application layer protocols

Analysis of Common Industrial Protocol Families: OPC and OPC DA Protocols in Industrial Control Systems

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Analysis of Common Industrial Protocol Families: OPC and OPC DA Protocols in Industrial Control Systems

Background of OPC Protocol Before the emergence of OPC, the industrial automation field faced a significant challenge: Diverse hardware devices: Factories have PLCs, DCS, instruments, sensors, drives, etc., from hundreds of different manufacturers. Diverse software requirements: There are monitoring software (SCADA/HMI), Manufacturing Execution Systems (MES), historical databases, ERP systems, etc., from different companies. Diverse communication … Read more

Introduction to Computer Network Technology

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Introduction to Computer Network Technology

Hello everyone. This is a new series. In this series, I will introduce you to concepts related to computer networking.Computer network technology is a mandatory subject for the spring college entrance examination, highlighting the importance of this field. Don’t be afraid. I will guide you to gradually understand it. Over time, you will learn this … Read more

How to Free FPGA Boards from JTAG Cable Constraints and Achieve Remote Programming Updates

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How to Free FPGA Boards from JTAG Cable Constraints and Achieve Remote Programming Updates

Accumulated FPGA Knowledge Points (19) How to Free FPGA Boards from JTAG Cable Constraints and Achieve Remote Programming Updates To free FPGA boards from JTAG cable constraints and achieve remote programming updates, the core idea is to “enable the FPGA system to receive update files over the network and write them into the configuration Flash”. … Read more

End-to-End Debugging of IoT (Objective Perspective)

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End-to-End Debugging of IoT (Objective Perspective)

Common Terminology Electrical Equipment PLC Local automation, process controllers On-site control for production lines, pump stations, gate stations, etc. RTU Data acquisition, communication Remote sensing stations for meteorology, hydrology, etc. Relay Sensor IoT Card May have directional or bound devices Protocols Hardware Protocols RS-485 OSI physical layer differential signal twisted pair, Usually 2-wire half-duplex or … Read more

Essential Security Certifications for IoT Devices

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Essential Security Certifications for IoT Devices

To sell wireless or IoT devices in the European Union, compliance with the Radio Equipment Directive (RED) is mandatory. RED not only focuses on radio frequency performance but also requires devices to have adequate protection measures in terms of network security, user privacy, and software updates. Overview of RED Certification • Scope: Wireless devices in … Read more

Comparison of the OSI Seven-Layer Model and the TCP/IP Four-Layer Model

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1. OSI Seven-Layer Model Core Idea: Layering and Encapsulation ·Layering: The complex communication process is divided into multiple smaller, more specialized layers. Each layer utilizes the services provided by the layer below and provides services to the layer above. ·Encapsulation: When sending data, the data moves from the upper layer to the lower layer, with … Read more

HTTP Smuggling: A Trust Crisis Triggered by ‘Parsing Differences’

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Introduction: The Invisible “Layer” In modern web architecture, an HTTP request from a user often passes through multiple checkpoints before reaching the actual business logic (backend server): CDN, load balancer, WAF, reverse proxy… We can imagine this model as a tightly secured building: Frontend Proxy (e.g., Nginx, CDN): This is your building’s “security guard”. He … Read more

The Dialogue of the Internet: A Deep Dive into HTTP and WebSocket

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In our daily web surfing, we rarely think about how browsers communicate with servers. This “dialogue” follows strict protocols, with HTTP and WebSocket being two of the most common “communication methods.” Today, we will delve into their differences and application scenarios. Basic Concepts: What are HTTP and WebSocket? HTTP (Hypertext Transfer Protocol) is the most … Read more

NPU Hardware Interface Signals and Communication Protocols

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The NPU (Neural Processing Unit), as a dedicated AI acceleration chip, requires its hardware interface design to meet the demands of high bandwidth, low latency, and flexible scalability. Below are the commonly used interface signals and corresponding protocols for NPUs at the hardware level, explained with actual chip examples: 1. Memory Interface Function: Connects to … Read more

An Overview of HTTP: Various Concepts and Protocols Related to HTTP

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What is HTTP? HTTP stands for Hypertext Transfer Protocol, which is an application layer protocol used for transmitting information between network devices. It is the foundation of the World Wide Web, enabling communication between browsers and servers to load web pages. In simple terms, when you open a browser and enter a URL, HTTP acts … Read more