The Design And Implementation Of Constrained Application Protocol For Lightweight M2M

The technology of IoT is rapid development.While the existing industry standard can meet the communications needs of fixed broadband and smart phones,it doesn't apply for constrained nodes relying on limited batteries and constrained network.In order to solve this problem,IETF published RFC 7252,OMA proposed a highly efficient,low-power,LM2M standard,meanwhile the implement of node-coap based on Node.js is concerned by many people.The defects of design and implementation of node-coap are pointed out in the paper.To address these shortcomings,based on OMA proposed a lightweight protocol stack and constrained application protocol RFC 7252,design and implement CoAPjs framework which run in Node.js environment and written in JavaScript.The paper covers the design and implementation of message layer and request/response layer in CoAPjs,the latter provides a semantic RESTFul API interface to facilitate the development of lightweight M2M applications CoAPjs and node-coap are compared with in the functions,the software features and software performance to verify through rational hierarchical design and realize a low coupling high cohesion of the network system,can achieve higher performance.Finally,based on CoAPjs,build CoAP infrastructures:CoAP Endpoint,CoAP Proxy,CoAP-HTTP Proxy,Resource Discovery,and provides a visual interface Web-based console.