What Is Software-Defined Networking (SDN)? Definition, Architecture, and Applications – Spiceworks

Software-defined networking, commonly known as SDN, is defined as an architectural model for enterprise networks that enables them to be managed and optimized using a program-based approach. This article covers the definition, architecture, and applications of SDN.

What Is Software-Defined Networking (SDN)?

Software-defined networking, commonly shortened to SDN, is an architectural model for enterprise networks that enables them to be managed and optimized using a program-based approach.

How SDN Works

Companies leverage SDN to unlink traffic management and network configuration processes from the physical network infrastructure. SDNs allow open application programming interfaces (APIs) to exert more granular control over organizational networks remotely. The SDN architecture offers enhanced flexibility for coordination between network devices that serve specific functions. As a result, it is rapidly gaining popularity among companies across industry verticals.

A report by the International Data Corporation (IDC) pegs the SDN controller software market at $1.2 billion in 2018 and forecasts it to reach $2.8 billion by 2023. IDC also forecasts the SD-WAN market to increase from $1.3 billion in 2018 to $5.2 billion by 2023. Further, a 2020 survey on global networking trends by Cisco found that more than 6 out of every 10 organizations surveyed had deployed controller-based automation in their data centers, while nearly the same number had adopted SD-WAN technologies.

1. SDN makes a network programmable

A typical multinational corporation has thousands of devices that need to be programmed, monitored, and managed to ensure day-to-day business processes are carried out seamlessly. Traditional network operations involve configuring all these devices correctly, one by one, and then tracking the performance of every individual device. If this sounds overwhelming, that’s because it actually is. Traditional network management is a tedious process that leaves room for errors and security breaches. Even network management systems do not completely eliminate performance issues, network bottlenecks, and other shortcomings.

SDN works by using algorithms to automate device configuration and management. SDN can scale operations according to evolving network requirements, regardless of the number of devices connected to the network. IT administrators can leverage SDN capabilities to program the network according to traffic flow patterns or other factors. Network programmability enables enterprises to optimize business operations at a global scale. With SDN, it becomes easy to achieve a consistent network-wide state that is otherwise impossible when each component is configured individually without the context of its surroundings.

SDN replaces segmented network operations with an optimized, logically centralized network state. Networks are no longer dependent on their underlying limitations, and management consoles can now be operated through APIs to maintain a consistent level of overall network functionality, performance, and control.

In the case of traditional network architectures, the manual configuration of devices is the norm. Hardware-based configuration makes it difficult to locate and fix faults, giving a single device the potential of having a ‘domino effect’ on network performance.

A traditional business network is made up of three main architectural components:

• The ‘control’ component defines network topology and traffic routing.
• The ‘data’ component physically handles network traffic based on the configuration at the control level.
• The ‘management’ component handles network programming, supervision, and control processes.

2. Unlinks network architecture components

Traditional networks operate using integrated control and data components. Physical network devices and their associated protocols and software need to be configured to make any changes to the network. Devices operate independently from each other and are only partially aware of the logic used by the other devices on the same network. Naturally, only limited changes are possible to the system at large due to the bottleneck created by having to manage individual network devices.

SDN unlinks the control and data components, thereby centralizing control over the network logic and enabling IT personnel to select the programmable features that need to be moved from the device level to the controller or application server. Organizations can leverage centralized network logic and delinked controller operations to enjoy enhanced agility levels by automating, monitoring, extending, managing, maintaining, troubleshooting, provisioning, and deprovisioning network infrastructure with ease.

Thanks to SDN’s unlinked architecture model, applications can interact directly with the control layer and view the network state at the global level. This makes enterprise networks more scalable, flexible, and dynamic, thereby simplifying daily operations and allowing new business opportunities to be tested without having to worry about network architectural bottlenecks.

3. Enhances interoperability and openness

By enabling network programmability and unlinking network architecture components, SDN enhances vendor interoperability and network openness. This means traffic engineering, network integration, and inventory planning are easier. Device purchasing, commissioning, and management also become more straightforward. A more open, vendor-neutral enterprise network allows infrastructure investments into business and technical requirements to be optimized.

With remote work expected to remain popular in 2022, high data throughput, complicated network architectures, and ever-increasing demand for peak performance are expected to make traditional network management obsolete. This is because ‘static’ traditional networks are often inadequate for fulfilling the dynamic demands of the post-COVID-19 business landscape.

Today, a robust digital presence is vital for an organization to thrive in its industry. This calls for business network infrastructure that is flexible enough to scale according to the needs of fast-evolving computing environments, cutting-edge technologies, and dynamic business landscapes.

See More: What Is a Content Delivery Network (CDN)? Definition, Architecture, and Best Practices

Key Architectural Components of Software-Defined Networking

As outlined above, the SDN architecture decouples the control and data components of traditional networks. This allows companies to design networking and computing systems that use software-based technologies to optimize network hardware. Listed below are the key architectural components of SDN.

