Optical Quality of Service (QoS) for different classes of service in dynamic transparent optical networks is here addressed through Four Wave Mixing (FWM)-aware algorithms. The traffic classes differ in quality attributes, namely, transmission Bit Error Rate (BER) and blocking probability. The algorithms are tested on two mesh topologies against offered traffic, for different numbers of wavelengths per link. Results suggest that in order to simultaneously maintain Optical Service Level Agreement (OSLA) and efficient utilization of the resources, there must be some form of Connection Admission Control (CAC) mechanisms able to provide class isolation. This paper shows that this can be done either explicity or through a simple mechanism that is able to reduce lightpath non-linear interaction and favour the admission of high-priority traffic. A scalable and efficient mechanism based on shortest route, congestion avoidance and first fit wavelength assignment is suggested as a practical solution to QoS-Aware multiservice optical network. © 2005 IEEE.2005 431438Kaheel, A., Khattab, T., Mohamed, A., Alnuweiri, H., Quality-of-service mechanisms in IP-over-WDM networks (2002) Communications Magazine, 40, pp. 38-43. , DecBraden, R., Integrated services in the internet architecture: An overview (1994) RFC, 1633. , JunBlake, S., An architecture for differentiated services (1998) RFC, 2475. , DecAhmed, C.B., Boudriga, N., Obaidat, M.S., Supporting adaptive QoS for multiple classes of service in DWDM networks (2001) Proc. IEEE Int. Conf. on Parallel Processing Workshops, pp. 283-288. , SeptRamaswami, R., Sivaraja, K.N., (2002) Optical Networks: A Practical Perspective, 2nd Ed., , San Francisco, CA: Morgan Kaufmann PublishersQiao, C., Yoo, M., Optical Burst Switching (OBS) - A new paradigm for an optical internet (1999) Journal of High Speed Networks, 8, pp. 69-84. , JanXu, L., Perros, H.G., Rouskas, G., Techniques for optical packet switching and optical burst switching (2001) Communications Magazine, 39, pp. 136-142. , JanGiroux, N., Ganti, S., (1999) Quality of Service in ATM Networks: State-of-the-art Traffic Management, , New Jersey, Prentice-HallFredette, A., Lang, J.P., Link Management Protocol (LMP) for Dense Wavelength Division Multiplexing (DWDM) optical line systems (2003) Internet Draft (Work in Progress), Draft-ietf-ccamp-lmp-wdm-03.txt, , Dec(2000) Characteristics of Transport Equipment - Description Methodology and Generic Functionality, , ITU-T Rec. G.806, OctFonseca, I.E., Ribeiro, M.R.N., Almeida Jr., R.C., Waldman, H., Preserving global optical QoS in FWM impaired dynamic networks (2004) Electronics Letters, 40, pp. 191-192. , FebLevandovsky, D., Wavelength routing based on physical impairments (2001) Proc. IEEE OFC'01, pp. TuG71-TuG73Ramamurthy, B., Datta, D., Feng, H., Heritage, J.P., Mukherjee, B., Impact of transmission impairments on the teletraffic performance of wavelength-routed optical networks (1999) J. Ligthwave Technology, 17, pp. 1713-1723. , OctAli, M., Tancevski, L., Impact of polarization-mode dispersion on the design of wavelength-routed networks (2002) Photonics Technology Letters, 14, pp. 720-722. , MaySaradhi, C.V., Gurusamy, M., Zhou, L., Differentiated QoS for survivable WDM optical networks (2004) Communications Magazine, 42, pp. S8-S14. , MayJukan, A., Van As, H.R., Service-specific wavelength allocation in QoS-routed optical networks (1998) IEEE GLOBECOM'98, 4, pp. 2270-2275. , Nov(2002) Spectral Grids for WDM Application: DWDM Frequency Grid, , ITU-T Rec. G.694.1, JunSong, S., Allen, C., Demarest, K., Pelz, L., Fang, X., Pua, Y., Experimental study of four wave mixing in non-zero dispersion fiber (1997) Proc. IEEE LEOS '97, 2, pp. 224-225. , NovXu, B., Brandt-Pearce, M., Comparison of FWM- and XPM-induced crosstalk using the Volterra series transfer function method (2003) J. Ligthwave Technology, 21, pp. 40-53. , JanSong, S., Allen, C.T., Demarest, K.R., Hui, R., Intensity-dependent phase-matching effects on four-wave mixing in optical fibers (1999) J. Lightwave Tecnology, 17, pp. 2285-2290. , NovInoue, K., A simple expression for optical FDM network scale considering fiber FWM and optical amplifier noise (1995) J. Ligthwave Technology, 13, pp. 856-861. , MayZang, H., Jue, J.P., Mukherjee, B., A review of routing and wavelength assignment approaches for wavelength-routed optical WDM networks (2000) SPIE Optical Network Magazine, 1, pp. 47-60. , DecFonseca, I.E., Ribeiro, M.R.N., Almeida Jr., R.C., Waldman, H., Meeting optical QoS in dynamic networks with reduced complexity (2004) Proc. ECOC'04, 3, pp. 750-751. , paper We4P141, SeptAgrawal, G.P., (2001) Nonlinear Fiber Optics, 3rd Ed, , San Diego, CA: Academic Press