Date Added: May 2012
Recent development on Ethernet switching to provide Single Root I/O Virtualization (SR-IOV) on Network Interface cards (NICs) improves Ethernet throughput for Virtual Machines (VMs) and lowers CPU loads. SR-IOV creates multiple receive queues on a NIC, directly accessible by VMs for frames coming from sources external to the Ethernet port. This virtualization of Ethernet ports and the presentation of frames directly to VMs eliminate a major cause for CPU loading by reducing the interrupts for receipt of inbound frames. However, SR-IOV cannot provide switching support for two VMs on the same computer; the only existing switching option is software-based switching in the hypervisor, which limits throughput and results in high CPU utilization.