Key Architectural Components of Software Defined Networking

1. Application

The application component consists of programs that communicate with the controller using APIs. This component transmits data about desired network behavior and required resources to the controller, creating an overview of the network status in the process. The application layer also collects data from the controller layer to make the required decisions for fulfilling application goals.

Examples of applications include analytics, networking management, and business processes for data center operations. For instance, an analytics application can be configured to bolster network security by recognizing suspicious activity.

2. Controller

The controller component receives requirements and instructions from the application component and uses logic to process and relay them to the networking layer. This core element of the SDN architecture enables centralized supervision and management, enforcement of network policies, and automation across both virtual and physical network environments.

The controller is also responsible for collecting data about network health and status from the hardware layer and communicating this information to the application component. This allows the application component to create an abstract network overview that includes statistics and events.

3. Datapath

The datapath component allows users to supervise and exert control over the forwarding and processing of information by the hardware layer. This layer consists of a control-data-plane interface (CDPI) agent and a traffic-forwarding module and may also contain modules for network traffic processing.

A single network device can contain one or more SDN datapaths. Likewise, a single SDN datapath may be defined across multiple devices. This component can also help with processes such as management of shared hardware, logical to physical mapping, datapath slicing or virtualization, and compatibility with non-SDN networking.

4. Control to data-plane interface

The CDPI is used as an interface between the controller component and the datapath component. Its functions include allowing forwarding operations to be programmed, reporting network statistics, and notifying users of events of interest. Leading SDN solutions feature CDPI components that are open, interoperable, and vendor-neutral.

5. Northbound interface (NBI)

The NBI relays data between the controller component, the application component, and the policy layer. This component typically provides an abstract view of the network and enables the direct expression of network requirements and behavior, regardless of latitude (abstraction) and longitude (functionality).

6. Southbound interface (SBI)

The SBI relays data between the controller component and individual hardware units connected to the network, such as routers, access points, switches, and hardware firewalls. This component further classifies network concepts into more granular technical details meant for the lower layer of the architecture.

Simply put, SBIs enable network components to exchange data with lower-level components such as physical and virtual switches, routers, and nodes. For instance, routers rely on the SBI to view the network topology, decide network flow, and execute requests received from the NBI.

See More: What Is a Wide Area Network (WAN)? Definition, Types, Architecture, and Best Practices

Top 10 Applications of SDN in 2022

Software-defined networking allows networks to be more flexible, agile, and manageable. Here is a list of the top 10 applications of SDNs in 2022.

Applications of SDN

1. 5G

Wireless internet is rapidly gaining popularity for advanced applications such as the industrial internet of things (IIoT), smart cities, autonomous vehicles, fleet management, and smart farming. This calls for a standard that allows for throughput at previously unheard-of speeds. To fulfill this need, the rapidly evolving telecommunications industry is moving toward 5G as the latest standard for cellular connectivity.

Since 2019, 5G technology is being deployed in a phased manner across the globe. However, the full potential of this technology has not yet been explored. Creating 5G infrastructure that relies on SDN is predicted to create speedy, open-source networks that will be a game-changer for the global telecom industry. SDN-augmented 5G networks are expected to help businesses solve connectivity issues, bolster network security, minimize latency at a competitive price, and enhance the overall user experience.

2. Software-defined mobile network (SDMN)

A software-defined mobile network integrates SDN with cloud computing and network function virtualization principles in mobile networking environments. SDMN is expected to drive the change from rigid and incompatible legacy mobile networks to dynamic and scalable connectivity planes. This would be achieved by separating the data and control planes, a core tenet of SDN. Essentially, SDMN is expected to manifest as an extension of the SDN paradigm, incorporated with functionalities specific to mobile networks.

3. Internet-based networking (IBN)

As 2022 brings with it an exponential increase in new types of network-enabled devices, distributed applications, and their associated users, the complexity of connectivity architecture will increase. That is where intent-based networking comes in.

IBN is expected to transform manual, hardware-centric networks into controller-led environments that capture consumer intent and effectively distill it into policies that can be applied consistently across networks through automation. This would enable the network to monitor and tweak performance continuously to drive operations toward their desired outcomes.

IBN will manifest in the form of a closed-loop system that captures business intent and translates it into policies that the network can act on. These policies are then installed across both virtual and physical network infrastructure with the help of pan-network automation. Finally, machine learning and analytics are used to continuously monitor the network to verify the application of the appropriate intent and fulfill the desired business outcomes.

IBN will leverage SDN to implement a centralized control component for network activity. This will enable IT teams to view the whole network as an integrated entity. Holistic digital transformation would become far less challenging with controller-led networks across domains such as access, data centers, WAN, and cloud.

4. Software-defined wide area network (SD-WAN)

A software-defined wide area network is a form of virtual network architecture. Businesses leverage SD-WAN to securely connect applications and clients using any combination of LTE, MPLS, broadband internet, and other transport services. SD-WAN uses a centralized control component to securely direct traffic across the network to enhance application performance and user experience.

