After several real experiments in which results exposed short lifetime and connectivity problems, we have studied role-based network organization methods. Node location within the network is very important because packet forwarding rate directly depends on this factor. Task assigned to each node is also very important because the collaboration between nodes is indispensable for the correct network operation. To demonstrate the importance of node location in the network, we have performed several experiments with different topologies and results have exposed that a Base Station located in the center of the area to monitor and surrounded by many nodes is the best solution in terms of energy consumption and load balancing. © 2008 ACM.