The latter three are part of the larger Communications Device Class (CDC) group of protocols of the USB Implementers Forum (USB-IF).
However, minor modifications of the standard subsets make practical implementations possible on such platforms.
These new devices are still much lower in power than desktop PCs, thus the issue of careful data handling arises, to maximize use of DMA resources on the device and minimize (or eliminate) copying of data (zero-copy).
The USB-eth module in Linux makes the computer running it a variation of an Ethernet device that uses USB as the physical medium.
[1][2] On Linux hosts, the corresponding Ethernet-over-USB kernel module is called usbnet.
The approach allows devices with very limited communications hardware to operate over IP networks.