  Service-Oriented Computing (SOC) enables the composition of loosely coupled
service agents provided with varying Quality of Service (QoS) levels,
effectively forming a multiagent system (MAS). Selecting a (near-)optimal set
of services for a composition in terms of QoS is crucial when many functionally
equivalent services are available. As the number of distributed services,
especially in the cloud, is rising rapidly, the impact of the network on the
QoS keeps increasing. Despite this and opposed to most MAS approaches, current
service approaches depend on a centralized architecture which cannot adapt to
the network. Thus, we propose a scalable distributed architecture composed of a
flexible number of distributed control nodes. Our architecture requires no
changes to existing services and adapts from a centralized to a completely
distributed realization by adding control nodes as needed. Also, we propose an
extended QoS aggregation algorithm that allows to accurately estimate network
QoS. Finally, we evaluate the benefits and optimality of our architecture in a
distributed environment.
