A Scalable Telemetry Framework for Zero Touch Optical Network Management

The interest about Zero Touch Network and Service Management (ZSM) is rapidly emerging. As defined by ETSI, the ZSM architecture is based on a closed-loop/feedback control of the network and the services. Such closed-loop control can be based on the Boyd's Observe Orient Decide and Act (OODA) loop that matches some specific management functions such as Data Collection, Data Analytics, Intelligence, Orchestration and Control. An efficient implementation of such control loop allows the network to timely adapt to changes and maintain the required quality of service.Many solutions for collecting network parameters (i.e., implementing ZSM data collection) are proposed that fall under the broad umbrella of network telemetry. An example is the Google gRPC, that represented one of the first solutions to provide a framework for data collection. Since then, the number of available frameworks is proliferating. In this paper we propose the utilisation of Apache Kafka as a framework for collecting optical network parameters. Then, the paper goes beyond that by proposing and showing how Apache Kafka can be effective for supporting data exchange and management of whole ZSM closed-loop.Experimental evaluation results show that, even when a large number of data are collected, the solution is scalable and the time to disseminate the parameter values is short. Indeed, the difference between the reception time and the generation time of data is, on average, 40-50ms when about four thousand messages are generated

Encapsulation Techniques and Traffic Characterisation of an Ethernet-Based 5G Fronthaul

This paper first overviews how, in the 5G Next Generation Radio Access Network (NG-RAN), the Next generation NodeB (gNB) functions are split into Distributed Unit (DU) and Central Unit (CU). Then it describes the proposed fronthaul transport solutions, such as Common Packet Radio Interface (CPRI), eCPRI, IEEE P1914.3 and their relationship with the Ethernet protocol. Finally, a characterisation of the traffic generated by the fronthaul is presented. Such characterisation may guide in the selection of the right network for fronthaul transport.This work has been partially funded by the EU H2020 “5G-Transformer” Project (grant no. 761536)

Orchestrating Lightpath Recovery and Flexible Functional Split to Preserve Virtualized RAN Connectivity

In the next-generation radio access network (NG RAN), the next-generation evolved NodeBs (gNBs) will be, likely, split into virtualized central units (CUs) and distributed units (DUs) interconnected by a fronthaul network. Because of fronthaul latency and capacity requirements, optical metro-ring networks are among the main candidates for supporting converged 5G and non-5G services. In this scenario, a degradation in the quality of transmission of the lightpaths connecting DU and CU can be revealed (or anticipated) based on monitoring techniques. Thus, the lightpath transmission parameters can be adapted to maintain the required bit error rate (BER). However, in specific cases, the original requested capacity between DU and CU could be not guaranteed, thus impacting the service. In this case, another DU–CU connectivity should be considered, relying on a change of the so-called functional split. This study proposes a two-step recovery scheme orchestrating lightpath transmission adaptation and functional split reconfiguration to guarantee the requested connectivity in a virtualized RAN fronthaul. Results show that, for the connections that cannot be transported by the original lightpath, a graceful degradation followed by a recovery is possible within tens of seconds.This work was partly funded by the project H2020-ICT-2016-2 “5G-TRANSFORMER” (761536

Energy efficient optical access and metro networks

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Impact of Virtualization Technologies on Virtualized RAN Midhaul Latency Budget: A Quantitative Experimental Evaluation

In the Next Generation Radio Access Network (NGRAN) defined by 3GPP for the fifth generation of mobile communications (5G), the next generation NodeB (gNB) is split into a Radio Unit (RU), a Distributed Unit (DU), and a Central Unit (CU). RU, DU, and CU are connected through the fronthaul (RU-DU) and midhaul (DU-CU) segments. If the RAN is also virtualised RAN (VRAN), DU and CU are deployed in virtual machines or containers. Different latency and jitter requirements are demanded on the midhaul according to the distribution of the protocol functions between DU and CU. This study shows that, in VRAN, the virtualisation technologies, the functional split option, and the number of elements deployed in the same computational resource affect the latency budget available for the midhaul. Moreover, it provides an expression for the midhaul allowable latency as a function of the aforementioned parameters. Finally, it shows that, the virtualised DUs featuring a lower layer split option shall be deployed not in the sameThis work has been partially funded by the EC H2020 “5G-Transformer” Project (grant no. 761536)

Challenges and Requirements for Introducing Impairment-awareness into the Management and Control Planes of ASON/GMPLS WDM Networks

The absence of electrical regenerators in transparent WDM networks significantly contributes to reduce the overall network cost. In transparent WDM networks, a proper resource allocation requires that the presence of physical impairments in Routing and Wavelength Assignment (RWA) and lightpath provisioning be taken into account. In this article a centralized, a hybrid centralized-distributed and two distributed approaches that integrate information about most relevant physical impairments in RWA and lightpath provisioning are presented and assessed. Both centralized and hybrid approaches perform a centralized path computation at the management-plane level, utilizing physical impairment information, while the lightpath provisioning is done by the management plane or the control plane, respectively. The distributed approaches fall entirely within the scope of the ASON/GMPLS control plane. For these two approaches, we provide functional requirements, architectural functional blocks, and protocol extensions for implementing either an impairment-aware real-time RWA, or a lighpath provisioning based on impairment-aware signaling

Experimental Demonstration of a 5G Network Slice Deployment Through the 5G-Transformer Architecture

44th European Conference on Optical Communications (ECOC 2018)This demo shows for the first time the capability of the proposed 5G-TRANSFORMER architecture to deploy a 5G network slice in minutes. The slice consists of a mix of physical and virtual mobile network functions deployed in an Openstack environment.This work was supported by the EC through the Horizon 2020 5G-TRANSFORMER project (grant agreement 761536)