Behavior of ad hoc routing protocols in metropolitan environments

The current implementation of propagation models for the network simulator ns-2 only allows simulations within flat environments. Nodes are always within line of sight and the distance between one and another determines their connectivity. Our extensions permit simulations within urban and non-flat environments. This gives new insights into the behavior of routing algorithms. The simulation environment has great impact on the performance of ad hoc routing algorithms. Results show that packet loss and routing overhead are dramatically increased. Further, they advise the assumption that AODV always outperforms DSR. However, both have great shortcomings concerning networks with fast moving or numerous nodes. Results suggest the necessity for new routing algorithms or imply a paradigm shift for the application of ad hoc networks.