To satisfy the severe requirements involved in future communication networks, commercial and research interest in the applicability of wavelength division multiplexing (WDM) is growing. However, since WDM is merely concerned with transmitting bits over optical fibers, full advantage can only be taken when WDM is efficiently supported by higher-layer protocols. Functionality of higher-layer protocols that could be used in conjunction with WDM originates from synchronous digital hierarchy (SDH) or synchronous optical network (SONET), asynchronous transfer mode (ATM), and the internet protocol (IP). To provide flexible use of services with different levels of quality, various higher-layer protocols may directly support WDM simultaneously by reserving wavelength channels for a specific supporting protocol. Focussing on aspects of network management, this paper investigates how the mentioned higher-layer protocols may concurrently support WDM.