The present paper presents a framework for managing quality of service in future WDM core optical networks. These networks solve the bandwidth problem but transmit complexity to the control and management layers. Part of this complexity is handled by the generalized multiprotocol label switching (GMPLS) control plane. The latter, however, cannot tackle the new challenges posed by emerging applications requiring more than bandwidth guaranteed connections. In this paper, we first study the requirements of applications and the proposed quality of service in GMPLS, and then, we try to fill up the gap between both, with a focus on the transmission delay. The resulting framework will enable the optical network to meet the exigencies of new services.