NFV vs. SDN: 10 Key Comparisons
Network functions virtualization and software-defined networking both use virtualization, but they differ in various ways.
- Network functions virtualization (NFV) and software-defined networking (SDN) both use virtualization — yet the two are fundamentally different in their architecture and the purpose they achieve.
- This article discusses ten ways in which NFV differs from SDN.
Table of Contents
What Is NFV?
Network functions virtualization (NFV) transforms network components and processes from hardware functions to software-driven functions that can be connected to create an end-to-end communication service.
Source: SDXCentral
Decoupling network functions from their corresponding patented hardware appliances and performing those operations instead as programs in virtual machines (VM) is the job of NFV. The various functions, such as virtual routing, traffic management, and firewalls, are called virtual network functions (VNFs).
When network operators virtualize their networks, they may save costs, reduce the time required to bring new or updated products to market, and enhance the scalability and adjustability of the resources accessible to services and applications. Other advantages include the following:
- Flexibility to switch vendors: When enterprises use virtual network functions (VNFs) deployed on commercial off-the-shelf (COTS) infrastructure, they avoid being restricted to in-house solutions.
- Savings and efficiency in resource use: The operation of a virtualized environment or any other infrastructure is more effective since more can be accomplished with fewer resources. This is made feasible because a single server can simultaneously execute multiple VNFs. As a result, lesser servers are required to perform the same tasks.
- Easier scaling: A company can upgrade its infrastructure using software whenever there is a variation in the network demand. There will be a marked reduction in the number of instances in which a business will need to physically upgrade its data and network centers.
- Faster time to market: NFV’s flexibility helps organizations adjust their operations more easily in response to evolving business requirements and emerging market opportunities. This means that the time it takes to bring a product to market is reduced.
Components of Network Functions Virtualization (NFV)
The network functions virtualization (NFV) framework has three main components:
1. Virtual network functions (VNF)
In addition to the physical hardware that makes up the networking infrastructure, virtualized network operations may be executed on one (or even more) virtual machines. Routers, switches, software-defined wide area networks (SD-WAN), firewalls, and an increasing variety of other network services are among the VNFs. These services are now offered as software by providers such as Cisco, Juniper Networks, and Palo Alto Networks.
VNFs are deployed on-demand using a network functions virtualization design that eliminates the implementation delays associated with conventional network hardware. Additionally, when VNFs are remotely deployed, there is no longer a requirement for on-site technical capabilities to be present. In multi-cloud and hybrid systems, virtual network functions (VNFs) provide the agility required to predict or adapt to evolving network performance or growth needs.
2. Network functions virtualization infrastructure (NVFI)
The virtual and physical network layers are enabled by the NVFI’s low-cost, standardized x86 software and hardware. This covers hypervisors, virtual machines, and administrators of virtual infrastructure. NVFI provides the computation, storage, network, and software resources over which VNFs are installed and maintained.
NFVI also offers the virtualization layer that resides on top of the hardware and isolates hardware resources so that they may be dynamically partitioned and provided to serve VNFs. This component is essential for constructing sophisticated, globally dispersed networks free of the geographical restrictions inherent in conventional network topologies.
3. Management, automation, and network orchestration (MANO)
The NFV management and network orchestration (MANO) framework was created by a working group of the European Telecommunications Standards Institute (ETSI). NFV MANO manages the assets (NFVI as well as VNFs) operating in a virtualized data center, from initialization to daily operations. In addition, it employs templates for common VNFs that enable architects to determine the most fitting NFVI deployment resources. Within the MANO component of NVF, there are:
- NFV orchestrator: It is responsible for VNF initialization, lifecycle administration, global resource planning, and request verification.
- VNF manager: It oversees the lifespan of VNF instances and offers coordination and adaption for NFVI.
- Virtual infrastructure manager (VIM): It maintains and controls the computing, storage, and network resources of the NFVI.
Adoption of NFV begins with the execution of network applications on COTS hardware and virtualization. Automated elasticity (the capacity to scale up and down dynamically) and centralized administration of infrastructures, assets, and applications comprise the subsequent phases.
See More: What Is MPLS (Multi-Protocol Label Switching)? Definition, Working, and Architecture
What Is SDN?
Software-defined networking (SDN) is a networking paradigm that directs network traffic using software-led controllers or application programming interfaces (APIs) to connect with underlying hardware infrastructure.
Source: Open Networking Foundation
SDN is distinct from conventional networks, which manage network traffic using specialized hardware devices (such as routers and switches). Software-defined networking may establish and operate a virtual network, as well as conventional hardware, through software. SDN differs from network virtualization as well.
Network functions virtualization (NFV) enables enterprises to segment distinct virtual networks inside a physical network or to connect devices on distinct physical networks to create a unified virtual network. On the other hand, software-defined networking (SDN) offers a new method of directing the route of data packets via a central server.
SDN offers several compelling benefits:
- Greater control: Rather than manually programming numerous vendor-specific hardware components, developers may simply design an open platform software-based controller to manage network traffic flow.
