Negotiation towards Service Level Agreements: A Life Cycle Based Approach

Service Based Systems (SBSs) are composed of loosely coupled services. Different stakeholders in these systems, e.g. service providers, service consumers, and business decision makers, have different types of concerns which may be dissimilar or inconsistent. Service Level Agreements (SLAs) play a major role in ensuring the quality of SBSs. They stipulate the availability, reliability, and quality levels required for an effective interaction between service providers and consumers. It has been noticed that because of having conflicting priorities and concerns, conflicts arise between service providers and service consumers while negotiating over the functionality of potential services. Since these stakeholders are involved with different phases the life cycle, it is really important to take into consideration these life cycle phases for proposing any kind of SLA negotiation methodology. In this research, we propose a stakeholder negotiation strategy for Service Level Agreements, which is based on prioritizing stakeholder concerns based on their frequency at each phase of the SBS development life cycle. We make use of a Collaxa BPEL Orchestration Server Loan service example to demonstrate the applicability of the proposed approach. In addition, we simulate the negotiation priority values to predict their potential impact on the cost of the SLA negotiation.