This testvar must be explicitly defined in the configuration file
When TR-111 Part 2 is enabled CDRouter will automatically configure a STUN username and password on the DUT. By default CDRouter will compose a unique STUN username based on the serial number and oui returned by the DUT in the initial Inform it sends to the ACS. This testvar can be used to override this behavior and configure an arbitrary STUN username on the DUT.
This testvar was added in CDRouter 9.2