The OSI model is an open system interconnection communication reference model. It is a conceptual model proposed by the International Organization for Standardization. It is a standard framework that attempts to interconnect various computers into networks around the world.
The operating environment of this tutorial: Windows 7 system, Dell G3 computer.
What is the OSI model?
Open System Interconnection Reference Model (English: Open System Interconnection Reference Model, abbreviated as OSI), referred to as OSI model (OSI model), a conceptual model proposed by the International Organization for Standardization. A standard framework that attempts to interconnect various computers into networks around the world. Defined in ISO/IEC 7498-1.
Level division
According to recommendation X.200, OSI divides the computer network architecture into the following seven layers, labeled 1 to 7, with layer 1 at the bottom. Now "OSI/RM" is the abbreviation of "Open Systems Interconnection Reference Model" in English.
Layer 7 Application Layer
Main entry: Application layer
Application Layer provides application software An interface designed to set up communication with another application software. For example: HTTP, HTTPS, FTP, TELNET, SSH, SMTP, POP3, etc.
The 6th layer of presentation layer
Main article: Presentation layer
The presentation layer (Presentation Layer) converts the data into A format that is compatible with the recipient's system format and suitable for transmission.
Layer 5 Session Layer
Main entry: Session Layer
The Session Layer is responsible for data transmission Sets up and maintains communication connections between two computers in a computer network.
Layer 4 Transport Layer
Main entry: Transport layer
Transport Layer (Transport Layer) puts the transport header (TH) is added to the data to form a packet. The transmission header contains sending information such as the protocol used. For example: Transmission Control Protocol (TCP), etc.
Layer 3 Network Layer
Main entry: Network Layer
The Network Layer determines the path of data Select and forward, adding a network header (NH) to the packet to form a packet. The network header contains network data. For example: Internet Protocol (IP), etc.
Layer 2 Data Link Layer
Main article: Data Link Layer
Data Link Layer Link Layer) is responsible for network addressing, error detection and error correction. Frames are formed when headers and trailers are added to the packet. The data link header (DLH) contains the physical address and error detection and correction methods. The Data Linked List (DLT) is a string indicating the end of the packet. Examples include Ethernet, Wireless LAN (Wi-Fi), and General Packet Radio Service (GPRS).
It is divided into two sub-layers: logical link control (LLC) sub-layer and media access control (MAC) sub-layer.
Layer 1 Physical Layer
Main entry: Physical Layer
Physical Layer (Physical Layer) is uploaded on the local LAN Send data frame (data frame), which is responsible for managing the intercommunication between computer communication equipment and network media. Includes pinouts, voltages, cable specifications, hubs, repeaters, network cards, host adapters, and more.
For more related knowledge, please visit the FAQ column!
The above is the detailed content of What is the OSI model. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

Dreamweaver Mac version
Visual web development tools

WebStorm Mac version
Useful JavaScript development tools

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),
