A method of providing high density expansion of a USB network, the method comprising: attaching a plurality of USB hubs to adjacent slots in a PXI instrumentation chassis; configuring one of the USB hubs as a primary USB Hub; connecting an upstream port of the primary USB Hub to a USB network; configuring a first downstream port of the primary USB Hub to communicate across a first PXI Local Bus to a first adjacent USB Hub of the USB Hubs other than the primary USB Hub, the first adjacent USB Hub being adjacent to the primary USB Hub; configuring a plurality of other downstream ports of the primary USB Hub to provide expansion of the primary USB Hub; connecting an upstream port of the first adjacent USB Hub to the first PXI Local Bus, wherein the first PXI Local Bus is in the direction of the primary USB Hub; configuring a first downstream port of the first adjacent USB Hub to communicate across a second PXI Local Bus to a second adjacent USB Hub of the USB Hubs other than the primary USB Hub, the second adjacent USB Hub being adjacent to the first adjacent USB Hub; configuring a plurality of other downstream ports of the first adjacent USB Hub to provide expansion of the first adjacent USB Hub; and configuring any other of the USB hubs and the first adjacent USB Hub in like manner.