Software-defined networking (SDN) and its complementary technology network functions virtualisation (NFV) are helping enterprises globally in improving the agility, automation capability, flexibility and interoperability of their network designs. SDN helps create a virtualised network overlay, which allows the underlying network to quickly respond to network changes and forward traffic efficiently. Meanwhile, NFV allows the transition of traditional network functions such as load balancers, firewalls, subscriber policy management and mobile radio access network from a physical hardware set-up to a virtual network.

SDN and NFV deployments have started altering operational and service dynamics for telecom operators across the world. Operators are increasingly using SDN and NFV to manage and provision network services from a centralised location, thereby enabling faster and cost efficient delivery of on-demand applications with minimal disruption. Besides, the bandwidth flexibility, programmability and automation capabilities of SDN and NFV are helping service providers monetise their range of services linked to internet of things (IoT) and cloud infrastructure.

Global market size and growth

The global SDN market is expected to grow from $8.8 billion in 2018 to $28.9 billion by 2023, at a compound annual growth rate (CAGR) of 26.8 per cent. This will be driven by the burgeoning demand for data centre services in enterprises. Data centres are the major end users of the SDN framework. SDN helps in addressing congestion-related issues in data centres as it provides visibility and control of the traffic in a network. The SDN market is expected to witness the maximum growth in North America as the region is leading in terms of adoption of next-generation technologies such as cloud computing, network functions virtualisation (NFV), mobility services and bring-your-own-device.

As per industry estimates, the size of the NFV market will reach $70 billion by 2024 driven by the growing adoption of mobility services in enterprise IT infrastructures, low telecom carrier costs, and commercialisation of 5G technology. Moreover, enterprises are expected to deploy cloud-based NFV solutions to scale their networking infrastructure in order to meet the increased workloads and reduce the cost incurred in procuring additional hardware appliances for supporting new network services. The adoption of NFV will also enhance enterprises’ ability to deliver better network function performance with smaller data centre rack spaces, and limited power and cooling requirements.

So far, the hardware segment has held the majority share in the global NFV market due to the large-scale adoption of NFV servers for virtualising diverse network functions such as firewalls, network address translation, routing and internet protocol  (IP) security. However, going forward, the software segment is expected to lead the NFV market growth due to the extensive deployment of NFV management and network orchestration (MANO) platforms as well as virtual network function software applications for virtualising a diverse set of network functions. The manufacturing sector is expected to be the largest adopter of NFV owing to the large-scale implementation of industrial IoT technology. In the manufacturing sector, NFV uptake is expected to register a CAGR of 50 per cent between 2018 and 2024.

Indian operators to ramp up investments

The Indian SDN and NFV market has witnessed subdued growth owing to the lack of well-developed standards for these solutions. However, the upsurge in data consumption is compelling telecom operators to adopt SDN and NFV in a big way. Operators are turning towards SDN and NFV to provide the highest level of customer experience and, at the same time, keep operational costs in check.

At present, Bharti Airtel is using SDN/NFV to offer music and on-demand video services. It had earlier signed a contract with software major Google to use the latter’s SDN-based platform for running network services in a virtualised environment. The platform will allow Airtel to adapt to new services and traffic patterns effectively and efficiently. Meanwhile, Reliance Jio Infocomm Limited has joined the open network automation platform as a platinum member to work with open source communities to build Jio MANO, its own management and network orchestration software, which is in pre-production, and develop its own SDN controller. Vodafone Idea Limited is also running trials of SDN and NFV, and plans to soon deploy these technologies commercially. The operator is also working towards simplifying and upgrading its data centre architecture in order to host cloud-native apps related to network and the IT domain.

Enabling role of SDN and NFV in 5G roll-outs

SDN and NFV are expected to accelerate 5G deployment by addressing the major functional needs of 5G networks. The high flexibility and adaptability of SDN and NFV solutions will help meet the throughput and processing requirements of different 5G services. SDN and NFV will also help operators scale easily to support 5G expansion and configure their networks to allow a seamless interaction among different services inside the core network.

NFV will play a critical role in the deployment of 5G services on third-party hosting infrastructures. Besides, it will allow a 5G physical network to be divided into various virtual networks capable of supporting multiple radio access networks across different customer segments and environments. Meanwhile, SDN can be used to provide an overall framework to enable 5G to function across a normalised control plane. This will help manage network behaviour through application program interfaces and provide services through the network. In addition, SDN can provide better data traffic management on the 5G network by determining optimal data flows in real time, minimising network bandwidth and boosting latency. SDN will also assist in efficient performance monitoring of 5G networks.

Therefore, it is imperative for telecom operators to work with global co-location and interconnection providers offering carrier-grade infrastructure and a wide range of easy-to-deploy SDN and NFV solutions in order to realise the full potential of 5G services.

Growing popularity of SD-WAN

Over the past two to three years, wide area network (SD-WAN) has emerged as the most popular application of SDN technology. SD-WAN is a virtual WAN architecture that allows enterprises to leverage any combination of transport services including multiprotocol label switching, long-term evolution and broadband internet services to securely connect users to applications.

