Photonic telecommunication networks gain increasing importance in various fields extending from access to wide area networks. Due to limitations of fast all-optical switching technology, many promising concepts are based on circuit switching. In this paper, we propose a new and simple star topology using fixed wavelength assignment and a combination of wavelength and time division multiplexing. Owing to the fixed assignment, no tunable components or wavelength converters are needed in the central star element. For this system architecture, we present a performance evaluation based on a probabilistic method to calculate call blocking probabilities, which is validated by simula-. tion and compared to a rough approximation based on a simple loss system. The results allow to evaluate the trade-off between capacity increase either by additional wavelengths or additional time slots in the system.