There is no question that SDN is the hot new technology that has suddenly made networking interesting and fun all over again.  With market forecasts estimated in tens of billions, spectacular valuations have been applied to early stage start-ups and every networking vendor worth its salt seems to be coming up with SDN solutions.  It's raining SDN in the networking industry!

So is SDN for real?  And if so, what is it?

Recently I participated in an industry panel discussion on SDN. One of the questions the panel was asked was exactly this: Is SDN for real?  Here is my perspective on SDN.

To us SDN is about bridging the gap between applications and networks to enable the rapid consumption of network services by providing visibility and control to the applications.  It is about providing abstraction of network capabilities and it is about automation of  network provisioning.  It is about separating what applications need from how the network implements it.

This requirement for rapid consumption of network is most pronounced in the emerging cloud services market driven by the broad-based shift of IT to the cloud.  The CIOs, IT admins and Cloud Service Providers are increasingly facing the challenge of meeting the requirements of rapid deployment of applications wherein the network must quickly adapt to the service requests of applications.  The ultimate goal of an SDN solution is to simplify operations, increase agility and accelerate deployment of new services. It is for these reasons that SDN is receiving widespread attention from Enterprises and Service Providers that are currently operating networks with burdensome provisioning models and operational complexity.  SDN promises to change it all.

The ideal SDN solution must abstract, virtualize and automate any existing datacenter network. That ensures preservation of investments while drastically reducing the delay, cost and complexity inherent in today's paradigm.

Abstraction of network resources and capabilities drives programmability. Any arbitrary service design for a tenant should be designed by the IT administrator or cloud service provider using simple high-level constructs.  Examples of such service designs are the three-tier web services, disaster recovery services or hybrid-cloud services with VPN connectivity to the Enterprise.  Effective implementation of role-based hierarchy within the cloud datacenter SDN solution ensures that the top-level admin retains full control and visibility,  yet allows granting of full permissions to a 'sand-box' of service templates and design for users in lower levels of the hierarchy.

In addition, an optimal SDN solution instantly and automatically establishes network connectivity between virtual machines as soon as they are created on a per-tenant basis.  It should elegantly support L2-L4 networking services by deploying overlay technologies, to not only address the scaling issues of Layer 2 VLANs, but also optimize Layer 3 traffic paths regardless of virtual machine (VM) location. It provides seamless connectivity to Enterprise VPNs.  Furthermore, Layer 4 functions are distributed to reduce the need for centralized firewall appliances that secure VM traffic.

This drastically improves server utilization by allowing VMs to be freely placed or relocated wherever compute resources are available, within and across datacenters. By optimizing traffic across the datacenter fabric, SDN provides new levels of cloud application performance and DC fabric efficiency.