I am here to argue that if you are already using a major cloud provider, you are in effect using software defined networking and services. I will refer to the Software Defined Data Center as SDx rather than just SDN. I also blur some terminology here. But the effect should be to make you feel a bit like you are already exposed to SDN in some constructive ways.
In one view of the ideal IT world, you consume IT services to enable your organization or to enhance offerings for your customers. You use it freely and it does exactly what you need. In that world, as long as it hits your SLA, cost, operations, performance and compliance requirements, do you care who offers it?
Public cloud offerings offer load balancers, VPN services, firewalls, storage, compute, application extensions and whole swaths of other features. Most of these features involve APIs that you can leverage. If you compare these features against SDx, how is it really different?
Materially, with SDx we are not talking any different services. We are talking about where you spend your money, where you house equipment, what services it provides, the APIs to go with it and, ultimately, how well you leverage it. Leveraging SDx will take time while there are cloud-like versions or abilities out now.
For example, odds are that you most likely have at least one of the following: physical firewalls running with virtual contexts, VMware clusters running virtual firewall VMs and/or virtual firewalls running within a public cloud. All of these three provide firewall services. But how you consume them can be made nearly identical. How are you making changes to them?
If you are using automation to make changes, you can look at these three kinds of firewalls nearly as identical services. Firewall services can be changed or scaled with the use of APIs. Swap out the firewall metaphor with a load balancer and you add yet another layer of automation services. With proper programming and policies, long term you could almost make yourself vendor neutral.
There are operational concerns I do not mean to gloss over. However, as long as you’re talking APIs, the nature of the service almost becomes irrelevant. Long term it will be about managing policies regardless of the hardware or software.
Whether your environment is SDx-based or cloud, the ballpark idea behind how you control your IT can very much be the same from a logical perspective. As time moves on, major vendors will evolve and hopefully provide a clearer way to get SDx without lots of equipment or software uplift. They are, after all, already competing with a cloud version.