This article provides a technical overview of mobile ad hoc networks and describes their long-term potential. It covers current research, and describes major technical challenges, including networking, real-time services, and software. It shows that by their very nature, mobile ad hoc networks can bring a paradigm shift in the way networks are organized and operated, and can even lead to a fundamental change in the relationships between information technology and societal organization. As an illustration of these concepts, the article also contains an overall description of our long-term research project, called terminodes.

No abstract

Modern networks provide a QoS (quality of service) model to go beyond best-effort services, but current QoS models are oriented towards low-level network parameters (e.g., bandwidth, latency, jitter). Application developers, on the other hand, are interested in quality models that are meaningful to the end-user and therefore struggle to bridge the gap between network and application QoS models. Examples of application quality models are response time, predictability, or a budget (for transmission costs). Applications that can deal with changes in the network environment are called network-aware. A network-aware application attempts to adjust its resource demands in response to network performance variations. This paper presents a framework-based approach to the construction of networkaware programs. At the core of the framework is a feedback loop that controls the adjustment of the application to network properties. The framework provides the skeleton to address two fundamental challenges for the construction of network-aware applications: (i) how to find out about dynamic changes in network service quality and (ii) how to map applicationcentric quality measures (e.g., predictability) to network-centric quality measures (e.g., QoS models that focus on bandwidth or latency). Our preliminary experience with a prototype network-aware image retrieval system demonstrates the feasibility of our approach. The prototype illustrates that there is more to network-awareness than just taking network resources and protocols into account and raises questions that need to be addressed (from a software engineering point of view) to make a general approach to network-aware applications useful.

Today, any large object-oriented software system is built using frameworks. Yet, designing frameworks and defining their interaction with clients remains a difficult task. A primary reason is that today's dominant modeling concept, the class, is not well suited to describe the complexity of object collaborations as it emerges in framework design and integration. We use role modeling to overcome the problems and limitations of class-based modeling. Using role models, the design of a framework and its use by clients can be described succinctly and with much better separation of concerns than with classes. Using role objects, frameworks can be integrated into use-contexts that have not been foreseen by their original designers.