REFERENCE
What is KVM over IP Switch?
KVM over IP devices use a dedicated microcontroller and potentially specialized video capture hardware to capture the video signals keyboard and mouse signals, compress and packetize them, and send them over an Ethernet link to a remote console application that unpacks and reconstitutes the dynamic graphical image. This KVM over IP subsystem is typically connected to a system's standby power plane so that it's available during the entire BIOS boot process. These devices allow multiple computers to be controlled remotely across a wide area network, local area network, or telephone-line using the TCP/IP protocols. Modern KVM over IP appliances or switches typically use at least 128-bit data encryption securing the KVM configuration over a WAN or LAN (leveraging SSL, and thus MD5 or AES). KVM over IP devices have been implemented in many different ways. For the graphics capture portion, PCI based KVM over IP cards use a variation of a technique known as screen scraping where the PCI bus master KVM over IP card would access graphics data directly from the graphics memory buffer. Newer techniques such as those used by OPMA management subsystem cards and other implementations obtain the video data directly from the graphics chip using the industry-standard DVI bus. There are also a variety of ways to emulate the keyboard and the mouse remotely, but newer implementations emulate USB based keyboards and mice using the management controller.