In Microsoft® Hyper-V® Server 2008, the parent partition manages the I/O devices instead of the hypervisor.
To provide virtual machines (VMs) with access to the I/O devices, Hyper-V supports a high-speed interconnect called the VMBus. Virtual devices for each VM, such as network and storage adapters, communicate with the parent partition through the VMBus.
The parent partition receives requests through the virtual service providers (VSPs) and directs them to the underlying physical devices through its I/O stack. This model requires device drivers for the physical devices to be installed in the parent partition.
NOTE: Device-specific drivers and utilities created for Microsoft Windows Server® 2008 x64 operating system do not require any change when Hyper-V is enabled.
NOTE: It is recommended that you download the latest Dell-certified drivers available for your system and install them in the parent partition. Using the latest drivers ensures that both the parent partition and the VMs are able to utilize the underlying physical devices. Download the latest device drivers from the Dell Support website at support.dell.com.
Guest operating systems require specialized drivers (VSCs) provided by Microsoft to access the VMBus. The drivers are specific to the type of device that is presented to the guest operating system through the VM configuration. They are installed as a part of the Integration Services available for the Hyper-V supported guest operating systems.
NOTE: All architecture-related information provided in this document assumes that the guest operating system has Integration Services installed.
Virtual Network Adapters
VMs can be presented with two types of virtual network adapters: Legacy (or emulated) and Synthetic.
Legacy devices emulate a physical network adapter in software. Although this process provides networking services to a VM, it requires additional host processing resources.
Synthetic devices are comparable to proxy devices that present themselves as network devices, but only pass bundles of data along the VMBus to other networking resources. This process does not require software emulation, and therefore offers higher networking performance for VMs. It also lowers host system overhead.
Virtual Switches
A virtual switch forms the heart of connectivity in a Hyper-V virtual network. The virtual switch functions like a physical network switch by connecting physical and virtual network adapters. Like a physical network switch, a virtual switch has internal and external switch ports (network ports). The configuration of these ports is based on the type of virtual network created.
The following sections introduce virtual network types, discuss how they differ, and provide best practices for implementing each switch.
