Quality of service in mobile and wireless networks: the need for proactive and adaptive applications

Although there are already many fixed networked computers around the world, we will see several orders of magnitude more wireless and mobile devices connected to the Internet. Each car, truck, aircraft, but also many people will carry a plethora of different devices for communication. However, all mobile and wireless systems have in common that the quality of their connectivity may change rapidly over time. Still, users want to get the best quality possible or the quality they pay for respectively. We describe the implementation of adaptive and proactive applications that are supported by our architecture. The user can express his or her preference by simply clicking on a Q(uality)-button; the process of adaptation is performed without any user interaction. Feedback loops connecting applications, operating system, and network system realize the adaptation. We show how our architecture supports traditional adaptive applications and demonstrate the benefits of proactive applications in wireless and mobile environments.