A three-phase process for SLA negotiation of composite cloud services

Negotiation is used when two or more parties with conflicting goals pursue their own interests. Service trading in cloud computing is a case in which automated negotiation system (ANS) can be used to achieve high satisfaction levels for both contract parties. An ANS allows the parties negotiate automatically on some parameters that are important for them. Multiple services are combined together to provide a composite service that delivers a value-added service to consumers. With the increasing tendency to use composite cloud services, there is a need for designing ANSs capable of fulfilling requirements of consumers of these services. Unlike existing ANSs which support negotiation of single service, our proposed ANS supports negotiation of composite service. This work also proposes a novel negotiation strategy to enhance satisfaction of both trading parties. Some simulations were carried out to evaluate the performance of proposed negotiation strategy in terms of negotiating agents' utility and negotiation speed. Analysis of the results of simulations shows that our recommended strategy provides more performance than the others.