Q-in-Q tunnelling, or dot1q tunnelling, is a technology used by service providers. Its purpose is to keep customer traffic separate at layer-2.

This does not work in older versions of VIRL (tested in v1.2.83). The IOSvL2 images does allow Q-in-Q configuration. Packet captures show ARP frames with stacked VLANs. The problem is that the frames get dropped.

Several VIRL users have lamented the lack of Q-in-Q support.

Newer versions of VIRL now support Q-in-Q (tested in v1.5.145, IOSvL2 v15.2).

The VIRL feature list page for the IOSvL2 also does not list Q-in-Q support. This is a bit old now, and appears to be out of date.