Multilayer QoS in integrated IP over Optical Networks

The number of IP based services concurrently transmitted over the Internet is incessantly increasing, causing IP layer QoS control mechanisms to be unable to satisfy the service level agreements (SLAs). Besides providing a huge amount of transmission capacity, optical networks should also cooperate with the IP layer in differentiating the provided grade of QoS according to the different traffic types requirements. The cooperation is facilitated by the development of generalized multi protocol label switching (GMPLS) in both optical and IP networking that is bringing the two domains close together. The result is an integrated network using a unique traffic engineering database (TED) and where a node has complete knowledge of both physical and logical topology. This paper proposes a multilayer QoS framework for such networks. The scheme differentiates traffic also when being transmitted over the optical layer. Three classes of service (CoSs) are defined and each one is served following a different routing policy, in order to provide different CoS with different grades of QoS. The simulation results show that without a significant penalization in terms of blocking probability, the QoS sensitive traffic undergoes a shorter delay and lower values of optical-electronic-optical (O-E-O) signal conversion.