There is a global trend towards service-orientation,
both for organizing business interactions but also in modern IT
architectures. At the business-level, service industries are becom-
ing the dominating sector in which solutions are flexibly com-
posed out of networked services. At the IT level, the paradigms
of Service-Oriented Architecture and Cloud Computing realize
service-orientation for both software and infrastructure services.
Again, flexible composition across different layers is a major
advantage of this paradigm. Service Level Agreements (SLA)
are a common approach for specifying the exact conditions under
which services are to be delivered and, thus, are a prerequisite
for supporting the flexible trading of services. However, typical
SLAs are just specified at a single layer and do not allow service
providers to manage their service stack accordingly. They have
no insight on how SLAs at one layer translate to metrics or
parameters at the various lower layers of the service stack.
In this paper, we present a reference architecture for a multi-
level SLA management framework. We discuss the fundamental
concepts and detail the main architectural components and
interfaces. Furthermore, we show how the framework can be
flexibly used for different industrial scenarios.