Mobile Ad hoc Networks (MANET) are self-configured and infrastructure less networks with autonomous mobile nodes. Due to the high flexibility, these kind of networks are heavily used in rescue operations, military missions etc. Many routing protocols for this kind of networks exist. This article presents a comparative and quantitative performance study of DSDV, AODV and DSR routing protocols using different simulation models in NS2. Performance metrics like PDR, E2E Delay and Throughput are analyzed under varying network, traffic and mobility parameters like number of nodes, traffic flows, mobility speed and pause time. Results show that AODV outperforms DSDV and DSR in all the performance metrics. DSDV performs better than DSR in terms of PDR and E2E delay. DSR gives 20-30 higher Throughput than DSDV. Performance metrics are highly influenced by network topology parameters like number of nodes and number of traffic flow connections. Mobility parameters like speed and pause time have slight impact on performance.