Parallel lightpath provisioning under wavelength continuity constraint in multi-domain optical networks based on hierarchical path computation element

Inter-domain path provision under a wavelength continuity constraint (WCC), including path computation and resource reservation procedures, is a major challenge in multi-domain wavelength division multiplexing (WDM) optical networks, because of the requirement for confidentiality between the domains. Based on the hierarchical path computation element (PCE) architecture, this work proposed a path establishment scheme under a WCC to provide a fast inter-domain path establishment solution and decrease the influence of the WCC. The hierarchical PCE architecture consists of a single parent PCE serving as the arbitrator and multiple child PCEs responsible for the child domains. By cooperation between the parent PCE and the child PCEs, both inter-domain path computation and inter-domain wavelength reservation can be processed in parallel to accelerate and optimize WCC lightpath provisioning and thus to reduce the blocking probability. The effectiveness of this solution has been evaluated through simulations. The simulation results show that the proposed solution can achieve lower computation and reservation delays and thus lead to lower blocking probabilities on the multi-domain WCC paths.