Driver Overview

Belcarra USBLAN for Windows is a USB Class driver used to create and manage a USB networking link between a Windows host and an OEM device using industry-standard USB networking protocols.

When a matching device is connected, USBLAN loads for the network function and creates a virtual network interface that operates like an Ethernet interface over the USB link.

Current primary target

Windows 11 amd64
Windows 11 arm64
Windows 10 amd64 (Note: ARM64 is supported on Windows 11 only)

Protocol coverage

CDC-NCM
CDC-EEM
CDC-ECM
RNDIS

Host Driver Architecture

The diagram below illustrates the relationship between Windows networking applications, the NDIS boundary, the Belcarra USBLAN kernel-mode driver (usblan.sys), the Windows USB bus driver stack, and the physical USB host controller:

Belcarra USBLAN for Windows Architecture Diagram — Figure 1: Windows Host Architecture — Belcarra USBLAN (usblan.sys) NDIS miniport, composite parent (USBCCGP), and USB bus driver interaction.

Operational model

For each connected device instance, USBLAN creates a Layer 2 network interface over USB transfer frames.
Turnkey nested installation kits make USBLAN simple to use for OEMs and for their end customers, supporting branded pre-installation and silent deployment.
Plug-and-play installation from a local driver store or Windows Update (based on kit configuration).
Optional built-in DHCP service to coordinate host/device IPv4 addressing on point-to-point USB segments.
Supports composite devices by matching the interface (MI) for the network sub-function.

Engineering features

IPv4 and IPv6 support
Power management support (sleep, standby, hibernation, resume)
Microsoft hardware certification workflow compatibility
Multiple simultaneous USB devices (up to sixteen per host)