In network virtualization, what does a single physical infrastructure provide?

In network virtualization, a single physical infrastructure can support multiple separate networks. This capability is fundamental because it allows organizations to create distinct virtual networks that can operate independently on the same physical hardware. By utilizing virtualization technology, such as VLANs (Virtual Local Area Networks) or VPNs (Virtual Private Networks), various network segments can be deployed over the shared physical infrastructure while maintaining separation in terms of security, traffic, and administration.

This separation is critical for environments where different departments or applications require distinct policies or performance metrics. Additionally, this approach enhances resource utilization by reducing the need for additional physical hardware, thereby optimizing costs and management processes.

The other options do not accurately capture the essence of network virtualization. While a single network for all devices might imply a simpler configuration, it contradicts the purpose of virtualization, which aims to create separate and independent networks. Increased data traffic is a potential consequence of poor design or management but is not a benefit or fundamental feature of virtualization itself. Lastly, physical isolation for all devices does not align with virtualization principles, which inherently involve sharing physical resources while ensuring logical separation.