Network function virtualization (NFV) has drawn significant attention from both industry and academia as an important shift in telecommunication service provisioning. By decoupling network functions (NFs) from the physical devices on which they run, NFV has the potential to lead to significant reductions in operating expenses (OPEX) and capital expenses (CAPEX) and facilitate the deployment of new services with increased agility and faster time-to-value. The NFV paradigm is still in its infancy and there is a large spectrum of opportunities for the research community to develop new architectures, systems and applications, and to evaluate alternatives and trade-offs in developing technologies for its successful deployment. In this paper, after discussing NFV and its relationship with complementary fields of software defined networking (SDN) and cloud computing, we survey the state-of-the-art in NFV, and identify promising research directions in this area. We also overview key NFV projects, standardization efforts, early implementations, use cases, and commercial products.

/pdf/network-function-virtualization-state-of-the-art-and-29gg3feprt.pdf

Network Function Virtualization: State-of-the-Art and Research Challenges

Network functions virtualization (NFV) is a new network architecture framework where network function that traditionally used dedicated hardware (middleboxes or network appliances) are now implemented in software that runs on top of general purpose hardware such as high volume server. NFV emerges as an initiative from the industry (network operators, carriers, and manufacturers) in order to increase the deployment flexibility and integration of new network services with increased agility within operator’s networks and to obtain significant reductions in operating expenditures and capital expenditures. NFV promotes virtualizing network functions such as transcoders, firewalls, and load balancers, among others, which were carried out by specialized hardware devices and migrating them to software-based appliances. One of the main challenges for the deployment of NFV is the resource allocation of demanded network services in NFV-based network infrastructures. This challenge has been called the NFV resource allocation (NFV-RA) problem. This paper presents a comprehensive state of the art of NFV-RA by introducing a novel classification of the main approaches that pose solutions to solve it. This paper also presents the research challenges that are still subject of future investigation in the NFV-RA realm.

Resource Allocation in NFV: A Comprehensive Survey

Integrating the various embedded devices and systems in our environment enables an Internet of Things (IoT) for a smart city. The IoT will generate tremendous amount of data that can be leveraged for safety, efficiency, and infotainment applications and services for city residents. The management of this voluminous data through its lifecycle is fundamental to the realization of smart cities. Therefore, in contrast to existing surveys on smart cities we provide a data-centric perspective, describing the fundamental data management techniques employed to ensure consistency, interoperability, granularity, and reusability of the data generated by the underlying IoT for smart cities. Essentially, the data lifecycle in a smart city is dependent on tightly coupled data management with cross-cutting layers of data security and privacy, and supporting infrastructure. Therefore, we further identify techniques employed for data security and privacy, and discuss the networking and computing technologies that enable smart cities. We highlight the achievements in realizing various aspects of smart cities, present the lessons learned, and identify limitations and research challenges.

Smart Cities: A Survey on Data Management, Security, and Enabling Technologies

Software defined networking (SDN) has emerged as a promising paradigm for making the control of communication networks flexible. SDN separates the data packet forwarding plane, i.e., the data plane, from the control plane and employs a central controller. Network virtualization allows the flexible sharing of physical networking resources by multiple users (tenants). Each tenant runs its own applications over its virtual network, i.e., its slice of the actual physical network. The virtualization of SDN networks promises to allow networks to leverage the combined benefits of SDN networking and network virtualization and has therefore attracted significant research attention in recent years. A critical component for virtualizing SDN networks is an SDN hypervisor that abstracts the underlying physical SDN network into multiple logically isolated virtual SDN networks (vSDNs), each with its own controller. We comprehensively survey hypervisors for SDN networks in this paper. We categorize the SDN hypervisors according to their architecture into centralized and distributed hypervisors. We furthermore sub-classify the hypervisors according to their execution platform into hypervisors running exclusively on general-purpose compute platforms, or on a combination of general-purpose compute platforms with general- or special-purpose network elements. We exhaustively compare the network attribute abstraction and isolation features of the existing SDN hypervisors. As part of the future research agenda, we outline the development of a performance evaluation framework for SDN hypervisors.

Survey on Network Virtualization Hypervisors for Software Defined Networking

Service function chaining is a network capability that provides support for application-driven-networking through the ordered interconnection of service functions. The lifecycle management of service function chains is enabled by two recently emerged technologies, software defined networking and network function virtualization, that promise a number of efficiency, effectiveness, and flexibility gains. This article introduces a service function chaining taxonomy that considers architecture and performance dimensions as the basis for the subsequent stateof- the-art analysis. The article concludes with a gap analysis of existing solutions and the identification of future research challenges.

