Research And Implementation On ONS Resolving System Of Iot Based On Multistage Chord

The information in IOT(the Internet of things) have characteristics of Dynamicchange、large amount of data、high requirement of security、scattered memory addressand so on.There are two mechanisms which are mechanism based DNS(domain nameresolution) and mechanism based structured distributed P2P technology in ONS(Object Name Service).The mechanism of DNS-ONS adopts centralized C/S modeand need to change the EPC code into domain name before resolving identify,whichcan lead to the problems of bottlenecks in root server performance、 poorextensibility、high overhead and delay in querying.And the querying efficiency is notsignificant in P2P-ONS due to the heterogeneity of nodes、not matching of physicaladdress and logic address,and its stable performance is not ideal in dynamicenvironment of IOT.This paper studies deeply on the existing mechanism of DNS-ONS andstructured P2P-ONS,and proposed an ONS system using multistage Chord on thebasis of analyzing the advantages and disadvantages of them.Taking the two levelsChord-ONS(TLChord-ONS) system for example,this system has the followingadvantages: the system uses EPCIS service nodes instead of ONS which providingquerying service and EPCIS information servers,which qureying informationswithout changing identifies into domain names, so the query overhead is reduced;thenodes in TLChord-ONS system are divided into super nodes and ordinary nodesaccording to the management field of EPC coding system,which solving effectivelythe problems of heterogeneity and not high matching of logical addresses andphysical addresses in structured P2P network, and improving the query efficiency;arouting strategy is proposed in TLChord-ONS system,that is the upper network usingthe improved two-way Chord based node distance and the underlying network usingindex cached mechanism,which making full use of node heterogeneity and improvingthe searching performance.At last,this paper simulates and analyzes the routing performance of TLChord-ONS network and structured Chord-ONS network through PeerSim simulator.Theresult shows that with the expansion of network and increasing of number of nodes, the performance of TLChord routing mechanism is better than Chord routingmechanism in these respects of querying hops、querying latency and stability.So theTLChord routing mechanism is more suitable for the environment of IOT.