A Hybrid Model for Ranking Cloud Services

In this paper we analyse the typical inter-cloud scenario, with particular reference to the negotiation of a CSA (Cloud Service Agreement). Thereafter, the roles of the main players - customers, providers, brokers, and auditors -- are taken into account along with reciprocal trust relationships. On this basis, we propose a hybrid model for ranking cloud services. By means of the proposed model we take into account QoS measurements performed by independent Brokers plus certifications made by Auditors. Furthermore, in addition to objective QoS measures, the described model represents an attempt to integrate a reputation system which involves the community of Cloud users in a typical inter-cloud scenario. Indeed, they are supposed to interact with brokers in order to release feedbacks based on their direct experience, and send opinion (recommendations) to potential Cloud customers.