SIG MESH
1. Introduction
With the rapid development of Internet of Things (IoT) technology, Bluetooth SIG Mesh (Bluetooth Special Interest Group Mesh), as an emerging wireless network protocol, is gradually becoming an important solution for connecting smart devices. SIG Mesh, with its high efficiency, flexibility and powerful features, has shown broad application prospects in smart homes, smart cities and other fields. This article will deeply analyze the working principle and core advantages of SIG Mesh.
2. Introduction to SIG Mesh
SIG Mesh is a mesh network protocol based on Bluetooth technology, developed and maintained by the Bluetooth Special Interest Group (Bluetooth SIG). It allows hundreds or even thousands of Bluetooth devices to connect to each other through a mesh network, forming a wireless Internet of Things with wider coverage and higher stability. SIG Mesh realizes flexible interconnection and data transmission between devices through multi-hop communication and broadcast mechanisms.
3. Working principle of SIG Mesh
The working principle of SIG Mesh is mainly based on the flooding protocol, which realizes the full network coverage of data through broadcasting and relaying between nodes. Its workflow is roughly as follows:
Data initiation: A control or read type data packet is sent by a smartphone or other control terminal (Provisioner), and the target is a specific node A.
Broadcast message: After node A receives the data packet, it will broadcast it so that all surrounding nodes can receive it.
Relay forwarding: When node B receives the message from node A, it will broadcast the message again, forming a "one to ten, ten to a hundred" infectious propagation method until all devices within the wireless range receive the message.
Data encryption: During the entire process, SIG Mesh will perform multi-layer encryption on the data in the network, including the network layer key (NetworkKey) and the application key (AppKey), to ensure the security of data transmission.
4. SIG Mesh Architecture and Layers
The SIG Mesh protocol stack is divided into seven layers, from bottom to top: Bearer, Network, Lower Transport, Upper Transport, Access, Foundation Model, and Model. Each layer has its specific functions and roles:
Acceptance layer: responsible for the physical transmission of data, including PB-ADV (GAP broadcast and scanning based on BLE) and PB-GATT (point-to-point communication based on GATT protocol) two bearer modes.
Network layer: defines the network PDU format of data and is responsible for the secondary encryption and decryption of messages.
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Transport layer: responsible for the grouping and reorganization of data to ensure the integrity and reliability of data during transmission.
Access layer: defines the format of application data, controls the encryption and decryption process, and verifies the legitimacy of data.
Basic model layer and model layer: define the model and model specifications of standardized user scenario operations, including the implementation of specific application scenarios such as lighting and sensors.
5. Core advantages of SIG Mesh
Large-scale device connection: SIG Mesh supports large-scale device connection and can accommodate thousands of nodes, which is suitable for large-scale IoT application scenarios such as smart homes and smart cities.
Flexible topology: SIG Mesh supports a variety of topologies, such as star, tree, ring, etc., which can be flexibly deployed according to actual needs to improve the adaptability and scalability of the network.
Self-organization and self-repair capabilities: When nodes in the network are abnormal or disconnected, SIG Mesh can automatically adjust and repair routes to ensure reliable transmission of information.
Efficient data transmission: Through multi-hop communication and broadcast mechanisms, SIG Mesh can efficiently transmit data and reduce data transmission delays and energy consumption.
Multi-level security mechanism: SIG Mesh provides multi-level security mechanisms including message encryption, authentication, and access control to ensure the security and privacy of the communication process.
6. Summary
As a mesh network protocol based on Bluetooth technology, SIG Mesh has shown great potential in the field of Internet of Things with its high efficiency, flexibility and powerful features. By deeply understanding the working principle and architecture of SIG Mesh, we can better utilize this technology to build a more intelligent, reliable and secure Internet of Things system. In the future, with the continuous development and improvement of technology, SIG Mesh is expected to play an important role in more fields and promote the further development of the Internet of Things industry.
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