One of the many features that virtualization provides is the ability to easily change the configuration of a virtual machine. Changes to physical servers often require purchases of additional hardware, downtime of the server to install and reconfigure the hardware, and possibly running of new cables to provide networking, fiber channel, or additional capabilities to the server.
The flexibility of Hyper-V networking minimizes the amount of effort needed to make many of these changes. With Hyper-V, virtual NICs can be added or removed, network destinations can be changed, and Virtual LANs (VLANs) can be configured. These abilities allow for a more agile environment that can change as business needs change, security requirements update, or troubleshooting requires.