Table of Contents What is eSIM eSIM Development Background and Industry Trends 2.1 Limitations of Traditional SIM Cards 2.2 The Emergence of eSIM eSIM Working Principles and Technical Architecture 3.1 Core Components of eSIM 3.2 Workflow Overview Comparison Between eSIM and Traditional SIM Cards Main Application Scenarios of eSIM 5.1 Consumer Electronics 5.2 IoT and M2M Applications 5.3 Industrial Internet of Things (IIoT) 5.4 Connected Vehicles and Smart Transportation Core

Table of Contents What is the MQTT Protocol? 1.1 MQTT's Design Philosophy & Key Features 1.2 Why is MQTT Indispensable in IoT/IIoT? Basic Principles and Workflow of MQTT 2.1 Publish/Subscribe Pattern: Evolution from IBM MQ Series 2.2 Detailed Explanation of MQTT Packet Structure 2.3 MQTT 3.1, 3.1.1, 5.0: Version Differences & Migration Guide 2.4 MQTT Application Scenarios in IoT (Modbus/MQTT/OPC UA Integration Explained) Detailed Understanding of MQTT Protocol Architecture 3.