Microsoft's RNDIS vs. Belcarra's USBLAN for Windows - Deployment Costs

RNDIS is Microsoft's solution for providing a networking over USB solution using their proprietary RNDIS protocol.
USBLAN for Windows is Belcarra’s solution for providing a networking over USB solutions using the industry standard protocols CDC-ECM, CDC-EEM and CDC-NCM.
While there are no licensing costs associated with the use of Microsoft’s RNDIS driver this does not mean that the actual cost of deploying a commercial product will be less when RNDIS is implemented.

The Total Cost of Deployment for a USB device using a network over USB solution is composed of multiple items:
  • cost development of the device side protocol support 
  • cost development and testing of the Windows Installation kit 
  • cost of setting up Windows Logo Kit test setup 
  • cost of doing Windows Logo Kit testing 
  • opportunity costs associated with delays while developing the installation kit 
Device Side Implementation Costs
Also support for RNDIS is limited to Windows based systems on the host side. This means that the device must still support another standard (such as CDC-ECM) for compatibility to Linux or Macintosh hosts.

Windows Logo Kit Testing Setup
Windows Logo Kit testing requires:
  • Server 2008 system to run DTM Studio 
  • two 64bit systems to run Vista 64 and Windows 7 64 to run DTM Client 
  • three 32bit systems to run Windows XP, Vista 32 and Windows 7 32 to run DTM Client 
 The DTM Client systems need to be maintained with all current patches from Windows Update and saved. The testing process requires installation of the “test driver kit” so these systems must have an image backup so that they can be restored to their original (plus updates) condition prior to each new set of testing.

Windows Installation Kit
A proper Windows Installation Kit ensures that the customer experience for your device matches expectations. More specifically a seamless and silent installation that results in trouble free use of your device without support issues.

To accomplish this a proper installation kit is required following Microsoft's standards and rules. This must be tested using the Microsoft Windows Logo Kit to ensure compatibility and then distributed using a Microsoft signed kit. This kit can be made available via Microsoft's Windows Update Driver service or distributed as an easily installable package for end users without a network connection.

While RNDIS is available from Microsoft, it must still be built into a distribution kit. So the following engineering tasks must be budgeted for:
  • development and testing of the installation INF 
  • testing with your Developer Code signing certificate 
  • running the WLK tests against your kit for all the test client systems 
Belcarra’s USBLAN for Windows is provided as a complete ready to use kit that can be deployed using your VID/PID from Microsoft's Windows Update Driver service and as a ready to distribute kit for your end-users. This eliminates both the engineering costs associated with this process and reduces the time to implementation to zero.