This paper presents an architectural overview of a robot-based visitor information system in a university building. Two mobile robots serve as mobile information terminals providing information about the employees, labs, meeting rooms, and offices in the building and are able to guide the visitors to these points of interest. The paper focuses on the different software components needed to meet the requirements of the multi-story office building. Furthermore, the integration of a multi-hypotheses person tracker is outlined, which helps the robots to interact with the people in their near surrounding. Besides first observations on interaction, the further development is outlined as well.