Software Defined Networking and Network Function Virtualization: bridging the world of virtual networks

Roberto Morabito Department of Communications and Networking (Comnet), Aalto University, Espoo, Finland [email protected]

Abstract— Software Defined Networking (SDN) and Network Function Virtualization (NFV) are two emerging and complementary concepts that can be considered as key players in the virtual networks world. In particular, SDN allows managing different network services through abstraction of higher-level functionality, while NFV leverages the use of virtualization technologies to virtualize specific network functions. Although SDN and NFV are considered stand-alone technologies, they are often put in relationship, because their connections, and overlapped use cases. In this paper, we present a short survey providing an overview of the two different models, highlighting the complementarities, together with the standardization activities and the open source community efforts to make these two paradigms connected to each other.

Keywords—Software Defined Networking; SDN; Network Function Virtualization; NFV;

I. INTRODUCTION Fig. 1. SDN architecture [4] [INTRODUCTION] à [1,2,3] The remainder of this paper is organized as follows. In Section II, we summarize general background information B. Network Function Virtualization (NFV) about Software Defined Networking (SDN), and Network Function Virtualization (NFV). Section III clarifies the distinctions between SDN and NFV, however emphasizing [6], [7] point of contact and common use cases. In Section IV, a quick overview of ongoing standardization efforts is presented, together with the activities of the Open Source community in the virtual networks world. Section V concludes the paper providing final remarks.

II. BACKGROUND In this section, we provide an overview of the different approaches, which are object of the paper. A. Software Defined Networking (SDN)

[4], [5] Fig. 2. From dedicated hardware-based appliances for network services to software-based NFV solutions. [6]

III. SDN AND NFV: DIFFERENCES AND RELATIONS This section provides...

[SECTION III] à [8], [9]

problems that relate not just to networking but also to computing and storage aspects in such environments.

TABLE I.

MAIN STANDARDIZAION ACTIVITIES Standardization Scope Organization

ONF

ETSI

Fig. 3. SDN example with NFV domains inside [9] IRTF

IV. STANDARDIZATION EFFORTS AND OPEN SOURCE ACTIVITIES B. Open Source community activities The aim of this paragraph is to highlight, what are the main activities carried out within the main standardization entities In order to boost a common strategy towards the regarding SDN and NFV. Moreover, an overview of the main employment of SDN/NFV and related technologies, a huge Open Source project – always in this area – is presented. effort has been produced by industrial or community consortia, supporting different ongoing projects (e.g., A. Standardization Efforts OpenDaylight, OpenStack, OPNFV). The aim of these The standardization activities in SDN and NFV are already projects is to overcome possible difficulties within wide and are expected to keep evolving over time. standardization bodies, by working in open source implementations delivering products often considered • The Open Networking Foundation (ONF) [10] is an candidates for de facto standards. organization, funded by several companies – such as Below, it is possible to find an overview of the main Open Facebook, Google, Microsoft, and Yahoo! – whose Source projects. purpose is to promote and develop newer network paradigms through software-defined networking (SDN). • The OpenDaylight Project [14] is a collaborative open The of the OpenFlow protocol and related technologies source project hosted by The . The goal can still be considered the main activity of the of the project is to accelerate the adoption of software- organization. defined networking (SDN) and create a solid foundation for Network Functions Virtualization (NFV). • In 2012, a specification group – "Network Functions Virtualisation" – of the European Telecommunications • The Open Platform for NFV (OPNFV) [15] is an open Standards Institute (ETSI) [2], published the first white source project, which focuses on accelerating the adoption paper in which the NFV concept was introduced. After of the NFV paradigm, through an integrated and open the publication of the white paper, the ETSI–ISG NFV platform. Started by the Linux Foundation, the funding group has produced several documents, in which are consortium includes companies such as AT&T, Brocade defined several aspects related with the NFV world: Communications Systems, Cisco, , , Hewlett- standard terminology definition, use cases, security Packard, , IBM, , , NEC, concerns etc. All these documents can be considered as Nokia Networks, NTT DoCoMo, , etc. guidelines and act as references for actors orientend on implementing NFV. TABLE II. MAIN OPEN SOURCE PROJECTS The IRTF Software-Defined Networking Research • Open Source Scope Group (SDNRG [11]) investigates SDN from various Project perspectives with the goal of identifying the approaches OpenDaylight that can be defined, deployed and used in the near term as well identifying future research challenges. In particular, OPNFV key areas of interest include solution scalability, abstractions, and programming languages and paradigms [OPENDAYLIGHT DESCRIPTION] particularly useful in the context of SDN. In addition, it is an explicit goal of the SDNRG to provide a forum for researchers to investigate key and interesting problems in the Software-Defined Networking field. The IRTF Network Function Virtualization Research Group (NFVRG [12]) will bring together researchers and grow the community around the world in both academia and industry to explore this new research area. The NFVRG will focus on research problems associated with NFV-related topics and on bringing a research community together that can jointly address them, concentrating on V. CONCLUSION In this paper,

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