This is an optimization technique for a guest operating system to make it aware of virtual machine environments and to shape its behavior when it is running in a virtual environment. There are some important and great benefits with the IC. The VSC (Virtual Service Client) is a synthetic device that resides in a child partition. When you install the IC you also install the VSC that makes the VM able to communicate over the VMBus – with the VSP (Virtual Service Provider).
The VSP provides the needed support for those synthetic devices in the parent partition requested by the VSC, in the child partitions. In other words: the VSP is how the VMs gains access to the physical devices on the parent.
IC does not require changes to the OS, and help to reduce the overhead of certain operating system functions such as disk access and memory management.
The Integration Components supports the following services:
1) (IDE, NIC, SCSI, mouse, video) Synthetic devices
2) Time Synchronization
3) Data Exchange
4) Volume Shadow Copy Service
5) OS Shutdown
What if the IC is not installed?
VMs without IC installed (so called ‘legacy guests’) do not have the access to the VMBus or VSCs. In other words, there is no support for synthetic devices. This affects performance, and will result in a software emulation of hardware device drivers in the operating system to the parent partition. Back to performance: VMs without IC installed, would perform at a much lower level than the VMs with IC installed. Software emulation of hardware devices may require thousands of instructions, compared to a few instructions directly in the hardware.
In addition: the IC is included in the distribution of Windows Server 2008 R2 and Windows 7, so there is no need to install the IC separately after the deployment in Hyper-V.