The rise of communicating devices has led to more and more machine to machine applications. In this context devices can be modeled using service-oriented computing. Furthermore service-oriented approach paradigms support the dynamic nature inherent in this kind of applications. However even though devices and their services can cooperate in the same application, they are likely to belong to independent organizations. As a consequence each part of the application need guarantees on the service availabilities, and this can be achieved through service level agreements.