Abstract
Mobile Ad Hoc Networks (MANETs) have emerged as a new paradigm in communication networks, enabling pervasive computing and ubiquitous communication environments. Their main characteristic is the mobility that nodes exhibit, with the network topology changing potentially rapidly and unpredictably. Traditional wireless networks require some form of fixed network infrastructure and centralised administration for their operation. On the contrary, MANETs are spontaneously formed, with individual nodes responsible for dynamically discovering other nodes they can communicate with. The key benefits of MANETs such as the lack of centralised administration, tether-less computing capabilities and community- based short-term network establishment are hindered by the management difficulties caused by the flexible infrastructure that underlies these benefits. There is a need for frameworks that can support the self-management of MANETs according to predefined goals or policies. We assert that such a highly dynamic environment can potentially benefit from context information that will drive its self-management, resulting in a degree of autonomy. High-level management rules expressed as policies - to achieve extensibility and flexibility - can guide the MANET configuration, triggered by context information gathered by every node and disseminated across the MANET for network-wide understanding to be established. This closed-loop adaptive management can thus lead to self-configuration, self-optimisation, and hence autonomy. This thesis addresses all critical aspects of the design, implementation and deployment of a context-aware framework to achieve self-management of MANETs. Context awareness achieved through context modelling and efficient monitoring is the foundation of this thesis. It feeds the management scheme that is built on the requirements of a MANET-oriented organisational model. Based on dynamic context information, the management scheme enforces through a programmable configuration platform changes in the MANET nodes so as to conform to the high-level management decisions. These decisions may in turn result in new context information being generated and thus new management decisions to be taken. Consequently a closed loop self-management cycle is generated, which can lead to self-optimisation, self-protection and self-healing of MANETs, subject to the appropriate network policies having been introduced into the system. The proposed context-aware framework for the self-management of MANETs is generic enough to support management changes based on any type of monitored context information, In order to validate the proposed framework, we have selected a particular application case study that relates to an adaptive routing protocol strategy. The relative mobility of the nodes in a MANET is monitored and relevant information triggers routing protocol selection and deployment. The deployed routing protocol is the appropriate one for the monitored conditions. Evaluation of this work was done using analytical modelling, simulation and also testbed experimentation. Obviously our framework is not restricted to dynamic routing strategies but allows for dynamic strategies of diverse nature to be deployed on MANETs in a generic fashion based on any type of context information. Keywords: context-awareness, context modelling, mobile ad hoc networks, network management.