A novel signaling approach to encompass physical impairments in GMPLS networks

Next generation networks are expected to be characterized by domains of transparency in which a GMPLS common control plane is adopted to manage both the IP layer and the optical transport layer. Within domains of transparency the end-to-end lightpath signal quality has to be guaranteed. However, currently, GMPLS does not take into account the evaluation of physical impairments. Thus just limited size domains of transparency are practically achievable. In this study a novel approach to dynamically estimate the end-to-end signal quality is proposed. The method is based on the introduction, into current GMPLS signaling and management protocols, of extensions which encompass the physical parameters that characterize the optical transport layer. The proposed approach allows to detect whether lightpaths cannot be set up because of accumulated linear physical impairments during their signaling phase. Numerical results show that the lightpath blocking probability due to physical impairments decreases by implementing suitable routing policies, such as multiple attempts. Thus few very impaired links can be introduced into large domains of transparency without affecting the overall network performance. An experimental implementation based on PXC and IP routers is also presented to validate the feasibility of the proposed approach.