Many server admins have been exposed to virtual networking concepts. Virtual NICs, virtual switches, and the like are common-place in today’s Hyper-V environment. Some application workloads operate just fine in this virtual world. But in more complex scenarios, such as those I described in the post “Using an Application-Centric Approach to Make the Most of Software-Defined Networking,” more is required to orchestrate both physical and virtual networking components—especially for applications with heavy north- and southbound traffic requirements. In these scenarios, the use of software-defined networking (SDN) technology provides a software abstraction for managing both physical and network devices and the communication between those devices and the applications.
Is your goal to create a utility-based computing infrastructure that seamlessly responds to capacity demands, lets workloads migrate to the most appropriate infrastructure (public or private), and maintains customer service levels along the way? Then network automation is important, and a software-driven network that can communicate to physical network devices from potentially different vendors is crucial. This is the promise of SDN.
That’s not to say that virtualized networking is insufficient for some application workloads. An application that lives strictly within the virtual datacenter and communicates simply to outside users might not need this level of automation and abstraction. But increasingly, IT shops are finding that applications such as Microsoft SharePoint or Lync have unique needs and unique network flows that require a software-driven approach in all but the simplest networks.
In addition, if you virtualize your physical networking components but still manage them the way you manage physical networks, your capabilities will quickly be outstripped by the complexity and demands of a cloud-enabled datacenter. For the network to respond dynamically to the needs of your applications, rather than the applications needing to react (and potentially fail) based on network limitations, the network should be fully automated, policy-driven, and integrated from physical to virtual and from private to public clouds.
If you are looking to create that kind of dynamic, utility-based datacenter, then SDN-enabled technologies can help. Virtualization platforms such as Windows Server 2012 R2 Hyper-V and the management tools within that platform can facilitate your goal. At the end of the day, you want your network to work for you, not the other way around. That is the promise of SDN. To learn more about it, visit http://www.microsoft.com/en-us/server-cloud/solutions/software-defined-networking.aspx.