# Towards Flexible Integration of 5G and IIoT Technologies in Industry 4.0: A Practical Use Case
## 1 Introduction
Most of these IIoT applications comprise small sensors with limited capabilities and resources, named Constrained Device Sensor (CDS). These interconnected sensors form a Wireless Sensor Network (WSN), in which the CDSs are able to communicate with each other making use of suitable communication protocols. IIoT technologies enable the achievement of most of the Industry 4.0 main objectives, such as the increase of the manufacturing process efficiency, the reduction of production times, and the improvement of the user experience. However, the integration of WSNs into industrial environments comes with security issues that must be overcome. The wireless nature of the sensors comprising the WSN and their limited processing capacity leads to a higher vulnerability to attacks. This implies the need of introducing robust security mechanisms that avoid unauthorized attacks such as data tampering or data filtration. Moreover, as these devices do not support traditional security mechanisms due to their heavy constraints, protecting these devices is not straightforward, becoming a hindrance to achieving secure IIoT applications. The objectives of the present article are threefold. The first objective is to develop an NFV- and SDN-enabled architecture capable of overcoming the aforementioned limitations. In this regard, the pursued goals are to move away from static solutions over dedicated hardware and evolve towards the more cost- and resource-efficient virtualization and softwarization mechanisms; improve the accessibility, reusability, and lifecycle management of services; and provide highly granular service isolation at data and performance levels. To realize this first objective, the introduction of Smart Networks for Industry (SN4I) is proposed, an NFV- and SDN-enabled experimental facility deployed across the Faculty of Engineering in Bilbao (EIB) and the Aeronautics Advanced Manufacturing Center (CFAA). SN4I has been envisioned to study the integration of NFV and SDN technologies in coexistence with industrial networks and protocols whilst enabling the deployment of innovative manufacturing services leveraging the benefits of these technologies. The second objective is to integrate several CDSs in a WSN supported by the NFV- and SDN-enabled infrastructure to make possible the integration of IIoT applications. These IIoT applications will be strengthened by the use of a lightweight access control protocol that prevents them from receiving unauthorized accesses to the sensors and improves the security vulnerabilities that wireless scenarios entail. Moreover, this protocol will also provide a dynamic and fine-grained access control between the users and the sensors, enabling a flexible behavior of the IIoT applications. The WSN will also leverage the benefits of SDN and NFV in regards to network slicing and overall flexibility, providing added dynamicity to the integration of sensor services into different processes. The third objective is to demonstrate a use case deployed over such infrastructure in a manufacturing center that also permits to validate the architecture. It consists of the monitoring of a broaching process in the CFAA through the integration of virtualized Machine Learning (ML) services to enhance the process, as well as services from the WSN for additional data gathering. To feed the ML algorithms, data from the broaching process will be collected from several broaching tool components, and, additionally, information related to environmental conditions will be gathered from the CDSs in the WSN. The description of the use case in the present article focuses on discussing how the services and components involved in this use case have been integrated into the proposed infrastructure. The article is structured as follows. Section 2 addresses the related work in the field of NFV and SDN technologies in industrial scenarios and the securization of IIoT applications.