Service Function Chaining in Next Generation Networks: State of the Art and Research Challenges

Deploying service functions, SFs, is an essential action for a network provider. However, the action of creating, modifying and removing network SFs is traditionally very costly in time and effort, requiring the acquisition and placement of specialized hardware devices and their interconnection. Fortunately, the emergence of concepts like cloud computing, SDN, and ultimately NFV is expected to raise new possibilities for the management of SFs with a positive impact in terms of agility and cost. From a telco viewpoint these concepts can help to both reduce OPEX and open the door to new business opportunities. In this article, we identify how teleos can benefit from the abovementioned paradigms, and explore some of the aspects that still need to be addressed in the NFV domain. We focus on two major aspects: enabling telco infrastructures to adopt this new paradigm, and orchestrating and managing SFs toward telco-ready cloud infrastructures. The technologies we describe enable a telco to deploy and manage SFs in a distributed cloud infrastructure. In this context, the Cloud4NFV platform is presented. Special attention is given to the way SFs are modeled toward cloud infrastructure resources. In addition, we explore the ability to perform service function chaining as one of the fundamental features in the composition of SFs. Finally, we describe a proof of concept that demonstrates how a telco can benefit from the described technologies.

Toward a telco cloud environment for service functions

The principle of Network Functions Virtualization (NFV) aims to transform network architectures by implementing Network Functions (NFs) in software that can run on commodity hardware. There are several challenges inherent to NFV, among which is the need for an orchestration and management framework. This paper presents the Cloud4NFV platform, which follows the major NFV standard guidelines. The platform is presented in detail and special attention is given to data modelling aspects. Further, insights on the current implementation of the platform are given, showing that part of its foundations lay on cloud infrastructure management and Software Defined Networking (SDN) platforms. Finally, it is presented a proof-of-concept (PoC) that illustrates how the platform can be used to deliver a novel service to end customers, focusing on Customer Premises Equipment (CPE) related functions.

Cloud4NFV: A platform for Virtual Network Functions

To meet the challenging key performance indicators of the fifth generation (5G) system, the network infrastructure becomes more heterogeneous and complex. This will bring a high pressure on the reduction of OPEX and the improvement of the user experience. Hence, shifting today's manual and semi-automatic network management into an autonomic and intelligent framework will play a vital role in the upcoming 5G system. Based on the cutting-edge technologies, such as Software-Defined Networking and Network Function Virtualization, a novel management framework upon the software-defined and Virtualized Network is proposed by EU H2020 SELFNET project. In the paper, the reference architecture of SELFNET, which is divided into Infrastructure Layer, Virtualized Network Layer, SON Control Layer, SON Autonomic Layer, NFV Orchestration and Management Layer, and Access Layer, will be presented.

https://journals.sagepub.com/doi/pdf/10.1155/2016/2897479

The SELFNET approach for autonomic management in an NFV/SDN networking paradigm

We report in this paper on research in progress related to network functions virtualization (NFV) and their use in network security. Our objective is to design and develop a virtual Security Appliance (vSA) capable of detecting various network attacks while offering an acceptable level of performance. In this document, we introduce the vSA under construction and show some testing results we have recently obtained.

http://ieeexplore.ieee.org/iel7/7390329/7394221/07394269.pdf

Virtual security appliances: the next generation security

The residential gateway (RGW) is a widely deployed device in the context of telecommunication services such as triple play and internet access. Designed to make the connection between the customer home and the operator infrastructure, it provides wired and/or wireless connectivity capabilities, also handling services such as Domain Name Service (DNS) proxying, routing, Network Address Translation (NAT) or firewalling, among others. Its increased complexity, together with other factors — such as device-related costs, or the increased reliance on RGWs for providing critical services — has prompted an interest in its virtualization, also motivated by the evolution of network and service-centric virtualization concepts. This paper presents an approach for the virtualization of the residential gateway (vRGW). It starts by giving an overview of the concept, explaining it and pointing out its benefits. It also explains the virtualization techniques and paradigms that have pushed this movement, namely software defined networking (SDN), network function virtualization (NFV), and service function chaining (SFC). Additionally, it describes the implementation of the vRGW architecture, including a description of its components and their integration.

Bruno Parreira

Papers

Toward a telco cloud environment for service functions

Cloud4NFV: A platform for Virtual Network Functions

The SELFNET approach for autonomic management in an NFV/SDN networking paradigm

Virtual security appliances: the next generation security

Building an NFV-based vRGW: Lessons learned