Design And Implementation Of Message System For Internet Of Things Based On MQTT Protocol

With the development of Io T industry,the market as well as the number of device keeps growing.In addition,amounts of equipments for Io T applications have also brought new challenges.The traditional approach is that enterprise managers monitor equipment utilizing the LCD viewing data or manual recording data.However,such a way exists a series limitations,including data fragmentation,the production equipment status can not be in real-time control,the difficulty in the improvement of the quality of product,and the reduction in cost,etc.In order to solve the above problems,this paper proposes to build the messaging system of Io T.Aim at the problems of low network bandwidth,limited computing or storage resources,and poor network environment,this paper selects lightweight MQTT protocol as a message push protocol,designs and implements an Io T messaging system.The main contents of this paper are as follows:(1)Based on MQTT3.1.1 protocol,we design and implement the basic function for messags publishing and subscription.The device states of the Io T can be divided into three categories:connected,heartbeat alive and offline,which solves the problem of session information storage in distributed cluster.Offline message storage is designed based on HBase to ensure the reliability of messages.(2)For the security of system,we designed and implemented the device authentication and ACL topic authentication module.The device authentication and ACL topic authentication services are separated.The authentication services are provided in the way of HTTP API,which can provide flexible configuration of device authentication and topic authentication according to the business needs of the enterprise.We design the Kafka message bridge interface depending on the need of business to decouple messaging system from the business system.(3)We designed and implemented a decentralized messaging system cluster,and the cluster mode management which is based on Akka to facilitate the monitoring of the running state of ecah mode.Message forwarding between clusters is realized based on routing table,which ensures the accurate message forwarding between clusters.The system monitoring module is designed and implemented to provide the monitoring of the system in the form of Web page.This is convenient for the system administrator to count and monitor on the relevant business information.Finally,a detailed test for function and performance has been carried out on the system.The results show that the system can complete the basic function of message push,as well as support the business requirements of enterprise customization.The system can support 100,000 connections and 10,000 levels of concurrency,which achieves the expected purpose and has a high value of engineering application.