The paradigm of service-oriented architectures (SOA) is by now accepted for application integration and in widespread use. As an underlying key-technology of cloud computing and because of unresolved issues during operation and maintenance it remains a hot topic. SOA encapsulates business functionality in services, combining aspects from both the business and infrastructure level. The reuse of services results in hidden chains of dependencies that affect governance and optimization of service-based systems. To guarantee the cost-effective availability of the whole service-based application landscape, the real criticality of each dependency has to be determined for IT Service Management (ITSM) to act accordingly. We propose the FIT-metric as a tool to characterize the stability of existing service configurations based on three components: functionality, integration and traffic. In this paper we describe the design of FIT and apply it to configurations taken from a production-strength SOA-landscape. A prototype of FIT is currently being implemented at Deutsche Post MAIL.

Today there is no best practise method available to effectively estimate the maintenance costs of historically grown large-scale software landscapes. Most cost estimation models are either not generalizable due to highly specialized scenarios or too abstract to be implemented in practice. In this paper we introduce a multi-level approach to create transparency, estimate costs realistically based on current spending and establish a method for sustainable cost-control. At the heart of our approach is the deduction of meaningful indicators for estimating current and future maintenance efforts. We present the first version of a statistical cost estimation model being implemented at Deutsche Post MAIL as a baseline for contract negotiations with providers.