Address Management and Device Discovery


This paper describes how to build and manage a TCP/IP network for USB devices.
Ethernet-style networking  can very simply be  extended to attached USB devices. Belcarra’s USBLAN for Window’s built-in DHCP server for address assignment, management and device discovery solutions has been implemented to fit within the network paradigm requirements. USBLAN for Window’s implements USB-IF ( Communications Device Class protocols (CDC-NCM, EEM, ECM and others) and will create an Ethernet-style networking segment for each attached USB device.
Networking over USB protocols such as CDC-ECM, Microsoft RNDIS, CDC-NCM, were originally designed to provide USB-mediated access to an external network, and address management was seen as a matter for the external network segment.  On such external segments, a DHCP server was usually available.
Now, however, the great majority of USB devices using these protocols are smart devices which use a network style command channel, but do not provide access to an external network medium.  Therefore, the network segment terminates at the device, and there are only two nodes on the network: the USB host (Windows) and the device.  The DHCP service within Belcarra USBLAN for Window’s is a special service for such network segments.
The following describes how the network layer (IP) addresses can be seamlessly set up on top of the link layer and some pointers and strategies on OEM software running on Windows co-operating with the device to enable network-based device discovery.