Are you confused about the new and budding buzzwords in the network industry? Well, most network engineers often discuss the concepts of NFV and VNF but not without confusion. The concepts indeed are related but at the same time distinct. However, having a fair understanding of the underlying principles is a must.
We all can agree that the emergence of new applications is often the epicenter of new and dynamic challenges. However, networks should be capable of embracing new applications and technologies to meet the need for better speed, quality, higher bandwidth, and low latency connectivity to the end-users. Enterprises should appreciate the evolution of existing network architecture to realize a streamlined and innovative framework to support enhanced end-user experience and superior Quality of Service (QoS).
As enterprises plan to upgrade their networks, they will encounter new buzzwords, acronyms, or terminologies in the industry. These words sound similar and have correlated concepts however remain distinct. The buzzwords in the prevailing network landscape are the advanced technologies such as Network Function Virtualization (NFV), and its building modules, Virtual Network Functions (VNFs).
Networking professionals sometimes use the terms VNF, and NFV, interchangeably, which can be a source of confusion. However, if we refer to the NFV specifications the European Telecommunications Standards Institute (ETSI) sets forth, it becomes clear the two acronyms have related but distinct meanings. These technologies can realize flexible, agile, and low-cost network infrastructures.
Before understanding the difference between the two, let us begin with the basics.
What are NFV, VNF, and the NFV Framework?
Conventional networking depends on fixed hardware platforms. This type of traditional networking encompasses dedicated physical hardware utilized for network functionalities such as load balancers, firewalls, routers, and more. Due to vendor lock-in, conventional networking frameworks lack the flexibility and scalability to introduce new network functionalities. Traditional networking uses hardware appliances from specific vendors making it difficult to scale or update new functionalities.
The term Network Function (NF) typically refers to some component of a network infrastructure that provides a well-defined functional behavior, such as load balancer, intrusion detection, intrusion prevention, or routing.
Imagine eliminating those dedicated physical hardware from conventional networks and replacing them with software – that is the core of a Virtual Network Function (VNF). The concept of virtualization utilizes software to create an abstraction layer on the dedicated physical hardware. This results in a virtual computing system or Virtual Machine (VM) – a logical representation of a physical computer. As a result, enterprises can run multiple virtual computes, Operating Systems (OS), and applications on a shared and single physical server, realizing multiple logical or virtual servers.
NFV refers to the process of decoupling Network Functions (NFs) such as firewalls, load balancing, routing, and more from dedicated hardware to create a virtualized network that can run on general-purpose hardware, enabling a more cost-effective and flexible network. However, the VMs require a software or virtualization layer to interact and coordinate with the shared physical hardware. This virtualization layer is known as Hypervisor. The hypervisor enables the portability of VMs to different Hardware. NFV supports flexibility and agility by enabling services to be instantiated or deployed on demand. This is achieved by the modular architectural framework of NFV as shown in the image below:
- Network Functions Virtualization Infrastructure (NFVI): This represents the overall hardware and software components that build up the environment in which Virtual Network Functions (VNFs) are deployed. NFVI includes the virtualization layer (hypervisor) and physical and virtual storage, compute, and networking resources. NFVI manager or Virtualized Infrastructure Manager (VIM) is responsible for the overall NFVI management and allocation of VNF resources.
- Virtualized Network Function (VNF): implementation of NF that can be deployed on NFVI. VNF is a Virtual Functional Block (VFB) that provides the same functional behavior and interfaces as the equivalent Network Function.
The linkage of network functions to form service is called Service Function Chaining. Service Function Chaining includes a list of network services such as firewalls, Network Address Translation (NAT), Quality of Service (QoS), and more. These services are then joined together in the network to create a service chain. The lifecycle of VNFs is controlled and managed by VNF Managers (VNFM). - NFV Management and Orchestration (NFV-MANO) consists of 3 functional blocks:
- VIM – manages physical and virtual resources in a single domain, which includes management of computing, storage, network, and software resources.
- VNFM – manages each VNF instance. that is VNF lifecycle management e.g., instantiation. This also update, scaling, query, monitoring, fault diagnosis, healing, and termination of instances.
- NFV Orchestrator (NFVO) – combines one or more functions to create end-to-end services. NFVO is accountable for automating the deployment, operation, management, and coordination of VNFs and NFVI. The orchestration includes service as well as resource orchestration.
With the understanding of the basics of the concept of virtualization, let us now delve into the key differences between NFV and VNF as shown in the table below:
NFV vs VNF: Key Differences
| Features | NFV (Network Functions Virtualization) | VNF (Virtual Network Function) |
| Definition | The concept of virtualizing network services conventionally runs on dedicated hardware | Softwarized network functionality which is deployed on NFVI |
| Scope | Comprises the whole virtualization environment, including hardware, software, and orchestration modules | Indicates the specific individual NFs which are virtualized for a service |
| Components | Includes NFV Infrastructure (NFVI), NFV Management and Orchestration (MANO), and VNFs | VNF is one of the key components of the NFV framework |
| Functionality | Provides the architecture and environment to host and manage VNFs | Performs specific network tasks such as routing, firewalling, load balancing, etc. |
| Deployment | Involves setting up the virtualized infrastructure and management systems | Deployed within the NFV infrastructure to perform designated network functions. VNFs can be deployed independently or linked to create services |
| Management | Managed by NFV Management and Orchestration (MANO) systems. | Managed as part of the overall NFV system but can be individually controlled and configured by VNF managers. |
| Examples | NFVI platforms, orchestration software like OpenStack, MANO systems | Virtual routers, virtual firewalls, virtual load balancers. |
| Goal | To reduce costs, increase flexibility, and speed up the deployment of network services on demand. | To replace specific physical network functions with virtualized versions. |
| Evolution | Evolved as a concept to address the limitations of traditional hardware-based network functions. | Evolved from physical network appliances to virtual instances to leverage the benefits of NFV. |
| Standardization | Defined by standards bodies like ETSI | Typically designed to adhere to NFV standards but can be developed by various vendors. Interoperability is ensured by realizing seamless operations of VNFs from different vendors |
Though, virtualization brings in many benefits such as faster Time-to-Market (TTM) and cost-effective solutions, however, it also brings in many security concerns. Softwarization introduces more vulnerability to different kinds of threats. To address these threats, a holistic approach should be appreciated by enterprises to support an end-to-end security strategy covering both software as well as hardware layers.
Parting Thoughts
The concept of virtualization has gained traction in the IT sector with its capability of abstracting the underlying hardware and enabling multiple virtual instances to run on a single physical hardware platform. This in turn maximizes resource efficiency, flexibility, scalability, and low-cost deployments in IT infrastructure. Networking services are expected to be deployed at an accelerated pace, hence we are witnessing organizations making a beeline for implementing NFV frameworks within data centers. Moreover, NFV helps data centers or telecom networks to scale horizontally and vertically based on spikes in demand.
Calsoft, a Technology First company with more than 25 years of experience is one of the earliest contributors to virtualization technologies and has persistently followed the latest innovations and actively implemented them in customer projects for maximum business benefits since the past 2 decades. Calsoft has deep expertise in various NFV tools and technologies. Customers leverage our deep know-how and skills in building, testing, and deploying products that operate seamlessly in the diverse virtual ecosystem.