The traditional WANs based on conventional routers are not cloud friendly and typically require backhauling of all traffic including the traffic that is routed over the cloud from branch offices to a hub or a headquarter data centre. The delay caused by backhaul impairs the application performance resulting in the poor user experience and productivity loss. SD-WAN technology uses a centralised control function to securely and intelligently direct traffic across WAN, thereby increasing application performance, enhancing user experience and reducing IT-related costs.

The two key SD-WAN capabilities for enterprises are centralised orchestration and zero-touch provisioning (ZTP). Centralised orchestration helps enterprises centralise the configuration, application performance and security policies of WAN. Meanwhile, with ZTP, configurations and policies are programmed once and pushed to all branch locations without having to manually program each device. It therefore eliminates the need to send specialised IT resources to branch locations whenever a new application is added or a policy change is introduced. ZTP also reduces human errors, resulting in more consistent policies across a firm.

For enterprises globally, SD-WAN will usher in a new era of flexibility. SD-WAN handles traffic based on priority, quality of service and security requirements. It continuously monitors applications and WAN transport resources, and can quickly adapt to the changing network conditions to maintain the highest application performance and availability. Advanced SD-WAN delivers the highest levels of experience, even if a transport service experiences an outage. This improves business productivity and end-user satisfaction. Owing to its flexible nature, SD-WAN helps reduce the need for over-provisioning, thus bringing down overall WAN expenses. According to research firm Gartner, up to 25 per cent of WAN users will manage their network with the help of SDN solutions within the next two years. Meanwhile, revenue from SD-WAN solutions is growing at 59 per cent annually and SD-WAN is expected to become a $1.3 billion market by 2020.

Key challenges

While the shift towards SDN and NFV is expected to help enterprises and service operators create a more agile, virtualised and automated network infrastructure, it is likely to bring in a new set of challenges for them. For one, until the migration to all-virtual networks is completed, enterprises and service providers will have to deal with a combination of legacy networks and new virtualised networks to manage a multivendor environment. Operators will have to look for orchestration vendors that can function as service integrators, and ensure end-to-end integration and management of the ecosystem.

Further, an enterprise cannot fully leverage SDN and NFV unless its operations support systems and business support systems are aligned with the new technologies. On the technology front, the lack of a mature technology, consensus on multiple open source standardisation initiatives and proven business cases also pose significant challenges.

In order to migrate to SDN- and NFV-driven networks, operators and enterprises will have to modify their network architectures, overhaul their business models and make organisational changes. These technologies require a fundamental change in the way networks are controlled, and a completely different approach to network and employee management.

The way forward

SDN and NFV encompass various solutions aimed at making networks agile and flexible. These technologies provide myriad benefits to telecom operators, enterprises and data centres. Besides addressing the explosive increase in mobile data traffic, SDN and NFV can help service providers limit their capex and opex requirements by reducing their dependence on expensive proprietary hardware platforms. Globally, the major service providers are scaling up investments in SDN and NFV, and it is about time that Indian operators step up their SDN and NFV deployment as well. This will facilitate the roll-out of 5G services, which require a dynamic, flexible, programmable and virtual network architecture in order to ensure a steady flow of revenue and sustainability for service providers.

Rise of Open Source: Deployment across different layers of 5G networks

With the emergence of network softwarisation, open source software is going to become critical to 5G and play an important role in the development of 5G networks. Open source projects have a global developer community for solving technical challenges and expanding access to technical capabilities. The community model of open source development identifies and responds to user needs more rapidly than perhaps the traditional standards. Open source could help operators find interoperable solutions, encourage innovation, improve quality and security, and contribute to the community. The open source approach also helps vendors free up resources to pursue value-added products/services, improve quality and security, and contribute to the community.

The following aspects need to be considered when determining the applicability of open source across different layers of a 5G network…

5G infrastructure

In order to meet the bandwidth requirements of a  large number of devices, it is essential to transform the network so as to scale it up and make it agile while reducing cost. Network disaggregation with separation of user and control plane, separating the network operating system from the underlying hardware, and the use of general-purpose processing platforms is the key to creating networks that are massively scalable, agile and inexpensive.

Disaggregated hardware provides high performance at lower costs via approaches such as specialisation of tasks (for example, servers designed for packet processing) or conformance to a common standard for commoditisation.

5G radio network

5G brings a diverse set of requirements and use cases, and requires an entirely new Radio Access Networks (RAN) architecture that is flexible, modular and supports open interfaces. The new RAN architecture needs to be operationally efficient. It should be able to adapt to the diverse requirements of 5G.

5G core

The core network is a critical component, so it needs to be robust, highly resilient and high performing. 3GPP’s service-based architecture has standardised the network functions, their procedures and the inclusion of NF sub-modules. Standards also define the application program interface (APIs) to be used by providing data models, protocols and formats. However, a lot of innovation and research is happening in the open source community and by vendors so as to address specific problem areas or find new ways of implementing specific interfaces.

