January 18, 2013


SDN – Not just a random good idea, but here to stay

Software Defined Networking, or SDN, may finally help us create a discipline in the networking space the same way it happened in systems domain, especially software programming with definition of abstractions, interfaces and modularity. It is interesting to understand what this change is, and why it is needed. While the service providers made architectural changes in their networks in the last few years to move to all IPs to expect a more open ecosystem of applications, the reality is that the networks have become more complex with a large abundance of protocols/control plane algorithms and a network that is very difficult to change. The real need is to have a secured network that provides mobility to the users to access the internet and its associated world of applications. The need is to leverage the advancements in computing power, routing protocols, access mechanisms and availability of the rich open source community to create a more open ecosystem that allows rapid changes and innovation to happen, while control moves to centralized software, reducing hardware costs and power while being easy to manage.

SDN is precisely defined by three abstractions – distribution, forwarding and configuration. In networking terms, SDN shall shield control mechanism from state distribution, provide a “Global Network View” or automated network graph though an API (Application Programming Interface) with a centralized control function. The control program has an abstracted view of the network (called  “Abstract Network Model”) specifying the desired behavior, which in turn is compiled to the underlying topology by a virtualization layer (“Network Virtualization”), and the “Network Operating System” transmits these settings to the physical boxes. Finally, the forwarding abstraction provides CPU abstraction for the management plane (smart but slow) and ASIC abstraction (fast but dumb) with an open interface to the underlying hardware, often achieved in the form of Open Flow specifications from ONF (Open Networking Foundation).

In simple terms, SDN provides network transition from vertically-integrated, closed, proprietary and slow innovation lead systems to horizontal, open interfaces and rapid innovation. OpenFlow is one of the standards that separate the control plane from the data plane with Open API to the black box networking node, which could be either an L2/L3 switch or a router. OpenFlow is based on an Ethernet switch (or “Open Flow Switch”) which has an internal Flow Table (for data path) and a standardized interface toward a controller which programs (control path) the Flow entry in the Flow Table.

As per the Information Week 2012 SDN Survey, July 2012, a more efficient and flexible network that speeds service delivery and cost savings on hardware are the top two market drivers for SDN adoption. North America continues to be the biggest market for SDN solutions, though APAC will experience increased market traction over the next five years to become the biggest SDN market globally. According to Gartner, SDN stands among the top critical IT trends for the next five years, and Markets to Markets predicts the global SDN market to grow from $198 million in 2012 to $2.10 billion in 2017 at a CAGR of 60.43%.

From a service provider standpoint, Infonetics Research emphasizes simplified network provisioning while from an OEM perspective, WCP Research mentions the deteriorating gross margin for hardware-based networking products in data centers as well as the need for lower cost “virtual” switching and routing functions. It is just a matter of time before OEMs implement OpenFlow via embedded functionality on merchant silicon. From an enterprise perspective, ONF trends clearly indicate SDN allowing network resources to be allocated in a more elastic fashion, enabling rapid provisioning of cloud services and more flexible hand-off to the external cloud provider.

While the industry gears up for this next revolution called SDN, there are many challenges which need to be dealt with. A few key of them include definition of mature standards covering the depth and breadth of control, data and management aspects and the mutual cooperation of leading players/vendors to evolve and eventually support higher interoperability between different platforms.

We view network programmability, open interface, virtualization and interoperability to be the key engineering imperatives of SDN for OEMs and service providers with opportunity to provide solutions that can “accelerate” product launch, add “value” to the eco-system by providing seamless management interface to the cloud and on-premise deployments and test “Technology” co-existence and interoperability. REST API enablement of platforms or Northbound API for business domain abstraction that enables integration with a higher order management system are examples where a solution accelerator can help an OEM reduce development time and cost to accelerate SDN adoption. For more on network engineering services, visit us today!.


  1. http://www.ibtimes.com/press-release/20120618/marketsandmarkets-global-software-defined-networking-sdn-market-worth-210

  2. http://www.infonetics.com/pr/2012/SDN-40G-100G-and-MPLS-Control-Plane-Survey-Highlights.asp

  3. WCP Report on Software Defined Networking – Moving Towards Mainstream (August 2012)- http://www.woodsidecap.com/wcp-electronics-banking-research-report-software-defined-networking/

  4. http://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=2&cad=rja&ved=0CDcQFjAB&url=http%3A%2F%2Fwww.necam.com%2FDocs%2F%3Fid%3D28a3203e-ef17-4f0e-b193-0edc4eb065cc&ei=jtT3UN2PGcSPrgeZ44HoCA&usg=AFQjCNGJ2-ChoY4hjo8JVRfrjBh0pVvApg&sig2=EKjxc8r9c-e07rcwKifSgw&bvm=bv.41018144,d.bmk

  5. http://onrc.net/

  6. http://www.openflow.org/wp/documents/

  7. http://cleanslate.stanford.edu/