Emulating software-defined disaggregated optical networks in a containerized framework

Telecom operators’ infrastructure is undergoing high pressure to keep the pace with the traffic demand generated by the societal need of remote communications, bandwidth-hungry applications, and the fulfilment of 5G requirements. Software-defined networking (SDN) entered in scene decoupling the data-plane forwarding actions from the control-plane decisions, hence boosting network programmability and innovation. Optical networks are also capitalizing on SDN benefits jointly with a disaggregation trend that holds the promise of overcoming traditional vendor-locked island limitations. In this work, we present our framework for disaggregated optical networks that leverages on SDN and container-based management for a realistic emulation of deployment scenarios. Our proposal relies on Kubernetes for the containers’ control and management, while employing the NETCONF protocol for the interaction with the light-weight software entities, i.e., agents, which govern the emulated optical devices. Remarkably, our agents’ structure relies on components that offer high versatility for accommodating the wide variety of components and systems in the optical domain. We showcase our proposal with the emulation of an 18-node European topology employing Cassini-compliant optical models, i.e., a state-of-the-art optical transponder proposed in the Telecom Infrastructure Project. The combination of our versatile framework based on containerized entities, the automatic creation of agents and the optical-layer characteristics represents a novel approach suitable for operationally complex carrier-grade transport infrastructure with SDN-based disaggregated optical systems.This research was funded Spanish Government: ONOFRE-2 project under Grant TEC2017-84423-C3-2-P (MINECO/AEI/FEDER, UE) and the Go2Edge project under Grant RED2018-102585-T; and by the European Commission: METRO-HAUL project (G.A. 761727)

Experimental Validation of Time-Synchronized Operations for Software-Defined Elastic Optical Networks

Elastic optical networks (EON) have been proposed as a solution to efficiently exploit the spectrum resources in the physical layer of optical networks. Moreover, by centralizing legacy generalized multiprotocol label switching control-plane functionalities and providing a global network view, software-defined networking (SDN) enables advanced network programmability valuable to control and configure the technological breakthroughs of EON. In this paper, we review our recent proposal [Optical Fiber Communication Conf., Los Angeles, California, 2017] of time-synchronized operations (TSO) to minimize disruption time during lightpath reassignment in EON. TSO has been recently standardized in SDN, and here we discuss its implementation using NETCONF and OpenFlow in optical networks. Subsequently, we update our analytical model considering an experimental characterization of the WSS operation time. Then, we extend our previous work with an experimental validation of TSO for lightpath reassignment in a five-node metropolitan optical network test-bed. Results validate the convenience of our TSO-based approach against a traditional asynchronous technique given its reduction of disruption time, while both techniques maintain a similar network performance in terms of optical signal-to-noise ratio and optical power budget

Optical Network Models and their Application to Software-Defined Network Management

Software-defined networking is finding its way into optical networks. Here, it promises a simplification and unification of network management for optical networks allowing automation of operational tasks despite the highly diverse and vendor-specific commercial systems and the complexity and analog nature of optical transmission. A fundamental component for software-defined optical networking are common abstractions and interfaces. Currently, a number of models for optical networks are available. They all claim to provide open and vendor agnostic management of optical equipment. In this work, we survey and compare the most important models and propose an intent interface for creating virtual topologies that is integrated in the existing model ecosystem.Comment: Parts of the presented work has received funding from the European Commission within the H2020 Research and Innovation Programme, under grant agreeement n.645127, project ACIN

Software Defined Applications in Cellular and Optical Networks

abstract: Small wireless cells have the potential to overcome bottlenecks in wireless access through the sharing of spectrum resources. A novel access backhaul network architecture based on a Smart Gateway (Sm-GW) between the small cell base stations, e.g., LTE eNBs, and the conventional backhaul gateways, e.g., LTE Servicing/Packet Gateways (S/P-GWs) has been introduced to address the bottleneck. The Sm-GW flexibly schedules uplink transmissions for the eNBs. Based on software defined networking (SDN) a management mechanism that allows multiple operator to flexibly inter-operate via multiple Sm-GWs with a multitude of small cells has been proposed. This dissertation also comprehensively survey the studies that examine the SDN paradigm in optical networks. Along with the PHY functional split improvements, the performance of Distributed Converged Cable Access Platform (DCCAP) in the cable architectures especially for the Remote-PHY and Remote-MACPHY nodes has been evaluated. In the PHY functional split, in addition to the re-use of infrastructure with a common FFT module for multiple technologies, a novel cross functional split interaction to cache the repetitive QAM symbols across time at the remote node to reduce the transmission rate requirement of the fronthaul link has been proposed.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

OSNR Aware Composition of an Open and Disaggregated Optical Node and Network

A function programmable optical network has been recently proposed to enhance the flexibility of an optical transport based on architecture-on-demand (AoD). The flexible synthesis of optical node architectures provided by AoD enables an open and disaggregated optical layer thanks to the available deep programmability. However, previous studies have focused on how to synthesize a single node out of switching function blocks, thus neglecting the optical signal-to-noise ratio (OSNR) impact, power imbalance effects due to the diverse set of devices traversed per input–output configuration, and network-wide implications. In this work, we present an optical network-wide function synthesis (ONetFuS), which is an algorithm to compose AoD nodes that consider placement and configuration of both switches and amplifiers. ONeFuS minimizes OSNR degradation and deviation across channels and offers enhanced power balance performance. Moreover, ONetFuS addresses multiple-node scenarios to investigate cascading, transmission distance, and networking effects. We compare the number of optical cross-connections computed by our proposal against solutions in the literature. Results in network scenarios, including the number of components, power balance, OSNR variations, and OSNR penalty reductions, prove the suitability of our proposed ONetFuS for open and functional programmable optical networks

Network service chaining using segment routing in multi-layer networks

Network service chaining, originally conceived in the network function virtualization (NFV) framework for software defined networks (SDN), is becoming an attractive solution for enabling service differentiation enforcement to microflows generated by data centers, 5G fronthaul and Internet of Things (IoT) cloud/fog nodes, and traversing a metro-core network. However, the current IP/MPLS-over optical multi-layer network is practically unable to provide such service chain enforcement. First, MPLS granularity prevents microflows from being conveyed in dedicated paths. Second, service configuration for a huge number of selected flows with different requirements is prone to scalability concerns, even considering the deployment of a SDN network. In this paper, effective service chaining enforcement along traffic engineered (TE) paths is proposed using segment routing and extended traffic steering mechanisms for mapping micro-flows. The proposed control architecture is based on an extended SDN controller encompassing a stateful path computation element (PCE) handling microflow computation and placement supporting service chains, whereas segment routing allows automatic service enforcement without the need for continuous configuration of the service node. The proposed solution is experimentally evaluated in segment routing over an elastic optical network (EON) network testbed with a deep packet inspection service supporting dynamic and automatic flow enforcement using Border Gateway Protocol with Flow Specification (BGP Flowspec) and OpenFlow protocols as alternative traffic steering enablers. Scalability of flow computation, placement, and steering are also evaluated showing the effectiveness of the proposed solution

Control Plane in Software Defined Networks and Stateful Data Planes

L'abstract è presente nell'allegato / the abstract is in the attachmen