A state management and persistency architecture for peer-to-peer massively multi-user virtual environments

[摘要] ENGLISH ABSTRACT: Recently, there has been significant research focus on Peer-to-Peer (P2P) MassivelyMulti-user Virtual Environments (MMVEs). A number of architectures have beenpresented in the literature to implement the P2P approach. One aspect that hasnot received sufficient attention in these architectures is state management andstate persistency in P2P MMVEs. This work presents and simulates a novel statemanagement and persistency architecture, called Pithos.In order to design the architecture, an investigation is performed into state consistencyarchitectures, into which the state management and persistency architectureshould fit. A novel generic state consistency model is proposed that encapsulated allstate consistency models reviewed. The requirements for state management and persistencyarchitectures, identified during the review of state consistency models, areused to review state management and persistency architectures currently receivingresearch attention.Identifying some deficiencies present in current designs, such as lack of fairness,responsiveness and scalability, a novel state management and persistency architecture,called Pithos, is designed. Pithos is a reliable, responsive, secure, fair andscalable distributed storage system, ideally suited to P2P MMVEs. Pithos is implementedin Oversim, which runs on the Omnet++ network simulator. An evaluationof Pithos is performed to verify that it satisfies the identified requirements.It is found that the reliability of Pithos depends heavily on object lifetimes. If anobject lives longer on average, retrieval requests are more reliable. An investigationis performed into the factors influencing object lifetime. A novel Markov chain modelis proposed which allows for the prediction of objects lifetimes in any finite sizednetwork, for a given amount of redundancy, node lifetime characteristics and objectrepair rate.

[发布机构] Stellenbosch University