From an Ontology of Service Contracts to Contract Modeling in Enterprise Architecture

Service contracts bind parties legally, regulating their behavior in the scope of a (business) service relationship. Given that there are legal consequences attached to service contracts, understanding the elements of a contract is key to managing services in an enterprise. After all, provisions in a service contract establish obligations and rights for service providers and customers that must be respected in service delivery. The importance of service contracts to service provisioning in an enterprise has motivated us to investigate their representation in enterprise models. We have observed that approaches fall into two extremes of a spectrum. Some approaches, such as ArchiMate, offer an opaque "contract" construct, not revealing the rights and obligations in the scope of the governed service relationship. Other approaches, under the umbrella term "contract languages", are devoted exactly to the formal representation of the contents of contracts. Despite the applications of contract languages, they operate at a level of detail that does not match that of enterprise architecture models. In this paper, we explore the gap between these two extremes. We address the representation of service contract elements with a systematic approach: we first propose a well-founded service contract ontology, and then extend the ArchiMate language to reflect the elements of the service contract ontology. The applicability of the proposed extension is assessed in the representation of a real-world cloud service contract.