This paper presents a comparison of reservation protocols used in optical burst switches (OBS) with quality of service (QoS). In terms of performance criteria, byte loss rate, end-to-end delay and access delay are considered. A 2-state MMPP(Markov modulated Poisson process) traffic generator on a 14-node mesh network topology illustrating NSFNET is chosen as the testbed. This topology is simulated using NS2 network simulation platform. Bursts are created using a hybrid model that takes into account both timeout and maximum length methods. In edge and core nodes, there are different QoS mechanisms such as explicit tear down and priority based queuing. Simulation results have shown that JIT (just in time) algorithm is not as successful as JET (just enough time) and horizon when the network is highly loaded. However, JET algorithm produces better performance than other reservation protocols while considering QoS