Context dissemination in peer-to-peer networks

In recent years, peer-to-peer overlay networks have become a popular communication paradigm with the potential to further change communication fundamentally in the future. Overlays allow communication abstraction but suffer from one inherent problem: The overlay is unaware of the context of a service or the context of a service consumer. The concept of context-awareness emerged out of the research done within the area of ubiquitous computing. Context-aware computing is one key technology to enable services and applications in the communication environment to adapt their behaviour based on the knowledge of environmental (contextual) information, thereby enhancing the system's ability to become ever more responsive to the needs of the end-user or application domain. In this chapter we first introduce context and context architectures in general. In the remainder of the chapter we focus on the question: How can highly distributed context information be located and retrieved regarding small-scale as well as large-scale networks, addressing the topics of inter-domain management and scalability of context architectures?