- Greater flexibility: Network administrators also have greater flexibility in selecting networking components because they can select a single protocol to connect with various hardware devices via a central controller.
- Easier customization: Administrators may update the network architecture in real-time by configuring network services and allocating virtual resources from a centralized location. This facilitates the optimization of data flow and application prioritization.
- Stronger security: It offers network-wide visibility and a more comprehensive overview of security concerns. Operators may define distinct zones for devices requiring varying degrees of network protection or quarantine compromised devices instantaneously.
Components of SDN
Similar to NFV, SDN consists of three separate components that reside in layers and connect using application programming interfaces (APIs). These elements include:
1. Applications
The application layer comprises commonly used network applications and functionalities in use by businesses. This might consist of intrusion detection systems, load balancing, as well as firewalls. A software-defined network substitutes specialized network appliances, like a load balancer or firewall, with an app that uses a controller to regulate data plane behavior.
2. Control
The control layer consists of the centralized SDN controller software, which serves as the network’s intelligence. This controller sits on a server and administers network-wide rules and traffic flows.
3. Infrastructure
The infrastructure layer consists of the network’s hardware switches. These switches route network activity to their respective destinations.
In a typical SDN situation, a packet is sent to a network switch. The switch’s proprietary firmware includes rules instructing the switch where to route the packet. The centralized controller sends the switch these packet-handling guidelines. The switch transmits all packets destined for the same destination via the same route and treats each packet identically.
A virtual overlay, which is a conceptually different network on top of a physical network, enables the SDN’s virtualization capabilities. End-to-end overlays allow users to isolate the network underneath and segregate network traffic. This micro-segmentation is particularly advantageous for service providers or administrators with multi-tenant public cloud and other cloud services since they can construct a distinct virtual network with tenant-specific regulations.
See More: What Is Software-Defined Networking (SDN)? Definition, Architecture, and Applications
NFV vs. SDN: Top 10 Comparisons
Service operators and enterprises can combine NFV and SDN technologies to boost their business agility and provide flexibility, scalability, automation, and provision of on-demand services. However, they have different concepts and target markets. Here are ten key differences between NFV and SDN technologies:
1. Target scope of the technology
Software-defined networking (SDN) mainly focuses on data centers, cloud, and campus environments. In campus environments, SDN provides a platform to enforce adaptable policies across wired and wireless infrastructures. It offers more programmability opportunities, automation, and network control. It also provides enterprises with a platform to build highly scalable and flexible networks.
Network functions virtualization (NFV) targets service providers or operators. NFV allows telecom service providers to unlink network functionalities, such as routing decisions from local devices and implement them on remote servers and clouds. Implementing NFV enables service providers to reduce CAPEX, OPEX, and power consumption by consolidating equipment. Thus, it allows them to increase their profitability by reducing their operational costs.
2. Underlying concept
SDN controls networks by separating the control plane from the forwarding plane by centralizing control and enabling network programmability. Administrators and architects can use software to configure and manage network functions through a centralized point. This technique leads to the creation of dynamic, highly scalable, and agile networks that use the virtualized infrastructures of data centers to meet the expectations of the evolving business landscape.
NFV separates virtual network functions (VNF) such as firewalls, load balancing, and policy management from dedicated proprietary hardware and shifts them to virtual servers. Moving VNF to virtual servers allows network operators to maintain the network performance while eliminating the need for using costly hardware and paves the way for purchasing affordable switches, servers, and databases to operate virtual machines. Using fewer physical servers reduces costs and simplifies network management and maintenance.
3. Protocol used
OpenFlow is the standard communication protocol used in SDN. It was developed in 2008 by Stanford University researchers before being adopted by Google in 2012. The Open Networking Foundation (ONF) currently manages it. This southbound protocol defines the communication between the SDN controller and a network device such as a switch. The OpenFlow protocol can only be established between a controller and a switch in a network.
This protocol ensures that data packets between switches are secure and not susceptible to denial of service attacks. After the SDN controller collects data from applications, it converts it into flow entries, which are then sent to the switch through the OpenFlow protocol. This protocol can also be used in network management to monitor port and switch statistics.
On the other hand, NFV has no established communication protocol.
4. Groups responsible for formalization
The Open Networking Foundation (ONF) is a user-driven nonprofit organization formed in 2011 by a consortium of different companies, Deutsche Telekom, Facebook, Google, Verizon, Microsoft, and Yahoo! ONF aims to promote the advancement adoption of SDN through open standards development.
The ONF believes that adopting SDN will give network administrators unprecedented automation, programmability, and control while reducing operational costs, enabling them to integrate the best technology in their networks. The significant flagship contribution of ONF is the introduction of the first SDN standard known as the OpenFlow standard, which enables the interaction of the SDN controller and the forwarding plane, such as a router or switch, in an SDN environment.
The European Telecommunication Standards Institute Industry Specification Group for Network Functions Virtualization (ETSI ISG NFV) was formed in 2012 to develop the required standards for NFV transformation incorporating the latest technologies, testing multi-vendor environments and sharing their experiences of NFV implementation. It was formed by AT&T, BT, Deutsche Telekom, Orange, Telecom Italia, Telefonica, and Verizon.
