Automated Network Service Scaling in NFV: Concepts, Mechanisms and Scaling Workflow Adamuz Hinojosa, Óscar Ramón Ordoñez Lucena, José Ameigeiras Gutiérrez, Pablo José Ramos Muñoz, Juan José López, Diego Folgueira Chavarría, Jesús NFV ETSI network service scaling automation This work is partially supported by the Spanish Ministry of Economy and Competitiveness, the European Regional Development Fund (Project TEC2016-76795-C6-4-R), the Spanish Ministry of Education, Culture and Sport (FPU Grant 16/03354), and the University of Granada, Andalusian Regional Government and European Social Fund under Youth Employment Program. Next-generation systems are anticipated to be digital platforms supporting innovative services with rapidly changing traffic patterns. To cope with this dynamicity in a cost-efficient manner, operators need advanced service management capabilities such as those provided by NFV. NFV enables operators to scale network services with higher granularity and agility than today. For this end, automation is key. In search of this automation, the European Telecommunications Standards Institute (ETSI) has defined a reference NFV framework that make use of model-driven templates called Network Service Descriptors (NSDs) to operate network services through their lifecycle. For the scaling operation, an NSD defines a discrete set of instantiation levels among which a network service instance can be resized throughout its lifecycle. Thus, the design of these levels is key for ensuring an effective scaling. In this article, we provide an overview of the automation of the network service scaling operation in NFV, addressing the options and boundaries introduced by ETSI normative specifications. We start by providing a description of the NSD structure, focusing on how instantiation levels are constructed. For illustrative purposes, we propose an NSD for a representative NS. This NSD includes different instantiation levels that enable different ways to automatically scale this NS. Then, we show the different scaling procedures the NFV framework has available, and how it may automate their triggering. Finally, we propose an ETSI-compliant workflow to describe in detail a representative scaling procedure. This workflow clarifies the interactions and information exchanges between the functional blocks in the NFV framework when performing the scaling operation. 2021-04-29T12:10:43Z 2021-04-29T12:10:43Z 2018-07 journal article O. Adamuz-Hinojosa, J. Ordonez-Lucena, P. Ameigeiras, J. J. Ramos-Munoz, D. Lopez and J. Folgueira, "Automated Network Service Scaling in NFV: Concepts, Mechanisms and Scaling Workflow," in IEEE Communications Magazine, vol. 56, no. 7, pp. 162-169, July 2018, doi: 10.1109/MCOM.2018.1701336. http://hdl.handle.net/10481/68205 10.1109/MCOM.2018.1701336 eng http://creativecommons.org/licenses/by-nc-nd/3.0/es/ open access Atribución-NoComercial-SinDerivadas 3.0 España IEEE