Editor's note: The confluence of terms around VMware virtual networking concepts can get confusing. Virtual networking and software-defined networking aren't the same thing, but they're often confused.
And these technologies are both still emerging. Today, a VMware infrastructure is unlikely to incorporate software-defined networking (SDN), although the technology has been much discussed since VMware snapped up Nicira in 2012.
As VMware's virtual network platforms evolve, VMware administrators will find their roles expanding beyond server and virtual machine administration, and more and more into the network layer.
We asked Sander van Vugt, author of a series on VMware-based virtual networking, to explain how virtual and software-defined networks differ.
Is "SDN" network virtualization and vice versa, or do the terms refer to different networking concepts?
Network administrators can look at software-defined networking as an enhancement of virtual networking that specifically targets Infrastructure as a Service (IaaS) environments.
SDN is network virtualization enhanced.
Virtual networking is how you create networks that go beyond a physical network device. This can relate to IT environments that use virtual machines (VMs), but virtual networks are also found in IT environments with physical machines only. An example of a virtual network is the virtual local area network, where physical switch ports are tagged as part of the same virtual network, enabling a virtual network entity that goes further than just one switch.
SDN is network virtualization enhanced. Virtual networking is still tied directly to networking hardware, whereas SDN is completely abstracted from the physical infrastructure. SDN is important in cloud IaaS environments, where customers may deploy VMs from a cloud provider tied to completely different networks. With SDN, these VMs must appear as one integrated network infrastructure. The software-defined network uses a control plane to decide where network traffic goes. The control plane communicates its instructions to the data plane, where the actual networking occurs.
This was first published in February 2013