The Research And Implementation Of Cloudifcation Based Coap Reliable Group Communication

Internet of Things is a network technology based on Internet expansion,so as to realize the exchange of information of M2M.Due to the limited resources of devices in the Internet of Things,the IETF CoRE working group proposed a limited application protocol(CoAP)based on the REST architecture.However,in the limited network environment,there are many nodes and their regional associations The correlation between sexuality and function are large,and group communication has become an important communication method in the Internet of Things.The Open Mobile Alliance(OMA)defines a lightweight machine-to-machine(LWM2M)communications protocol stack that applies CoAP to large-scale electrical switching control applications.Applications defined by OMA require reliable communications capabilities,but the IETF CoRE Working Group only defines standards for CoAP unreliable group communications.With the technology development trend of combining Internet of Things with cloud computing,it becomes an important issue to implement CoAP group communication/reliable group communication capabilities on a cloud computing platform.In order to meet the actual needs of the Internet of Things scenario,the reliability of the CoAP group communication needs to be provided.The cloud computing excellent computing power and dynamic scalable virtual network resources,combined with the Internet of things,through the cloud computing can be achieved on a large number of nodes in the Internet of Things real-time dynamic management and intelligent analysis,in theory,can Ensure reliable transmission of CoAP group communication.In the previous exploration of the solution,there was no mention of a solution that combined cloud computing with the Internet of Things.Therefore,based on the cloud computing model,this paper presents a design scheme of CoAP reliable group communication based on proxy server on the cloud platform.Using cloud proxy to cache forwarding and control unicast and multicast to achieve the completion of the cloud platform In order to control the nodes under the restricted network,the method of intelligent judgment and retransmission is realized,and the control mechanism of sleeping nodes is added.Due to the complexity of IoT group communication,we propose an entity-based group communication management mechanism,which is controlled and forwarded by the cloud agent.Finally,the design of reliable group communication is realized.In addition,for the problem of network congestion caused by retransmission,this paper adds network congestion control mechanism to the scheme based on cloud proxy to improve the reliability and communication efficiency of group communication.Finally,the CoAP reliable group communication on the cloud was implemented.In addition to verifying the integrity of its functions,the paper also proposed a reliable group communication scheme based on cloud proxy and the existing agent-based and totally dependent unicast Implementation of reliable group communication protocol were tested,and the experimental results of the three were compared.The experimental results finally show that CoAP reliable group communication based on cloud platform agent is feasible and more reliable than other implementations.