Management and control

Network function virtualisation (NFV) and software-defined network (SDN) are the key technologies required for improving the quality of service (QoS) with reduced capex, opex and energy consumption. RAN virtualisation is a key enabler for 5G, providing flexibility, scalability and most importantly optimum resource usage. Running software payloads on virtual machines provisioned on general-purpose processing platforms enables optimum usage of underlying network capacity and resources among deployments with varied traffic utilisation. Virtualisation benefits from low-cost, off-the-shelf hardware, while gaining greater agility in network management, service creation and provisioning.

The European Telecommunications Standards Institute  aims to address the challenge of moving away from proprietary hardware in NFV by converging the telco and IT networks. It applies standard IT virtualisation to consolidate network equipment types such as standard high-volume servers, switches and storage. NFV is complementary to SDN and can be easily used to manage NFV deployments.

Some of the areas to be considered as applicable for open source in the management and control domain are:

  • Orchestration of network services to provide expected agility in telecom networks requires a way to define these services down to their atomic nature, physical and virtual resources.
  • Network automation enables automation by programmatically configuring and provisioning network connections. With disaggregated software, separate control and user planes, and distributed network functions, there is a need to automate the means of managing the control of the NFV infrastructure and also the virtual network functions (VNFs) running on that infrastructure. This will transform the network by making it operationally efficient and reduce opex. The key to efficient network automation is maximum openness without which integration is not possible. In the absence of standard bodies that focus on network automation, there is a need for adopting an open source approach. Some initiatives in this area that should be considered as applicable for 5G are ONAP, ZSM (zero touch network and service management), and experiential network intelligence.
  • Analytics will also be important for network automation as it allows closed-loop feedback for effective service assurance. This will enable the network to self-heal, self-optimise and self-organise, bringing operational efficiency in network management. Open source communities have significantly contributed to big data analytics projects that utilise many open source stacks. With the growing number of devices and data explosion in 5G networks, real-time analytics of disparate data will be necessary.
  • DevOps is a software engineering culture and practice that aims at unifying software development and software operation. The cloud-native approach is fundamental to 5G network functions/services, and allows vendors and service providers to deploy DevOps methods to automate the process of building, validating and deploying workloads in NFV environments. This enables service agility. Any open source efforts in this DevOps area are applicable for 5G.
  • There are thousands of software and stress test tools, and a few hundred network test and simulation tools. By comparison, there are few such tools for testing telecom-specific protocols.

Convergence of telecom and IT with open source

Web-scale internet companies have adopted disaggregation, deploying thousands of white box servers and switches running modern operating systems, open source software and automation at an unprecedented scale. This has allowed them to transform traditional IT data centre infrastructure into a hyper-scalable architecture, enabling them to deploy services more efficiently and cost effectively.

Web-scale IT is characterised by the use of open source software and commodity hardware to create infrastructure that can be completely controlled by software. These cloud computing principles being adopted in technologies such as NFV and SDN will benefit the telecom industry in the 5G era. Web-scale architectures are already agile, born on the cloud and built on the new, faster principles that need to be adopted in order to build an agile mobile network. The web-scale delivery model is based on open source software, which supports continuous design, build, deploy and test. DevOps has made it possible for companies to develop infrastructure that responds quickly to change while remaining stable and reliable.

Open source software related to artificial intelligence, machine learning tools and real-time data ingestion developed by the IT industry will be applicable to the 5G world, where network automation will be critical for operational efficiency.

Unlike previous network generations, 5G is expected to support a diverse set of use cases and be agile in service delivery and efficient in network operations. Therefore, it is important to adopt the principles of web-scale internet companies. NFV, SDN and automation are key enablers of 5G. Hence, any open source project benefiting from the contribution of development done by web-scale companies should be considered as applicable.

Open source design

5G networks need to support diverse requirements and services. Thus, their design should support disaggregated network functions that are modular, flexible, and support extensible open interfaces and are cloud-native in all aspects. Open source must adopt and demonstrate these design principles in order to successfully integrate them into telecom infrastructure and applications. These should be important criteria while determining the applicability of certain open source projects for 5G.


Open source has been the key to recent advancements in high performance and flexible packet processing, which is important for 5G use case and services. There are already a number of open source projects that are well into their product cycles, and more will be emerging as 5G network deployments begin. Infrastructure management and control (automation, orchestration, analytics, testing) are the key areas that, if open sourced, could benefit mobile operators the most in their 5G deployments.

Operators have different strategies for evolving their networks to 5G and each operator environment is different. There is no single open source effort that meets the needs of all operators and network evolution cannot be prescribed to apply to all deployments. Initial 5G deployments are expected to encounter the interoperability challenges that 3G and 4G faced. However, 5G system architecture gives mobile operators more openness than previous generations. Operators and original equipment manufacturers may leverage open source principles in order to stay or become competitive in the marketplace.

Based on the white paper, “The Status of Open Source for 5G”, by 5G Americas