SLA composition in service networks: a tool for representing relationships between SLAs and contracts

Actual trends in IT management are more and more shifting towards services and their management. Typically, enterprises depend on services provided by third parties to realize their own service offers. However, the more services are composed, the higher grows the number of inter-and intra-organizational issues in service networks. Business Process Outsourcing (BPO) and Cloud Computing paradigms best represent such a complex scenario and require proper service governance across service providers and consumers. This can be achieved by revolving to Service Level Agreements (SLAs), in order to effectively manage contracts between parties as well as the corresponding obligations and guarantees over specific time spans. However, SLAs are mainly used as automated processes assisting users in monitoring and scheduling resources rather than end-user documents. SLAs are also seen as static documents in IT marketplaces, thus hindering their effective processing. In addition, when services are composed into higher-level ones, the contracts they are agreed upon and their SLAs should be composed accordingly. For such reasons, this research work has a two-fold purpose. Firstly, it aims at a better modeling of contracts and SLA composition. Contract templates as well as composition topologies and rules are introduced. Secondly, it proposes a tool for designing and visualizing service contracts composition and for simplifying data handling in contracts. The proposed tool exploits a directed tree graph paradigm in addition with an XML-based notation.