Fixed infrastructured networks naturally support centralized approaches for group management and information provisioning. Contrary to infrastructured networks, in multi-hop ad-hoc networks each node acts as a router as well as sender and receiver. Some applications, however, requires hierarchical arrangements that—for practical reasons—has to be done locally and selforganized. An additional challenge is to deal with mobility that causes permanent network partitioning and re-organizations. Technically, these problems can be tackled by providing additional uplinks to a backbone network, which can be used to access resources in the Internet as well as to inter-link multiple ad-hoc network partitions, creating a hybrid wireless network. In this paper, we present a prototypically implemented hybrid wireless network system optimized for multimedia content distribution. To efficiently manage the ad-hoc communicating devices a weighted clustering algorithm is introduced. The proposed localized algorithm deals with mobility, but does not require geographical information or distances. Categories and Subject Descriptors C.2.1 [Network Architecture and Design]: Distributed networks, network communications, network topology, wireless

Mobile Ad hoc NETworks (MANETs) are dynamic networks populated by mobile stations. Stations in MANETs are usually laptops, PDAs or mobile phones. These devices feature Bluetooth and/or IEEE 802.11 (WiFi) network interfaces and communicate in a decentralized manner. Mobility is a key feature of MANETs. Because of their high cost and their lack of flexibility of such networks, experimentation is mostly achievable through simulation. Numerous tools exist for MANETs simulation, including ns-2 and GloMoSim which are the two most popular ones. This paper provides a State of the Art of MANETs simulators and associated simulation techniques. First it gives an overview of the domain. Then it provides a map of the main characteristics that MANETs simulation tools should feature and the current support of these. Finally, a description for each simulator is provided, including an explanation of what make them appealing solutions. Key words: Mobile ad hoc networks, MANETs, simulation.

This work presents a communication pattern for high mobile ad hoc networks. En-passant communication uses the short interaction period of passing devices to efficiently synchronize the information of each device. This is achieved by creating peer-to-peer overlays of interest domains. Missing information is determined by exchanging profiles first. As example application UbiQuiz is presented, a mobile quiz application. It exchanges

This work presents a middleware architecture for distributed applications communicating solely over a mobile multihop ad-hoc network. The design of the platform is based on the marketplace pattern where communication among negotiating components of an application concentrates on bounded geographical areas, called marketplaces. The marketplace pattern allows to develop resource saving and selforganizing applications needing no additional administrative overhead and coping well with permanent network partitions.

Abstract. Simulations, emulations, and test deployments play a central role in design and development of ad hoc network protocols and software. Among these three methods, emulations have gained considerable popularity. This is partly because emulations address efficiency-accuracy trade-off of simulations by incorporating real hardware or software into the synthetic environment in a controlled manner. Although generally treated as a special case of simulations, emulation experimentation have its own problems and pitfalls. These problems do not typically show up in simulation studies, since they stem from presence of real hardware or software in the experiment. In this paper, the sketch of an emulation integrated development lifecycle is presented for establishing the boundaries of emulation experiments, and the problems specific to emulations are identified and discussed. 1

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The goal of the GecGo middleware is to provide all the services required by self-organizing distributed applications running on multihop ad-hoc networks. Because of the frequent as well as unreliable and anonymous communication between accidental neighbors observed in these networks, applications have to adapt continuously to changes in the mobile environment and the GecGo middleware offers the required tight coupling. Additionally, GecGo addresses specifically the issue of en passant communication, where moving neighbor devices may interact only for short periods of time. In this paper, the architecture and basic concepts of the GecGo middleware are discussed and a prototype implementation of GecGo using the Microsoft Windows CE 4.2 .NET operating system for mobile devices and the .NET Compact Framework is presented. The paper also addresses issues on application programming and example application prototypes for these mobile networks.

this paper, the sketch of an emulation integrated development lifecycle is presented for establishing the boundaries of emulation experiments, and the problems specific to emulations are identified and discussed

1.1 Definitions from the literature.......................... 28