Optical Burst Switching (OBS) is one of the suggested that switching paradigms be used in Internet-Protocol over Wavelength Division Multiplexing (IP over WDM) networks along with Optical Circuit Switching (OCS) and Optical Packet Switching (OPS). It combines the advantages of both OCS and OPS and avoids their limitations. Hence, OBS technology is a promising solution for the backbone of next-generation Internet. Since OBS networks are anticipated to be the core for variety of applications, an appropriate Quality of Service (QoS) algorithm is essential to handle the task. One of the major concerns in OBS networks is contention resolution, especially in the case of composite burst assembly. Composite burst assembly scheme suggests the assembling packets of different classes of services into a data burst. In this study, composite burst assembly with a different segmentation size scheme is deployed. Hence, at the ingress (edge) node of OBS network aggregates the arrival low-priority packets into small segments in the data burst while the higher-priority packets are placed into large segments in the data burst. At the core (intermediate) nodes of OBS network, when contention occurs, dropping small segments of burst is deployed. However, the mechanisms are evaluated in terms data loss, and it is observed that the high-priority data have significantly lower losses, when compared to the low-priority data. In addition, based on simulation results, it is shown that an adequate QoS level could be achieved with a simple and easy modification to the OBS with burst segmentation strategy.