A different take on Software Defined Networks

Jan 29, 2013

By Mark Pearce, strategic alliance director at Enterasys Networks

Software Defined Networks (SDN) are here to stay, but in a different form from what many people might be thinking.

Until recently, the industry has been focused on just the technical details, and not on the value that SDN can bring to the table. The notion that SDN is just for datacentres or service providers is simply not true. SDN provides a lot of value to the enterprise – from their datacentres down to the mobile and wireless edge.

The early days of SDN focused on implementation details like the OpenFlow protocol (for the Southbound API) and created a myth there are capital savings (CapEx) associated with the technology. However, my experience with SDNs has shown that the operational cost savings (OpEx) that can be realised are considerably more significant.

Not only does SDN allow administrators to create new services, but it also makes the administration of the overall network considerably more efficient. CapEx savings have been realised via the use of less expensive switching equipment, but network scaling quickly makes these savings illusionary. The underlying requirements of the data plane in SDN are scaling at a rapid rate in terms of flows (a key element of a SDN architecture) – much higher than any of today’s commodity ASICs can handle. Only custom flow-based ASIC designs can address those requirements.

The main benefits of SDNs are clearly the OpEx savings, which customers are already experiencing today. SDN is all about making the network more programmable to address business benefits such as:

Improved network efficiency through centralised management and better service control across the whole network fabric for any device, user and application so that a high and consistent user experience can be achieved, with compelling OpEx savings

• Improved IT agility through fast and reliable application services from the virtualised datacentre to the mobile edge

• Providing advanced analytics of all resources so the organisation can easily monitor and control these resources and make strategic business decisions

SDN is really about a programmatic interface into the network fabric that allows network administrators, other IT teams and applications to provision new services on the go.

SDN services include:

• Network virtualisation beyond only vSwitch integration

• New service provisioning – in an orchestrated or overlay approach

• Traffic engineering – where this might be the only use case where a southbound API like OpenFlow would make sense

Other services such as load balancing will follow as vendors continue to develop new and innovate SDN applications that meet the emerging requirements of its customers. The benefits of SDNs are operational/functional and are tied to these new services. A higher degree of agility, new services, lower operational cost and a simplified network operation and design is the result.

Networking vendors are providing solutions today, which serve as examples of new service provisioning in a SDN context. The solutions work to do the following:

• Orchestrate physical and virtual networks in an automated fashion

• Automatically provision services and policies as well as real-time tracking of connected devices and users

• Mobile Device Management systems for automated service provisioning for managed mobile devices and bring-your-own-device (BYOD)

SDNs should address practical needs to create a dynamic and agile network infrastructure aimed at the deployment of new services through common APIs. Increased network reliability, simplicity and security are the result of a solid SDN architecture. This results in a consistent user experience coupled with compelling OpEx savings.

Last but not least, device, user, service and application visibility coupled with advanced analytics allow organisations to make faster and more strategic business decisions in order to stay relevant.

Expect more to follow from vendors on SDN and their individual architecture offerings, which will be set to scale much more efficiently than the centralised approaches that are being deployed today.




Image: Shutterstock

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