Software Defined Networking is a meaty topic and a good follow-up to last week’s conversation on Software Defined Storage. There's a lot at stake from both the software and hardware vendors in this space. Both VMware, who’s trying to get their foot in the door and Cisco, who’s trying to maintain market dominance have skin in the game. All SDN vendors have to answer the same question, do we really need this whole idea of a policy based programmable network?

There’s a great deal of fear, uncertainty and doubt (FUD) so, I figured I'd tackle this from a business perspective. From the perspective of the why we do IT and then back our way into the technology constructs verses others.

Let's talk about the business challenges software-defined networking or the programmable network solves. Not the technology challenge but the business challenge. This is how we actually sell all these technologies into our enterprise, whether we're a network administrator trying to convince our network manager or director or CIO to accept these technologies. Or a CIO trying to sell to our CEO the whole concept of a programmable network and the value it gives the business.

The business problem

It’s about trying to overcome the drivers that force businesses to look at shadow IT spawned by the likes of Amazon and Google. When business owners get frustrated with IT and its ability to execute upon strategy, they go where their needs can be quickly served. If a business owner has to wait 3 to 6 months as a network is designed and built to accommodate a new application that provides a competitive advantage there is a problem. Software defined networking aims to solve this specific problem in the enterprise.

Networking lags compute & storage

Cloud computing is about the ability to provide an enterprise customer with the agility and capability needed to host applications and services on demand. Provisioning networking is the bottleneck of the 3 major service areas. When you think of the time it takes to provision x86 compute or storage, there is no comparison. We like to beat up the storage groups and vendors about the complexity of storage, but the truth is once storage is provisioned the virtualization engineer doesn’t need to talk to the storage engineer until more storage is needed.

Networking is very unique in that every time you setup a new application, new firewall rules are needed, VLAN’s have to be setup and let’s not forget load balancing for high availability. If I have to extend my application out to the cloud or connect with a business parnter, I have to figure out how to do this securely. The network becomes a bottleneck in the cloud workflow. When you look at the three building blocks (Cinder, Nova, Neutron) of the OpenStack, for example, the question comes to mind of where’s the meat behind orchestration and problem solving of managing the mess of the existing network.

The Solution

Projects such as Open Day Light and Opencontrail and solution such as NSX and Cisco’s ACI aim at solving these challenges. VMware’s theme of from VMware 2013 for NSX was faster was the driver for SDN. The faster you can provision, the more integrated into your operations and, consequently, the more value delivered by the network. The argument for NSX and ACI is the agility that both solutions bring. I’ve often made the argument that Cloud Computing is more about agility than cost savings. The software defined data center is the same argument.

If we can make the argument to the business that not only can IT be just as responsive as AWS but add more capability, we can fight shadow IT. The ability to integrate into existing enterprise systems such as in-house collaboration tools, CRM and ERP are true enablers. It’s this argument that will allow us to fight shadow IT. It’s on this basis that software defined networking brings significant value.

The options

There are two flavors of SDN from the major vendors (Cisco & VMware). VMware’s approach is to virtualize everything. They are a virtualization software company and, therefore, their argument is around the advantages of virtualization. Putting a software wrapper (NSX) around the abstracted network allows the application layer to orchestrate and consume the network. Cisco has a slightly different approach. Cisco provides an API to a hardware controller that aims to give the same functionality as a virtualized network without sacrificing performance.

There are pros and cons to each method. VMware allows for a hardware agnostic approach. If the physical network (the underlay) is multi-vendor, then NSX can still take advantage. Cisco, on the other hand, allows for a completely hypervisor agnostic solution. VMware’s NSX doesn’t support Hyper-V and since Cisco is a hardware play the underlying OS doesn’t matter. Cisco also has the advantage of the major relationship with network providers which may translate into extending SDN services from your network provider.

In closing

Back to the main point and why we care about software defined networking. The point is to enable the business with the full promise of cloud computing. When we give the application the ability to control the network, we enable the business the capability to move as fast as their ideas.