Research On Caching Algorithm In Publish/Subscribe Network

Publish/Subscribe Network is a flexible communication model whichsupport communication using the content of the message rather than thenetwork address, so it can meet the need of data transmission in large scale.In traditional Publish/Subscribe Network, messages are not stored in thenetwork and subscribers can only receive the messages published whilethey are online. However, in some dynamic scenes where the users joinand leave the system dynamically, a new user might be interested in themessages published in the past.This paper proposes a distributed message persistence algorithm tosupport message persistence and message retrieval in Publish/SubscribeNetwork, while maintaining the loosely coupled and asynchronouscommunication of the system. By comparing with the other two messagepersistence algorithms, the proposed caching algorithm performs well inpersistence capacity, overhead of history retrieval and scalability.This paper also proposes a message placement algorithm inPublish/Subscribe Network. The proposed algorithm places the messagesin Publish/Subscribe Network according to the priori knowledge ofpossible users, so as to minimize the user response delay during messageretrieval. By comparing with the other two message placement algorithms,the proposed caching algorithm performs well in user response delay.Finally, this paper implements a new Publish Subscribe system, whichcan store the published messages in the network and provide the users withsubscription to the historical messages.