Summary

The increasing demand for sophisticated network applications, allied to the growth of the Internet traffic, has lead to great efforts in the search of improvements in data transmission technologies with the intention of satisfying the increasing demand for bandwidth. So far as optical networking is concerned, WDM (Wavelength Division Multiplexing) appears as the main advance in the transmission area, because it allows transmission rates near to the theoretical limit of optical fibers, of the order of dozens of terabits a second [1]. An essential issue in optical network design is defining how the network will be controlled, that is, what type of signalling will be responsible for resource reservation, route determination and fault handling, among other functions that constitute the control plane. Label switching, which in IP networks is exemplified by MPLS (Multiprotocol Label Switching) [2], was extended through GMPLS (Generalized Multiprotocol Label Switching) [3] to operate with several different network technologies, where the label can be represented in other ways, for example, as time-slots in TDM networks, as physical switch ports and as wavelengths (lambdas) in WDM networks.