rated from that in the data plane. In the GMPLS original version, the network manager has only the role of defining the net- work when it is initialized and of reporting network events to the central network control room. Moreover, the network manager also implements traffic engineering tools that can be run off line on the network manager workstation to verify if the network is optimized. If the connection routing and resource assignment is not optimized, as surely will happen after a certain period of network working, the network manager is able to force the network to exit from the present configuration to assume a better one, for example, rerouting some paths. This original role of the network manager in GMPLS networks is completely different from what is prescribed from ASON and probably at the end of the Control plane with ring topology FIGURE 8.8 Communication structure dedicated to the control plane and its indepen- dence from the network on the data Data plane with plane. full mesh topology Convergent Network Management and Control Plane story the ASON version will prevail if not for other reasons since it is pushed from the network owners. GMPLS uses generalized labels to perform routing of generalized label switched path (GLSP). In contrast to MPLS where labels merely represent network traffic, generalized labels represent network resources. For example, a generalized label on an optical link could identify a wavelength or a fiber, while on a packet-switched link, it would simply identify network traffic, just as in MPLS. In the lower layers, generalized labels are "vir- tual," meaning that they are not inserted into the network traffic, but instead implied by the network resource being used (e.g., wavelength or fiber). This is necessary since neither packets nor frames are recognized at the lowest layers that GMPLS supports. Generalizing the label format, the conventional MPLS label has been extended to 32 bits. The labeling of ports of routing equipment in GMPLS follows a particular convention that a