Virtualizing Network Functions in Software-Defined Networks

Virtualizing Network Functions in Software-Defined Networks

Vishal Kaushik (University of Petroleum and Energy Studies, India), Ajay Sharma (SRM University - Haryana, India) and Ravi Tomar (University of Petroleum and Energy Studies, India)
DOI: 10.4018/978-1-5225-3640-6.ch002
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Software-defined networking (SDN) is an emerging network architecture that facilitates the network administrator to control and manage network behavior dynamically. Different from traditional networks, software-defined networks support dynamic and scalable computing. The dynamic behavior is achieved by decoupling or disassociating the system. The swing of control from tightly bound individual networks to assessable computing devices enables infrastructure abstraction. Due to the abstraction, the network can be considered as a logical or virtual entity. In this chapter, relation between network function virtualization (NFV) and software-defined networking (SDN) has been outlined. This chapter focuses on describing the pros and cons of NFV technologies. network functions virtualization (NFV) was founded under the work of the European Telecommunications Standards Institute (ETSI).
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CDN: Content Delivery Network

The term Network Function Virtualization (NFV) was initially announced in October 2012. A consortium formed by some leading telecommunication companies such as AT&T, BT, China Mobile, and Deutsche Telekom introduced the NFV Call to the Active document (Chiosi et al., 2013). Another new committee established under the European Telecommunications Standards Institute (ETSI) focused on improving the speed and operating standards. They worked on constructing the NFV standards and their work results as a white paper on Software-defined Network (SDN) and is entitled as “Network Functions Virtualization (Simone et al., 2015). This had been published by a specification group in Darmstadt, Germany. NFV, being a part of that work e ETSI and comprised of representatives from European telecommunication industry from Europe. They produced a standard terminology definition & use guiding the vendors and operators to facilitate better management and implementation of NFV. Herewith, a traditional standard for stability, quality and protocol adherence came into existence in a more refined manner (Borcoci, 2015).

Understanding Relationship Between NFV and SDN

The construction of NVF revolves around the key features of SDNs such as control/data plane separation, virtualization, SDN controllers, and data center concept. The NVF and SDF shares similar goals but both have different working strategies.

The statement that “Due to recent network focused advancements in PC hardware, any service that is able to be delivered on proprietary, application-specific hardware should be able to be done on a virtual machine” summarizes the entire evolution of Network Function Virtualization. Nowadays, a number of network devices viz. Routers, Firewalls, Load Balancers and so on are running virtualized on commodity hardware (Noble, 2017).

With a clear objective of reducing equipment costs and decreasing time to market, NFV achieves elasticity and scalability along with strong ecosystem. The SDN also breaks the bond that relates the control/application software with the hardware. Both the architectures- NFV and SDN need optimization at carrier scale of the dynamic cloud environment (Benington, 2014).

For achieving greater agility, SDN and NFV aim to control automation and virtualization. Whereas optimizing the deployment of network functions (such as DNS, load balancers, firewalls etc.) was the main intention of NFV. The physical as well as the virtual layers that enable to interconnect virtual network function endpoints require large-scale dynamic network connectivity to be deployed (Nunes et al., 2014)

Figure 1.

SDN and NFV Relationship


Network Function Virtualization finds its roots in several previously described network operations problems, especially the implications of bundling services by network equipment manufacturers within their platform Operating Systems. NFV can also be applied to appliance vendors in a way that does not take advantage of the processing scale/innovation seen by many customers in their data centers.

Different from NFV, SDN involves different control modules, interfaces and the applications that are mandatory for its proper working. NFV just needs shifting of network applications based on dedicated hardware to virtual containers on Commercial-off-the-shelf (COTS) hardware. More illustratively, SDN is present whereas NFV is future (Matias et al., 2015).

NFV unites forwarding devices and middle-boxes shaping a common control framework. Use of NFV enables network policies to get implemented by the operators irrespective of the placements viz. placement of functions etc. and also it provisions no need of thinking about the steering which includes how to route traffic through these functions. The network services are deployed on generic x86 hardware facilitating flexible resource allocation, scale-out architectures, bare metals or virtual machines etc. (Kolias, 2014; McKeown et al., 2008).

The network services and functions can be further categorized into three major categories- simple virtualized services, service chaining, and services virtualization or platform virtualization.

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