Introduction: This article aims to discuss knowledge about TCP. Please forgive any inappropriate metaphors. In the fourth year of the Tianqi era of the Ming Dynasty, early morning. As dawn broke, I drove a horse-drawn cart full of goods to the South City Gate, which was the central location for handling goods. A line of … Read more
Currently, there are many network protocols built on the TCP protocol, such as telnet, ssh, ftp, http, etc. These protocols can be roughly divided into two categories based on data throughput: (1) Interactive data types, such as telnet and ssh. These types of protocols usually only do small-scale data exchanges, such as pressing a key … Read more
The italic part is a question from the reader After reading Richard Stevens’ TCP/IP Protocol Volume 1: Detailed Explanation for a long time, I feel that it is quite difficult to read. How should I learn what the TCP/IP protocol is really about? What can I do after understanding the TCP/IP protocol? I would appreciate … Read more
Click the “IT Program Circle” above to select “Top Public Account”. Source: Zhang Godan’s Technical Journey Since I learned about the TCP/IP congestion control algorithm last time, I increasingly wanted to delve deeper into some underlying principles of TCP/IP. I searched a lot of information online and found a column by Tao Hui on high-performance … Read more
Brief Introduction to UDP UDP is a transport layer protocol, sitting in the same layer as the TCP protocol. However, unlike TCP, UDP does not provide features such as timeout retransmission or error retransmission, meaning it is an unreliable protocol. UDP Protocol Header UDP Port Number Many applications require the use of UDP, so it … Read more
From: Juejin, Author: Ruheng Link: https://juejin.im/post/6844903490595061767 1. TCP/IP Model The TCP/IP protocol model (Transmission Control Protocol/Internet Protocol) consists of a series of network protocols that form the foundation of the Internet and are the core protocols of the Internet. The reference model based on TCP/IP divides protocols into four layers: Link Layer, Network Layer, Transport … Read more
1. Introduction As application layer developers, the network protocol we most often encounter is typically the transport layer’s TCP (another important protocol at this layer is UDP). However, when it comes to the IP protocol, application programmers are more familiar with the concept of an IP address, and it becomes difficult to delve deeper. This … Read more
Introduction Today, let’s discuss Modbus, starting with the main content of today: 01 Terminology Interpretation 02 Background 03 Protocol Principles 04 Transmission Methods 05 Differences Between Modbus RTU and Modbus ASCII 06 Modbus TCP and Its Considerations 07 Function Code Roles 08 Security Analysis of Modbus Protocol 01 Terminology Interpretation Checksum: A checksum is typically … Read more
【Introduction】MODBUS TCP instruction V6.0 adds Modbus client function code 23, which allows reading and writing one or more holding registers from the server in a single request operation, eliminating the programming workload of polling and improving work efficiency. Join the exclusive group for electrical automation technology exchange Join the exclusive group for electrical automation procurement … Read more
This chapter mainly introduces the MODBUS TCP communication protocol and the content of free format communication protocols. 1. Overview of MODBUS TCP Communication MODBUS TCP combines the Ethernet physical network and the network standard TCP/IP with MODBUS as the application protocol standard for data representation. MODBUS TCP communication messages are encapsulated in Ethernet TCP/IP packets, … Read more