# From Brown-Field to Future Industrial Networks, a Case Study
## 6 Conclusions  
In future industries, communication barriers between IT and OT systems are going to be removed. The network infrastructures need to accommodate, manage and guarantee the performance of the merged IT-OT traffic. The pace of developments so far has been disproportionate to all the presumed benefits of converged networks for enabling innovative applications in future industries. Lack of clarity over brown-field configurations and operations, performance criteria and requirements of the converged networks and contradicting requirements of IT and OT traffics are some of the causes behind the lagging advances.  
The presented case study showed the unsatisfactory performance of the common assumptions and theoretical methods when applied to brown-field data. The comparison between the results of exploratory analysis of the brown-field and the theoretical approaches in the literature showed dissimilarities among the common assumptions and the real deployments. This additional insight is a step towards improving the accuracy of the brown-field characterization for future integration and performance management. The unsatisfactory performance of the commonly used methods for network configuration and performance management in terms of scalability and flexibility also questioned the suitability of common methods for brown-fields and further for converged networks.  
The proposed network-level measurement and characterization demonstrates suitability for brown-field data analysis for performance and resource management purposes, specifically when the scalability and flexibility of the converged networks are considered. The network-level view enables performance and resource estimation with the minimum footprint on the ongoing operations. This method needs to be further investigated to identify the important characteristics of the networks traffic, and quantify the impacts of these parameters into measurable performance criteria, as it is set for our future work.  
There are still many challenges in the path for the realization of converged networks in brown-fields, from identifying probable use-case scenarios where this realization provides the most benefits to finding the best technical and engineering approach for actualizing them. Nonetheless, the road map for moving toward the next evolutionary stage of industrial networks from brown-fields cannot be forged without capturing the essence of brown-field operational states.  
Conceptualization, J.A., M.B. and M.L.; methodology, experiments and visualization, M.L.; writing--original draft preparation, review and editing, M.L.; review, supervision, J.A.; project administration, funding acquisition, J.A. and M.B. All authors have read and agreed to the published version of the manuscript.  
This work has been partly financed by the Future Industrial Networks project, grant number 2018-02196, within the Strategic innovation program for process industrial IT and Automation, PiA, a joint program by Vinnova, Formas and Energimyndigheten.  
Not applicable.  
The data presented in this study are available on request from the corresponding author.  
We would like to thank the reviewers for their constructive comments that helped to improve the context of this manuscript.  
The authors declare no conflict of interest.