SD-WAN is managed by applying SDN principles. Decoupling the control and management components enables users to adopt commercially available leased lines to partially or completely replace MPLS lines, thereby minimizing costs. In fact, some estimates suggest that SD-WAN can be up to 2.5 times more economical than traditional wide area networks. Further, configuration and monitoring become easier as network administration is no longer tied to the hardware.

While SD-WAN has existed for some time, 2022 is expected to see relevant technologies packaged together in different ways. This is expected to drive new forms of network aggregation and management, as well as the dynamic sharing of network bandwidth across endpoints. As more businesses digitalize their operations to enhance agility and productivity, SD-WAN is expected to see an increase in popularity in the near future.

5. Software-defined local area network (SD-LAN)

A software-defined local area leverages SDN principles in data center environments. This network architecture aims to enhance the flexibility, adaptability, scale, and cost-effectiveness of both wireless and wired access networks.

Businesses from across industry verticals are expected to continue operating online in 2022. For them, ensuring the continuity of network operations is critical. SD-LAN rises to the challenge by delinking hardware- and software-based network layers, thus creating an architecture driven by application and policy.

SD-LAN is expected to see an increase in demand in 2022 for its ability to create centrally managed local area networks that are self-organizing, easy to use, and simple to scale and integrate. Expected applications of SD-LAN in the near future include wireless connectivity without the need for a physical controller and the implementation of effective cloud management systems.

6. Reliable group data delivery (RGDD)

Minimizing latency and ensuring continuity is critical for running a successful online enterprise in the post-COVID-19 business world. One way to bolster redundancy measures and fight lag is to leverage distributed applications that operate across data centers. These applications replicate and synchronize data for load balancing, fault resiliency, and bringing information closer to users. This requires dependable delivery of data from one server to multiple clients. This model of data delivery is known as reliable group data delivery.

An increasing number of enterprises are expected to leverage SDN switches for RGDD in 2022. This is because SDN enables the implementation of rules that allow information to be forwarded to multiple ports simultaneously. For instance, a centralized controller can be set up to create forwarding trees that ensure robust RGDD while accounting for network congestion and load status.

7. Agile operations

In the dynamic corporate landscape of 2022, one slip-up is all it would take to lose a high-value client to a competitor. As such, a cutting-edge operational methodology is the need of the hour.

SDN addresses this concern by simplifying network control, making corporate networks more agile. This is achieved through direct programmability resulting from the separation of forwarding functions. SDN also enhances organizational agility by extending the ability of a business to use dynamic load balancing. This helps better manage traffic flow according to fluctuations in need and usage.

Simply put, SDN minimizes latency and enhances overall network efficiency.

8. Simplified network setup

The trend of remote work is expected to continue well into 2022. This calls for simplification of network configuration operations for a wide array of circumstances, including new employee onboarding, new office setup, and extension of connectivity for clients.

SDN speeds up these processes by allowing users to write automated programs that can configure, optimize, and secure network resources as required. Further, this architecture helps simplify the designing and operation of networks by replacing vendor-specific protocols with open controllers.

SDN also enables the use of micro-segmentation to minimize network complexity. Finally, consistency is established across network architectures such as private cloud, public cloud, hybrid cloud, and multicloud with the help of SDN.

9. Cutting-edge corporate security

As companies recalculate their attack surfaces due to new vulnerabilities arising from remote work, cybersecurity is expected to be of utmost importance in 2022. SDN assists in bolstering the security posture of companies by offering centralized and granular control over network security. For instance, SDN allows network administrators to implement policies for different network segments and workload types from a central location.

Further use cases for SDN in cybersecurity include detecting and mitigating DDoS attacks, countering worm propagation, and preventing botnet attacks. SDN controllers can also be used to help implement moving target defense (MTD) algorithms, which periodically hide or change the key properties of networks to minimize their attack surface.

10. Optimized manufacturing

In the post-pandemic business world, a strong network defines any company, regardless of the industry. With the manufacturing sector picking up steam once again, there is an increasing need to connect manufacturers with suppliers and distributors to ensure smooth operations and maximize profitability. As a result, smart manufacturing and plant solutions have become more popular than ever.

SDN architecture helps connect numerous categories of endpoints in manufacturing plants, including IoT devices, sensors, and smart machines. The enhanced flexibility and efficient operability offered by SDN are bound to make it popular in the manufacturing space in 2022 and the years ahead.

See More: What Is Software-Defined Networking (SDN)? Definition, Architecture, and Applications

Takeaway

Software-defined networking has several applications in the post-pandemic corporate landscape. Its adaptability, ease of implementation, and automation-friendly architecture are expected to help SDN see heightened popularity in 2022 and beyond.

Further, with an ever-increasing number of companies adopting cloud platforms, SDN is expected to help enable the virtualization of cloud-enabled networking infrastructure. The responsiveness, automation capabilities, and cybersecurity applications of this emerging technology are only expected to increase in the near future.

SDN technology is the key for enterprises looking to solve networking challenges such as latency, geo-boundaries, and bottlenecks.

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