Mobile wide area networks promise access to information from anywhere and the ability to work in new and more productive ways. However, mobile computing environments are characterized by significant and rapid changes in supporting infrastructure. They offer one of the most diverse and challenging environments in which to build distributed systems.In this paper, We evaluate various communication styles operated in conventional distributed systems concerning about mobile computing environments. We argue that those connectionoriented paradigms are not well suited to operating in a mobile environment and instead propose a framework of extended event service on the event based communication paradigm. The QoS control of event delivery and the agent coordination based on group model are specially discussed.