There are many factors to be considered when evaluating Software Defined Networking (SDN) technologies. Whilst vendors may race to provide SDN solutions, the next generation network continues to be hotly debated as the technology brings a number of opportunities and challenges to carriers and enterprises alike.
SDN has the potential to revolutionise networks by providing an unmatched level of agility, innovation and automation that reduces the complexity and cost of network administration dramatically. The implementation of SDN comes into question largely when discussing the protocols, APIs and standards that should be leveraged to deploy the solution.
For example, open and feature rich Northbound APIs (north-bound application programming interfaces), which are used to communicate between the SDN Controller and the services and applications running over the network, will play a large role in delivering value in the years ahead. However, SDN’s real value is in aligning the business application with the network while providing automation, so that the abstraction and programmability capabilities of SDN can help the business become more agile and foster innovation.
Research firm Infonetics recently completed a survey regarding the technology. The firm found customer perspective regarding SDN ranged widely but focused on a few key notions:
- Network planners design architectures for one primary reason: to support applications and communications. Thus their investment in network equipment corresponds directly to what the network needs to support, regardless of whether or not it is SDN-based.
- Network solutions require the basics first, and that is speed, availability, security, resiliency and redundancy. Before SDN protocols can even be considered, these network properties must first be satisfied.
- Efficiency from virtualisation is persuasive and the prospects of reducing costs and the amount of equipment deployed to satisfy application requirements will make SDN “unstoppable”.
Due to the vast array of software and protocols, SDN has no single architecture that caters to all needs. It has become necessary that the SDN market fragments to align with the demands of enterprise, cloud and data centre providers as well as telecoms operators. The SDN market must also cater for specialised situations including High Performance Computing (HPC) and research markets pertaining to universities and governments.
Over the lifespan of what we now term SDN, these ‘pure’ SDN architectures have been increasingly improved by a shift in approach to an application-centric focus that targets integration of applications rather than the development of underlying technologies. As a result, various overlay and virtual switch-centric solutions for data centres have been unveiled in the market recently.
When we discuss APIs, a whole new dimension of SDN should be touched upon, one that most network operators want to understand to allow SDN to be personalised for their own requirements. The focus must turn to open APIs embedded into the network nodes but also in the centralised management and control solutions, which is key for the SDN deployment.
The application environment can then tap directly into the infrastructure via those APIs, whereby a key differentiator is the level of abstraction that the central management and control solution can provide towards those applications. The level of abstraction depends on what an organisation needs to be accomplished through the technology. If the organisation only desires to expose all of the capabilities of the existing network devices and topology to a networking administrator simply for access, then abstraction may not be needed at all, but there would be no benefit to this.
Change Is Coming
The full potential of SDN is truly about driving organisational change and different processes — where resource control is delegated to lines of business within the enterprise that are outside of the network domain, eventually even outside of IT.
Such a scenario, though difficult to achieve, creates real agility. The knowledge about networking in those groups may be non-existent, and they should not need to care about it – it just has to work. However, even inside IT groups, if the administrator deploys applications and workloads in an automated and orchestrated fashion on the network — the typical SDN use case in the data centre – the question still arises: What does the administrator need to know about the network? How much does the application need to know about the network that it gets deployed on?
The usability of a SDN solution, the adoption in the enterprise, and also the success of those vendors who provide SDN solutions to the enterprise will depend on how well they strike that balance. Interestingly, in 2013, the industry saw elements of software abstraction take shape with various vendor specific implementations, but also with OpenStack – a cloud orchestration industry-sourced platform.
OpenStack, in conjunction with the Ethernet network, can enable management and orchestration service provisioning for the large Enterprise Data Centre and Cloud Service Provider markets. OpenStack orchestrates computing and storage configurations with the network via a software plugin that allows the OpenStack platform to access the network and its abstraction layer using open APIs, where Simple Object Access Protocol (SOAP) and RESTful over Extensible Markup Language (XML) are often used.
This multi-faceted approach to building and implementing SDN allows a complementary mix of industry and customer perspectives, enabling many more variants of SDN technologies. The ultimate goal for organisations is to seek an SDN solution that will fit their needs and that will integrate with the underlying network, to provision and orchestrate resources based on dynamic policies, and allow further application level visibility to enable even more granular dynamic policies.
Businesses that wish to take advantage of big data require a personalised SDN that can cater to their needs. Big Data applications tend to have low tolerance for latency and have varied traffic patterns. These network characteristics tend to increase the complexity and cost of provisioning Big Data networks. An application-aware network provides feedback to the SDN management system that can optimise the provisioning of resources for big data applications.
Each and every architectural approach fits a specific market segment and set of requirements best, so organisations need to assess their requirements and find the right architectural fit before implementing SDN.
Several of these new SDN solutions are deployable today. They can scale up and interoperate, as they rely on existing protocols, thus providing a smooth migration and integration into existing, heterogeneous network infrastructures. This means that we will see greater adoption of SDN across the board, including the enterprise as more businesses move away from the conservative SDN approaches of the past and look towards personalised SDN methods that cater for their markets better and more effectively.