SDN: the long-term view

Companies re-examining traditional network architectures turn to software-defined networking for answers.

Read time 4min 20sec

It's no secret that the proliferation of mobile devices on corporate networks, fuelled by the bring your own device (BYOD) phenomenon, has placed increasing strain on existing network infrastructures. They're seldom geared to provision services and applications in the face of increasing network usage linked to enterprise-wide BYOD adoption.

What's more, supposedly time-proven access policies are no longer able to ensure network security - or reliability. And the user experience is currently at risk due to overload in many corporations with a BYOD policy; said to be 76% of all global enterprises, according to research.

Nevertheless, smart mobile devices - phones, tablets and laptops - have the potential to be game-changers for the organisations geared to accommodate them. This means providing new end-to-end services and applications in a seamless and cost-effective manner.

To achieve this goal, many companies are re-examining traditional network architectures while turning to software-defined networking (SDN) for answers.

Why SDN? Traditionally, networks have been built to connect end-users using hierarchical switches, routers and other devices in a distributed fashion. This design made sense in the days when client-server computing prevailed. Today, however, these static architectures are not suited to the dynamic computing and storage needs of modern networks supported by virtualised data centres, campuses and carrier environments.

Engineered for evolution

With SDN, the legacy static network can be engineered to evolve into an extensible service delivery platform capable of responding quickly to changing business and end-user needs - and marketplace requirements.

SDN is, in essence, a platform capable of automatically provisioning (and applying policy to) new services and applications on the fly. It achieves this by using a programmatic interface to deploy the services and applications which treat the entire network fabric as a single entity. The result is a more agile, flexible and easily orchestrated network, requiring less time to manage, thus reducing operational costs.

Many market analysts agree that SDN is applicable to almost any complex network challenge, including the automation of virtualised data centres and the automatic provisioning and management of virtual machines within them.

SDN is applicable to almost any complex network challenge.

However, SDN is not - as some protagonists have suggested - the answer to rising capital expenditure in the long term, because it can be linked to cheaper 'commodity hardware' purchases right now.

In reality, commodity hardware, because of its inability to handle many millions of data flows, simply won't scale to provide the granular intelligence needed for true software automation.

Therefore the only long-term answer to successful SDN implementation - as traffic increases and networks become more and more complicated - is purpose-built hardware capable of servicing and controlling these massive data flows.

Today's commodity hardware, if deployed, will only serve to create scaling issues that SDN will be unable to resolve down the line.

The associated promise of vendor independence through SDN is also patchy. In future, organisations that invest in SDN controllers will still be dependent on their vendors; the dependence will simply move from the infrastructure to the controller layer of the network.

Opportunity knocks

Looking ahead, SDN's most substantial benefits will come from making networks more programmable by operators, enterprises, independent software vendors and users using common programming environments. This will give all parties new opportunities to focus on profit and marketplace differentiation.

This will be achieved by new levels of service innovation and agility, scalability and operational simplicity. It will also be realised by end-to-end centralised management and control across the entire network fabric, from the data centre to the access layer for any device, user and application.

Additionally, with SDN, the control of the network data plane can be managed at a more granular level, providing the tools for abstracting the underlying network infrastructure from end-user applications.

As a result, enterprises will be able to gain unprecedented levels of automation and network control, enabling them to build highly scalable and flexible networks that will readily adapt to the changing business needs of the future.

SDN-savvy organisations are already headed in this direction. Virtualisation in the data centre, a commonly discussed application of SDN, is enabling a level of flexibility and resource efficiency that is proving hard for IT managers to ignore. Moreover, SDN is also helping to facilitate the cloud computing solutions that promise to orchestrate resources within and outside the data centre with those in the network.

The time will soon come when, with the help of an SDN-enabled network architecture, an end-user in a BYOD-enabled environment will be able to pull up a mobile app and instantly trigger the creation of a virtual machine and its associated network and storage resources - without the user or corporate IT team being aware of it.

Martin May

Regional director (Africa) of Extreme Networks.

Martin May is the regional director (Africa) of Extreme Networks. The author of the book: “Everything you need to know about networking”, he is a leading authority on infrastructure security using NAC, IDS/IPS and other network-based technologies. With experience gained in Russia, Germany, UK, the US and various parts of Africa, he is directly involved with system design and implementation at enterprise level. His emphasis is on the evolution in network architectures brought about by the concept of cloud computing. May hosts regular workshops assisting South African dealers and resellers to understand the implications, complications, opportunities and international trends surrounding the cloud. A proponent of social networking for business, he is active on Facebook and makes extensive use of YouTube.

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