Cloud Computing Oriented SLA-based Dynamic And Trusted Negotiation Mechanism

With the coming of information era,cloud computing rapidly develops with forming a cloud service market.In cloud computing,Service Level Agreement(SLA)is an important means to measure and ensure the quality of service.SLA has become an important research topic of cloud computing.Due to the number of users in the cloud environment goes enormous increase,the SLA that depended on artificial negotiation can't meet the needs of cloud computing environment.Therefore,automatic SLA negotiation that introduced the Agent technology has been becoming the current hot spots of research content.Previous studies of SLA negotiation mostly ignored the dynamic characteristics of cloud computing environments,which assumed the negotiation environment was static.They can't solve the practical problems in the cloud environment.At the same time,they ignore the unreliable factors in the cloud environment,which can lead to no credibility of the negotiation results.Trust is an important factor of market competition.It will produce a great impact on the entire cloud market.Existing SLA negotiation mechanisms generally negotiate by fixed strategy in mutual trust environment,whose adaptability and flexibility have great limitations,and they also can't meet the demands of the open and dynamic cloud computing environment.Aiming at the shortcomings of the existing research,this paper presents a dynamic negotiation model based on supply-demand relationship under cloud computing environment.The model can dynamically adjust the negotiation strategy according to the change of cloud market supply-demand relationship as well as negotiation opponents' credibility,in order to implement a flexible and efficient cloud services SLA negotiation.Firstly,establishing the model for forecasting the market supply-demand relationship,and introducing a credibility factor with time attenuated into it.Then on this basis,construct a dynamic negotiation mechanism based on market supply-demand relationship,called DRM(Dynamic supply-Request negotiation Model).In addition,in order to let the negotiation mechanism be more aligned with the demand of multiple issues in cloud market transactions.On the basis of the DRM dynamic negotiation model,this paper designs dynamic tradeoff strategy based on parallel proposal.This strategy called DPTS in paper,which combines dynamicconcession mechanism and parallel-offer tradeoff mechanism.The DPTS implement efficient multiple issues automatic negotiation of cloud service.Finally,to verify the effectiveness of DRM negotiation model and the efficiency of DPTS negotiation strategy,we simulate negotiation in the CloudSim platform.Experiments show that,the proposed dynamic negotiation model based supplydemand relationship can achieve better performance in the different cloud environment,reflected the effectiveness of the proposed model.At the same time,compared with other typical negotiation strategy,DPTS negotiation strategy gives a better performance in negotiation round number and success rate of negotiation,which verify the feasibility and efficiency of this strategy.