Improvement And Application Of Network Chord Protocol

Peer-to-Peer network can organize resources in a distributed way, and is not restricted by central server. DHT technology is now the mainstream of peer-to-peer network's lookup arithmetic. Being a typical peer-to-peer system arithmetic, Chord protocol solves the problem of how to locate keys, how to let new nodes join in the system, and how to recover from the failure of exiting nodes. The core function of Chord is using consistent hash function to map resources and nodes to a one-dimension circle, then all the route operations are carried out in this circle. This paper firstly analyses Chord protocol deeply , and then proposes several betterments of Chord protocol.Firstly, this paper introduces correlative knowledge and research actuality of peer-to-peer network , DHT arithmetic, and especially introduces Chord protocol. secondly, this paper proposes grouping Chord with group table, and illuminates how to handle lookup, node join, node leaving, node failure particularly, then proves conclusions as follows: grouping Chord can reduce lookup hop, lighten infection of node change and network burden in some conditions. Thirdly, through analysing ancient style of route table building based on PNS, we proposes a method of combining node exchange and PNS to build route table. So we can reduce the complexity of route table update. Lastly, this paper proposes an adjusting method of grouping based on geography difference. Through adjusting long delay nodes between groups, we can reduce the whole lookup delay.Besides, this paper carrys out some simulate experiments and analyses the result of route hops, messages number of update route table, and lookup delay to validate the validity of the methods proposed above. At last, we apply some of methods above to upgrade program of host vulnerability patch to quicken the speed of upgrade process, and enhance the host's ability of resisting danger.