Proactive H-PCE architecture with BGP-LS update for multidomain elastic optical networks [Invited]

The hierarchical path computation element (H-PCE) architecture has been proposed to perform effective end-to-end path computation in multidomain elastic optical networks (EONs). In the H-PCE architecture a single parent PCE is responsible for inter-domain path computations, while a dedicated child PCE performs intra-domain path computations within each domain. In this scenario, effective inter-domain path computation is achieved only if detailed and updated intra-domain resource availability information is locally stored or retrievable by the parent PCE. Border Gateway Protocol has been recently extended to transport link state information (BGP-LS) that can be used to update the resource availability information at the parent PCE, thus improving scalability and effectiveness of the H-PCE architecture. Specifically, BGP-LS speakers located at each child PCE have been demonstrated to update the parent PCE with per-link spectrum slices availability information triggered by the reception of local Interior Gateway Protocol (IGP) advertisements. This paper proposes a proactive scheme to update the parent PCE, in which the generation of BGP-LS updating messages is not dependant on the IGP advertisements but automatically triggered by path computation requests at the child PCEs. The proposed scheme is applied during provisioning and restoration phases in a multidomain EON scenario and compared against two reference schemes. Simulation results show a significant reduction in terms of blocking probability and amount of exchanged control plane messages.