SDN: The Development, Adoption, and Trends

Jan 12, 2023ยท

5 min read


Traditional networks use hardware devices like routers, switches, and hubs to control the traffic in the network. Due to the growing business demands and the inability to scale and manage networks dynamically, Software-defined networking is taking control and gaining wider adoption. Software-defined networking provides a way to drive the traffic in a network using software applications in place of hardware devices used in the traditional model. SDNs use Open application programming interfaces to communicate with the hardware to direct network traffic. SDN was introduced to make networks programmable and dynamic. i.e., They can create and manage a virtual network and control hardware with software

In this article, you will learn what SDNs are, The Architecture of SDN, The several uses, cases, and benefits of using SDN, the various factors affecting the adoption of SDN in the industry, and the SDN trends to watch out for

Architecture of SDN


The SDN architecture is made up of three layers

  • The Application Layer

  • The Control Layer

  • The Infrastructure Layer

The Application Layer: This is the area that can be used to develop custom, innovative, or business applications by leveraging the information provided by the network i.e, statistics, topology, state, etc. It could be applications containing the business logic in a particular domain; It could be a firewall or a load balancer. These programs communicate their desired behavior to the control plane via the southbound interface.

The Control Layer: The Control layer, often referred to as the SDN Controller, connects the application layer to the infrastructure layer. The SDN Controller processes the requests from the application layer via the southbound interface and relays the information to the infrastructure layer via the northbound interface. It is usually referred to as the brain of software-defined networks.

The control layer is also connected to all the devices in the infrastructure layer and keeps track of relevant info about them i.e., topology, statistics, etc. The controller also converts information received from the application layer to low-level language that can be understood by the network devices to perform the desired action.

The Infrastructure Layer: This layer contains all the network devices, such as routers, switches, and hubs. They are mainly used for forwarding traffic to their respective destinations.

Benefits of SDNs

  • Efficient Network Management: SDN also gives you visibility into the networks and allows you to manage them networks.

  • Networking Innovations: With the Introduction of SDN-WAN, SDN can distribute traffic across wide area networks and determine the best possible path to route the traffic

  • Low operational costs: Traditional networks use hardware for redundancy to ensure high availability. SDN virtualizes the hardware and reduces the cost of setting up additional hardware

Use cases for SDN

  • Service provider networks: With SDN, service providers can now manage and provision networks dynamically. This also allows the providers to scale up or scale down the network on demand

  • **Simplifying Virtual Machine communications **: Managing the communications between large data center VMs can be tedious without software. SDN allows VMs to communicate without much concern for the underlying infrastructure

  • Orchestration of mobile network services: With NFV, mobile operators can now dynamically provision their networks. The NFV-SDN architecture allows companies to reduce the lead times a lot without increased performance over time.

  • Network Telemetry: With the introduction of In-band network telemetry (INT), network devices can be programmed to include the network states into packets as they traverse through networks. These states can be monitored to give insights into the network. INT is still an emerging technology, but it can provide qualitatively deeper insights into traffic patterns and the root causes of network failures.

Factors Affecting SDN Adoption

  • Reliability: The SDN Architecture uses a centralized controller to manage network devices. If the central controller fails, these can lead to availability issues as the traffic can no longer be routed to a node nearby like in the traditional network setup.

  • Interoperability: Another major factor affecting the adoption of SDN is interoperability. To transition from traditional networks to SDN, there have to be some parallel operations and protocols that make the SDN and traditional networks coexist. The protocols are meant to provide backward compatibility with existing traditional networks. Several industries like IETF, ETSI, and ONF are developing standards for SDN to make it backwards compatible and interoperable.

  • Control Plane Failure: If there is an attack on the control plane, this can fail the controller due to its centralized nature

SDN trends and future direction

  • Distributed controller design: The centralized nature of the SDN controller can be a significant problem. The ability to be able to design a distributed controller makes it more reliable and fault-tolerant

  • Dynamic and customized measurements: The SDN should also be designed to collect dynamic and customized measurements based on user requirements and demands. This will provide a more robust interface to obtain important measurement metrics from the plane

  • ** Forming the basis for 5G**: The evolution of 4G networks has resulted in a rapid change in the telecoms industry. Despite these changes, there is still a need for a more agile, speedier, and flexible network which is the foundation of the 5G network. With the programmable nature of SDN and the ability to create virtual networks, 5G may rely on SDN in the future. This can make SDN more flexible and widely accepted in the telecoms industry.


The software-defined network is gaining a lot of adoption due to the ability to create and manage virtual networks dynamically and program the networks. They improve the existing traditional networks, known for their rigid architecture. It provides more dynamism and flexibility. The software-defined network is an emerging technology. Several factors like scalability and interoperability affect its adoption in the industry today. Some initiatives like IETF, ETSI, and ONF are working to mitigate these issues and make it easy to adopt SDN.

In this article, you've learned about SDN, its benefits, use cases, factors affecting adoption, trends, and the future of SDN. You can get more information about SDN here.