In the vision of pervasive computing smart everyday objects communicate and cooperate to provide services and information to users. Interoperability between devices and applications not only requires common protocols but also common context management. In this paper we discuss requirements on the context management based on the Georgia Tech's Aware Home environment and the global context management perspective of the Nexus project. Our experiences with integrating the Aware Home Spatial Service into the Nexus platform show how federation concepts and a common context model can provide applications with uniform context information in different administrative and application domains.