Research And Implementation Of Resource Directory System In Constrained Network

The IETF CoRE Working Group proposed coAP-based CoRE Resource Directory in the Internet draft draft-IEtF-core-ResourceDirectory released in March 2011.It is required to maintain a special resource directory node in the restricted network to integrate and manage the resources within its network scope.Therefore,as the core of resource discovery,resource catalog supports resource discovery capability in constrained networks.After more than two dozen iterations,the functionality definition in the draft resource catalog has been refined.At the same time,Californium,an open source framework,is a Java-based CoAP framework,in which various request response basic implementation of CoAP protocol,including support for CON/NON different reliability transmission modes.However,there is nothing in the framework that systematically supports resource catalog capabilities;Some of the existing studies were not able to keep pace with the draft resource catalog evolution.Therefore,it is an important task to build an effective resource catalog capability in this framework.Based on draft-IEtF-core-resource-directory-25,this paper develops software with expanded functions in Californium,an open source software framework.The specific contents are as follows:Firstly,introduce Resource Directory entities into the Californium framework,The resource directory functions described in the draft(including resource directory discovery,resource registration,resource maintenance and query,etc.)are fully and fully implemented so as to complete the function simulation of resource discovery entity RD in Californium.Secondly,multicast security has always been an important topic in the field of Internet of Things communication.After realizing the resource directory function,this paper,based on the Internet draft draft-Tiloca-coreoscot-discovery-10,analyzes the concepts of security group and group discovery,and based on the resource directory function,refers to the methods of resource discovery in the resource directory.The security group discovery function in group communication is supported and implemented.Thirdly,as evidence of the validity of principle and availability of function of the two implementations of resource catalog and group found in this paper,this paper further describes a smart campus application scenario and constructs a smart campus system consisting of three subsystems.Through the integration,statistics,query and application of campus resources in multiple campus scenarios,the function of resource catalog is reasonably and comprehensively applied and verified.It is expected that the work of this paper will have a positive impact on improving the resource directory capability of Californium and standardizing the resource directory of IETF CoRE working group.