First Experimental Assessment of ABNO-Driven In-Operation Flexgrid Network Re-Optimization

Abstract

Abstract-Traffic affected by link failures can be recovered using path restoration schemes. In dynamically operated networks provided with a control plane, restoration algorithms run in a centralized element, such as the Path Computation Element (PCE). To increase traffic restorability in flexgrid networks, multiple paths, sub-connections, can be used to restore every single affected connection. However, the multipath restoration scheme might result in a poor resource utilization entailing a lesser grade of service. In-operation network planning algorithms can be used to mitigate this problem once the failed link is repaired; we propose solving the so-called multipath after failure repair optimization problem (MP-AFRO) to reduce sub-connections count by aggregating those belonging to the same original connection and re-routing the resulting connection to release spectral resources. The MP-AFRO problem is modelled using a Mixed Integer Linear Program (MILP) formulation. In view of the complexity of the model and the limited time to solve the problem, we propose a heuristic algorithm that provides a good trade-off between complexity and optimality. The performance on the MP-AFRO heuristic is firstly validated by simulation. Next, the heuristic algorithm is deployed inside an in-operation planning tool in the form of back-end PCE (bPCE) inside the Application-based Network Operations (ABNO) architecture controlling a network; the bPCE is connected to the centralized active stateful PCE. MP-AFRO is experimentally demonstrated using a distributed field trial test-bed connecting the premises of Telefonica (Madrid), CNIT (Pisa), and UPC (Barcelona).

Open Network Database for Application-Based Control in Multilayer Networks

“…Efficient traffic grooming strategies encapsulating PSC LSPs over EON lightpaths have been studied also in the context of software defined networking (SDN) framework [8]. Inter-layer applicability has been assessed in different testbeds, mainly based on PCE and the Application Based Network Operation (ABNO) architecture [9], [10]. Work in [11] proposes multi-layer restoration using global concurrent optimization for bulk restoration of LSPs.…”

“…IV-A. The C++-based LSC PCE implementation derives from [10] and supports stateful provisioning and update of flex-grid Elastic Optical Networks (EON) lightpaths with transponder extensions as in [21]. The considered C++ PSC PCE operates on IP/MPLS networks and is derived from the implementation described in [22], also supporting Segment Routing extensions.…”

Open Database for Interconnected Traffic Engineered Multi-Layer Networks

“…1 is considered. The testbed includes the C++ LSC PCE implementation derived from [3] and supporting flex-grid EON and transponder extensions as in [4]. The considered C++ PSC PCE is derived from [5], also supporting Segment Routing extensions.…”

Core Networks in the Flexgrid Era

“…This virtualization of resources and presenting some control of them directly to users forms the basis of research into transport-software defined networks [30]. This is a rich and active area of research as well as standardization activity, with significant progress being made [31], [32].…”