Scott Lowe was a guest on the latest episode of VMware Community Podcast and was discussing Network Virtualization. It was “a can’t” miss episode of the Community Podcast. Scott Lowe is probably one of the most technically diverse and deep cross discipline experts that I’ve read. He has deep experience with both Networking and Server Virtualization. He was a guest on the podcast to discuss Network Virtualization. I posed the question in the live chat on the difference between SDN and what VMware is defining as “Network Virtualization.” I’ll get to his response on my question in a second.
The host John Troyer brought up the argument that most networking professional bring up when discussing “Network Virtualization.” The claim is that virtualization already exists in network technologies. You have VXLAN, VLAN’s and network overlays. Scott did a great job of explaining that while these technologies virtualize transport of the network they don’t actually change the operation model of networking.
As he explained when you examine the benefits of server virtualization the main benefit outside of consolidation is the change in operations. Done right, server virtualization can allow you to completely change the way you deliver and manage your compute and storage to an extent. I like to say virtualization is like the DVR. You can record, pause and rewind your server operations since they are abstracted from the physical hardware.
Network virtualization is similar to server virtualization as it lets you abstract the operations of your network from the physical access layer. Configurations can be recorded, copied, paused and rewind. They way you provision and manage your network is completely changed by network virtualization.
How is this different from Software Defined Networking or SDN? I think VMware (who Scott works for) would like you to consider SDN as just the abstraction of the control plane from the physical plane. So in theory you could have SDN run inside of a virtual network controlling that control plan of the virtualized network. I believe the industry outside of VMware is defining SDN in a broader sense. When you think of the other Software Defined data center components such as storage its all about abstracting the management and presentation of these services from the hardware.
So, the difference between SDN and Network Virtualization depending on who you are asking. A VMware network guys would tell you SDN is about abstracting the control plane while Network Virtualization is about abstracting the entire management layer of the network including SDN. While some others would tell you that Network Virtualization is just another way of saying SDN.
He did make a statement that makes me wonder about the future of Virtualized Networks vs. SDN. My vision of SDN would be that the application is aware of the underlying SDN based network. The application can make a call to the control plane to give requirements for a connection and the SDN controller will make the appropriate pathing and connectivity decisions. Scott mentioned the similarity of applications deployed on vSphere with application deployed on a VMware Virtualized Network. The application and server would treat it just like any other network it has physical connectivity.
I’m looking forward into learning the nuance differences between the two definitions and operation.
Either way I highly encourage you to listen to the podcast. Well worth the hour.