For some reason, I had a difficult time with the basic concept of Network Virtualization. VMware equates network virtualization to Server Virtualization. With server virtualization you can deploy an application to any physical server in your environment easily because the Server OS that the application resides on is abstracted from the network. This gives you an incredible amount of flexibility operationally. You can easily manage OS images, clone virtual machines, create entire test environments with almost a push of a button. It streamlines server deployments because you can now deploy servers based on templates with almost no regard to the underlying hardware.
I’ve done server virtualization long enough that I just get it. It seems natural to this point. What doesn’t seem as natural is Network Virtualization. I re-read the VMware post announcing the NSX product and it all kind of just clicked for me. I had a problem disassociating the physical access layer with the abstracted network component. After all it makes sense that the device that the port is connected to is the device that controls the behavior of the device of the network.
The Physical Infrastructure really is just that that the physical infrastructure. It’s the assurance that every device is physically connected to the network. It can be via Token Ring, Frame Relay, Ethernet or ATM. In theory it can even be a overlay network. It really doesn’t matter from a logical perspective. You have to ensure that the physical infrastructure is reliable and meets the latency requirements of your applications but that’s it (maybe a bit oversimplified). Now that there is physical connectivity a solution like NSX can take over. You create virtual ports and associate them to physical ports or other virtual ports on virtual switches. These virtual ports can then be assigned to a virtualized Firewall, Switch, Router or IDS ports based on the need.
Cisco has a similar device level approach with their ISR architecture. A port on an ISR router can be an IDS, Firewall or Router port as examples. Network virtualization just takes the abstraction one level higher and broadens the capability of each individual port. You now eliminate physical limitations of the device and virtualization the capability of the port.
The virtualized network devices can then have all the characteristics we associate with server virtualization. They can be cloned, copied, vMotioned, DRS’d and snapshot. Many of the operational advantages associated with server virtualization is now available to us on the network. The only requirement again is that there is physical connectivity and VMware is able to do the easy part which is create a network Hypervisor capable of creating the robust abstraction layer needed to manage all of these dynamic ports. I can see a pretty significant challenge in creating a high speed/low latency fabric. I can also see where troubleshooting physical vs. logical performance will be a challenge. However, these were some of the same challenges server virtualization faced during the early years as well.
I haven’t been excited by networking since I got a sample loaner Gigabit switch back in 2001 from Cisco. This is actually a pretty big deal and I look forward to seeing a shipping product from VMware and customer feedback. Your thoughts, is this a operation model that translates to your network?