Ll. Gifre

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

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, subconnections , 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 subconnections count by aggregating those belonging to the same original connection and rerouting the resulting connection to release spectral resources. The MP-AFRO problem is modeled using a mixed integer linear program 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 tradeoff 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 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).

iONE: A workflow-oriented ABNO implementation

An implementation of the IETF standardized ABNO architecture, named as iONE is presented. iONE consists in one single generic configurable module and a set of dynamically linkable workflows. The spectrum defragmentation use case is used to experimentally demonstrate iONEs functionalities.

First demonstration of multi-vendor and multi-domain EON with S-BVT and control interoperability over Pan-European testbed

The operation of multi-domain and multi-vendor EONs can be achieved by interoperable Sliceable Bandwidth Variable Transponders, a GMPLS/BGP-LS-based control plane and a planning tool. This paper reports the first full demonstration and validation this end-to-end architecture.

Experimental demonstration of brokered orchestration for end-to-end service provisioning and interoperability across heterogeneous multi-operator (multi-AS) optical networks

A broker on top of opaquely-managed optical domains advertising their capabilities is proposed to provision multi-AS connections in multi-operator scenarios. In case of no spectrum continuity, intra-domain spectral defragmentation is performed. Experimental assessment was conducted on a distributed multi-continental infrastructure.

Experimental validation of active frontend — Backend stateful PCE operations in flexgrid optical network re-optimization

A PCE-based strategy for LSP re-optimization in flexgrid optical networks is experimentally validated. A front- and back-end stateful PCE architecture is deployed, wherein automatic and coordinated operations (e.g., computation delegation, database synchronization, etc.) are demonstrated using PCEP and BGP-LS protocols.

Dynamic core VNT adaptability based on predictive metro-flow traffic models

MPLS-over-optical virtual network topologies (VNTs) can be adapted to near-future traffic matrices based on predictive models that are estimated by applying data analytics on monitored origin-destination (OD) traffic. However, the deployment of independent SDN controllers for core and metro segments can bring large inefficiencies to this core network reconfiguration based on traffic prediction when traffic flows from metro areas are rerouted to different ingress nodes in the core. In such cases, OD traffic patterns in the core might severely change, thus affecting the quality of the predictive OD models. New traffic model re-estimation usually takes a long time, during which no predictive capabilities are available for the network operator. To alleviate this problem, we propose to extend data analytics to metro networks to obtain predictive models for the metro flows; by knowing how these flows are aggregated into OD pairs in the core, we can also aggregate their predictive models, thus accurately predicting OD traffic and therefore enabling core VNT reconfiguration. To obtain quality metro-flow models, we propose an estimation algorithmthat processes monitored data and returns a predictive model. In addition, a flow controller is proposed for the control architecture to allow metro and core controllers to exchange metro-flow model information. The proposed model aggregation is evaluated through exhaustive simulation, and eventually experimentally assessed together with the flow controller in a testbed connecting premises in CNIT (Pisa, Italy) and UPC (Barcelona, Spain).

Modulation format-aware re-optimization in flexgrid optical networks: Concept and experimental assessment

A modulation format-aware algorithm to re-optimize resource utilization after a link repair is proposed. The proposed workflow implemented on an ABNO architecture and protocol extensions for SBVT and modulation format selection are experimentally assessed in a distributed test-bed.

Modulation format-aware restoration and re-optimization in Flexgrid optical networks

Sliceable Bandwidth-variable Transponders (SBVTs) enhance the configurability and flexibility of Flexgrid optical networks. A single SBVT can be used to transmit and receive several optical signals each modulated with a specific format. A SBVT can be seen as a set of sub-transponders that can be specifically configured to end a specific lightpath, by defining, among other parameters, the modulation format and the central frequency to be used. Modulation formats are characterized by its spectrum efficiency and reachability. In this paper, we propose modulation format-aware algorithms to restore connections affected by a link failure, as well as to re-optimize resource utilization after a link repair.