer Traffic Control

TCP/IP layer-4 Model

The TCP/IP model originated from ARPANET.
Current TCP/IP is a potential Standard

Application Layer
Corresponding to the top three layers of OSI, including a large number of protocol implementations for network users.
For example, telnet, FTP, SMTP, HTTP, SNMP, and DNS.

Transport Layer
Corresponds to the OSI transport layer and provides end-to-end connections between the source and target hosts. The typical protocol is TCP.

Network Layer
Corresponds to the OSI network layer, effectively solving the problem of interconnection between different network types. The network layer is designed with high efficiency and conciseness. It provides unreliable connectionless services and delivers them as much as possible. The typical protocol is IP.

Network Interface Layer
Corresponding to the lower two layers of the OSI reference model, you must support the IP protocol without detailed definitions.

 

Comparison between TCP/IP and OSI Models