Evaluation of Routing Dependability in MANETs using a Topology Emulator

Enclosed CD-ROM contains source code and downloaded references. Synopsis: Performing experimental evaluation of wireless networking is prone to large differences between experiments as the non-deterministic nature of the environment may influence the results differently between tests. This fact has motivated the work described in this report, which constitutes the development and deployment of a topology emulation testbed for evaluation of routing dependability in mobile ad hoc networks. The context for routing evaluation is based on a use case where a highly dependable video conferencing application is used to provide medical assistance from a hospital to an ambulance in motion. This scenario entails ad hoc multi-hop routing from the ambulance to a gateway in the ad hoc network. The topology emulator imposes link properties of wireless links onto wired links between end-nodes, based on detailed loss and delays models incorporating properties of WLAN 802.11a with OFDM physical layer and statistical fading models for the channel. Functional and performance requirements to the topology emulation testbed have been derived and the testbed has been implemented and verified towards these requirements. A routing evaluation framework consisting of performance and dependability requirements has been defined based on the use case. Within this framework DSR and OLSR, representing the reactive and proactive families of ad hoc routing have been evaluated. From the evaluation results it is concluded that the reactive DSR is a better choice for ad hoc routing in highly dynamic ad hoc scenarios, as the end-to-end reliability of DSR surpasses that of OLSR. However, more systematic evaluation of the influencing factors from mobile environments must be performed, to further substantiate this conclusion.