[AVB] Linking of Virtual Alsa Device with Actual Sound card

Hello,

To enable AVB streaming, I do have utility(streamhandler) supplied from 
supplier.
With utility I can connect virtual ALSA device to feed Audio for outgo 
stream(Transmitting stream).

My doubt is regarding "virtual ALSA device". Virtual ALSA device created 
do not have any audio data even though while creating it I pass working 
ALSA plugin( which is verified with Aply and Arecord) as a parameter.

As per theory, virtual ALSA device (referred as numbers 0,1,2,... n) are 
links to Actual ALSA devices of system.

Do any on of you have an idea about Virtual ALSA Stream?