Optical Label Switching (OLS) is a promising technology that can provide ressource provisioning and quality of service (QoS) support. In OLS networks, admission control can be implemented using control protocols that handle signaling tasks, resource provision, and QoS requirements satisfaction. In this paper, we use a core node architecture to build a call admission control protocol using dynamic QoS performance parameters. We also develop a theoretical model for evaluating the performance of the proposed protocol by means of a conservation law and a queuing network model. Finally, we verify the performance of our approach using simulation analysis.