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Seems like virtual switches are now the new "it" thing. Cisco announced one that plugs in to VMWare environments. Now comes news from Citrix Syngergy that they are also developing a virtual switch for Xen and KVM. Why all the buzz over virtual switching? There are 2 good reasons for virtual switches  - one is to make it easy to deploy and migrate virtual servers. The other is to allow network administrators access to managing virtual switches deployed by hypervisors. The former is a technical solution to help virtual machines become more flexible; the latter is a solution to an operational issue, where network administrators want control over every switch that is deployed in the data center. There is also another benefit of vswitches. It's easier to roll out new functionality in a virtual switch than it is to change a physical switch, even if it's just software in either case. Customers are less willing to upgrade their hardware/firmware on their premise networks compared to a virtual switch in a virtual environment. As a result, you may see quicker deployment of features like QoS, enhanced security, and more granular network statistics that not only monitor the physical hardware, but also the virtual networks. Be careful when looking at these virtual switches, though. A close inspection might reveal some unwanted performance side effects. For example, rather than allow two virtual machines connected on the same vswitch to communicate directly, Cisco's vswitch forces the packets to flow out of one virtual machine, to a physical switch, and then back to the destination virtual machine. That seems kind of inefficient to me. Egenera has been providing virtual switching for physical and virtual servers for many years. Because we were the first unified fabric computing system on the market, we had to face these same technology challenges on the way. Virtual switching is a natural evolution allowing server personalities to migrate to different physical hardware while at the same time preserving the network configuration and topology. The key to virtual switching is that it must fit in with the current operational environment and existing switching environment in your data center. If not, you may be getting more of a headache than a solution.