Single-root input/output virtualization

In network virtualization, a single root input/output virtualization or SR-IOV is a network interface that allows the isolation of the PCI Express resources for managability and performance reasons. A single physical PCI Express can be shared on a virtual environment using the SR-IOV specification. The SR-IOV offers different virtual functions (VF) to different virtual components (e.g. network adapter) on a physical server machine.
The SR-IOV allows different virtual machines in a virtual environement to share a single PCI Express hardware interface. In contrast, MR-IOV allows I/O PCI Express recources sharing among different VMs on different physical machines.