Mobile Codes Localization in Ad hoc Networks: a Comparative Study of Centralized and Distributed Approaches

10.5121/ijcnc.2010.2213 164
        

              Youcef Zafoune1, Aicha Mokhtari1 and Rushed kanawati2 1Department of Computer Science, USTHB University, Algiers, Algeria yzafoune@usthb.dz , amokhtari@usthb.dz 2 Institute Galilée, Paris13 University, Paris, French
rushed.kanawati@lipn.univ-paris13.fr ABSTRACT This paper presents a new approach in the management of mobile ad hoc networks. Our alternative, based on mobile agent technology, allows the design of mobile centralized server in ad hoc network, where it is not obvious to think about a centralized management, due to the absence of any administration or fixed infrastructure in these networks. The aim of this centralized approach is to provide permanent availability of services in ad hoc networks which are characterized by a distributed management. In order to evaluate the performance of the proposed approach, we apply it to solve the problem of mobile code localization in ad hoc networks. A comparative study, based upon a simulation, of centralized and distributed localization protocols in terms of messages number exchanged and response time shows that the centralized approach in a distributed form is more interesting than a totally centralized approach. KEYWORDS Agent, Ad hoc, Centralized, Distributed, Localization, Mobile

1. INTRODUCTION Mobile ad hoc networks is an emerging technology that has gained a lot of interest due to the wide spreading of mobile and wireless devices (i.e. personal assistance, net-books, embedded computers, etc.). An ad hoc network can be defined as a collection of mobile entities interconnected by a wireless technology, forming a temporary network without the help of any administration or any fixed support. This class, which tries to extend the mobility notions to all the composites of the environment, is characterized by a dynamic topology, limited bandwidth and energy power. The absence of the fixed infrastructure obliges the mobile units to behave as routers which participate in the discovery and the maintenance of the paths for the network hosts. These mobile hosts themselves which form, in an ad hoc manner, a way of global architecture which can be used as an infrastructure of the network. Consequently, any management in these networks is a distributed type. The distributed applications call most often at all nodes in the network, resulting in a response time and a flood of messages quite important. Is it possible to envisage a centralized management as an alternative? That is the aim of our research in this paper. Our alternative consists in designing mobile centralized server in ad hoc network. The aim of this centralized approach is to provide permanent availability of services in ad hoc networks. Our proposed approach for ad hoc networks where it is not obvious to think about a centralized management is based on mobile agent technology. The mobile code technology, issued from the domain of artificial intelligence under the name of mobile agent, is now growing fast. This is promising in many fields of application, especially in the field of nomadic computer science and in the distributed applications in large scale networks (such as information retrieval and
             
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165 electronic commerce in the web). A mobile agent is a software agent that has the ability to move from one hosting node to another without interpreting its execution. The challenge with using the mobile agent technology is to endow the mobile server with the capacity to select a hosting node to enhance the obtained service. In order to evaluate the performance of the proposed approach, we apply it to solve the problem of mobile code localization in ad hoc networks. The localization mechanism has become a major component of future services with the proliferation of communicating objects. Many localization methods of mobile objects in different kind of networks have emerged. In our study, we are interested in the problem of the mobile code localization in mobile ad hoc networks. While in the network with fixed stations, the mechanisms of localization of mobile code are classic, it is not the same for mobile ad hoc networks characterized by a dynamic network topology. In the second section of this paper, we present the problematic of mobile object localization. In the third section, we describe our proposed mobile code’s localization protocols in the ad hoc network. Then, a comparative study of centralized and distributed approaches, based upon a simulation, is presented in the fourth section. Section five presents an improvement of th

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