6.0.1

Connecting a USB passthrough device to a virtual machine that runs on the ESXi host to which the device is
physically attached requires an arbitrator, a controller, and a physical USB device or device hub.
USB Arbitrator
Manages connection requests and routes USB device traffic. The arbitrator is
installed and enabled by default on ESXi hosts. It scans the host for USB
devices and manages device connection among virtual machines that reside
on the host. It routes device traffic to the correct virtual machine instance for
delivery to the guest operating system. The arbitrator monitors the USB
device and prevents other virtual machines from using it until you release it
from the virtual machine it is connected to.
USB Controller
The USB hardware chip that provides USB function to the USB ports that it
manages. The virtual USB Controller is the software virtualization of the USB
host controller function in the virtual machine.
USB controller hardware and modules that support USB 3.0, 2.0, and USB 1.1
devices must exist on the host. Eight virtual USB controllers are available to
each virtual machine. A controller must be present before you can add USB
devices to the virtual computer.
The USB arbitrator can monitor a maximum of 15 USB controllers. Devices
connected to controllers numbered 16 or greater are not available to the
virtual machine.
USB Devices
You can add up to 20 USB devices to a virtual machine. This is the maximum
number of devices supported for simultaneous connection to one virtual
machine. The maximum number of USB devices supported on a single ESXi
host for simultaneous connection to one or more virtual machines is also 20.
For a list of supported USB devices, see the VMware knowledge base article
at http://kb.vmware.com/kb/1021345. You can add USB 3.0 devices to Mac
OSX guest operating system for VMware Fusion.
USB Autoconnect Feature
When you add a USB device connection from an ESXi host to a virtual machine, the autoconnect feature is
enabled for the device connection. It is not disabled until you remove the device connection from the virtual
machine.
With autoconnect enabled, the device connection re-establishes in the following cases:
n
The virtual machine is cycling through power operations, such as Power Off/Power On, Reset,
Pause/Resume.
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The device is unplugged from the host then plugged back in to the same USB port.
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The device is power cycled but has not changed its physical connection path.
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The device is mutating identity during usage.
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A new virtual USB device is added
The USB passthrough autoconnect feature identifies the device by using the USB path of the device on the
host. It uses the physical topology and port location, rather than the device identity. This feature can seem
confusing if you expect the autoconnect feature to match the connection target by device ID.
If the same device is plugged back in to the host through a different USB port, it cannot re-establish
connection with the virtual machine. If you unplug the device from the host and plug in a different device to
the same USB path, the new device appears and is connected to the virtual machine by the autoconnect
feature that the previous device connection enabled.
vSphere Virtual Machine Administration
140 VMware, Inc.