5. Supporters of the initiative
The SDN project is supported by several enterprise networking software and network hardware vendors. SDN allows business enterprises to transition from using expensive and proprietary firmware-based network layer devices such as routers that support data traffic forwarding and network control.
Enterprises can then adopt software-based control SDN by using the OpenFlow protocols to manage and forward data traffic through virtual switches in data centers. This transition allows enterprises to adopt SDN technologies that are cost-effective, faster, and agile in their business policies.
The prominent supporters of the NFV initiative are telecom service providers and network operators. NFV allows network operators to adopt a model similar to that of the web and enterprise IT. Thus, the service providers can switch from using expensive proprietary hardware to deliver telecom services to software running on commercial off-the-shelf servers located in data centers, network nodes, or end-user premises.
This transition would lead to substantial operational cost savings and allow service providers to redesign their business models from engineering-led to data-centric businesses.
See More: What Is MPLS (Multi-Protocol Label Switching)? Definition, Working, and Architecture
6. Business drivers and adopters
The main business initiator for SDN is corporate IT. As the corporate world tries to keep up with emerging technologies, it must incorporate the best technology practices. The corporate IT sector faces networking challenges that require their networks to adjust automatically and respond dynamically based on their business policies.
SDN provides solutions to these networking challenges. Examples of SDN solutions include augmented automation, centralized networking control, improved network security, and reduced operating costs.
The main business initiator for NFV is service providers or telecom network operators. Over the past years, substantial operational costs have significantly hindered service providers and telecom network operators. Service providers must use large and expensive proprietary hardware to deliver telecom services; however, after incorporating NFV, all that is set to change. The NFV concept entails replacing the dedicated proprietary hardware with the software on virtual servers. This transition leads to improved resource allocations.
7. Location where the applications run
Most SDN applications can run on industry-standard servers or switches. SDN switches simplify network management, operation, and management by separating network control and forward functions from the individual switches and placing them in a centralized SDN controller. The centralized SDN controller appears as a single logical switch to the applications, thus simplifying operations.
Additionally, the SDN controller eliminates the need for several highly intelligent switches across the network, as organizations can use commodity switches known as SDN white box switches. SDN applications can also run on industry-standard servers. The servers have three major SDN components: a network controller, software load balancer, and gateway. These components ensure that applications are highly and securely available and with evenly distributed customer network traffic.
However, most applications in NFV can only run on industry-standard servers only. The servers host the virtual machines that provide network functions such as routing decisions and firewalls.
8. Benefits of the technology
SDN promises greater reliability through network automation. Through automation, networks can be configured automatically to minimize the need for long manual work. SDN ensures more efficient network management by offering administrators real-time statistics on the network performance to determine when to optimize the network.
Enterprises can also enjoy substantial cost savings by implementing SDN in their networks. SDN offers a reliable path for enterprises to automatically reroute their networks during outages in specific areas without additional equipment such as routers, switches, and circuits; thus, it is cost-effective.
On the other hand, service providers implementing NFV in their networks experience a reduction in capital expenditures and operating expenses (CAPEX/OPEX). The reduced costs result from deploying software-based functions on virtual servers, eliminating the need to maintain expensive proprietary hardware. NFV also allows telecom operators to dynamically allocate available resources as needed, thus leading to improved resource utilization.
9. Main applications
SDN can be applied in networking and cloud orchestration. SDN orchestration refers to configuring automated actions in a network to coordinate the required hardware and software elements when providing support to applications and services.
SDN orchestration is deployed in enterprises to help them connect their diverse customers, connect Internet of Things (IoT) devices, manage network resources and applications in data centers and clouds, and secure all elements against threats.
NFV can be used in a broader range of applications, such as network slicing, security, and mobile computing. The idea of centralized control mechanisms and equally distributed enforcement makes NFV attractive. It is also set to play a significant role in network slicing, especially with the increasing popularity and rollout of 5G networks.
10. Architecture of the technology
The SDN architecture layer consists of three layers. The application layer consists of programs that programmatically communicate network requirements to the SDN controller. But these applications do not mirror any function of the core network.
The control layer processes instructions and requirements sent by the application layer and sends them to the networking components. The infrastructure layer consists of networking hardware devices that control the network’s data forwarding and processing abilities. These layers communicate through application programming interfaces (APIs).
As discussed, the NVF architecture consists of the virtualized network functions (VNFs), network functions virtualization infrastructure (NFVi), and management, automation, and network orchestration (MANO) layers. The VNF layer comprises software applications that deliver network functions, NFVi consists of infrastructure components, and MANO provides the management framework.
See More: What Is a Virtual Private Network(VPN)? Definition, Components, Types, Functions, and Best Practices
Takeaway
NFV and SDN both utilize software components, but the two are fundamentally different. NFV converts network processes themselves into software applications, while SDN virtualizes the management of networks so you can gain from features like application-based traffic prioritization. Organizations need not choose between NFV and SDN since both can coexist in the same environment.
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