In this paper, we describe the Optimized Link State Routing Protocol (OLSR) [19],[20], a proactive routing protocol for Mobile Ad-hoc NETworks (MANETs). We evaluate its performance through exhaustive simulations using the Network Simulator 2 (ns2) [1], and compare with other ad-hoc protocols, specifically the Ad-hoc On-Demand Distance Vector (AODV) [4] routing protocol and the Dynamic Source Routing (DSR) [5] protocol. We study the protocols under varying conditions (node mobility, network density) and with varying traffic (TCP, UDP, different number of connections/streams) to provide a qualitative assessment of the applicability of the protocols in different scenarios.