We analyze the performance of ad hoc pro-active routing protocol OLSR. In particular we focuse on the multipoint relay concept which is the most salient feature of this protocol and which brings the most significant breakthrough in performance. We will anlyse the performances in two radio network models: the random graph model and the unit graph. The random graph is more suitable for indoor networks, and the unit graph is more suitable for outdoor networks. We compare the performance of OLSR with the performance of link state protocols using full flooding, such as OSPF.