Ubuntu 16 / Fedora 26 / CentOS 7 cdc_ncm no bridging support?
 

I have a configuration where I present a network connection with two tagged VLANs to my laptop. This permits network isolation of VM's I run on this laptop. I'm using kvm-qemu and I simply bridge the network connections via qemu's native methods. The bridging ensures the VM's do not route (or NAT) through the laptop's TCP/IP stack and participate directly on the business networks.

The onboard ethernet (e1000e/eth0) of the laptop supports tagging and bridging, but the onboard is also a standard RJ-45 port and not a dock port.

The ethernet port (cdc_ncm/usb0) on the VisionTek model 901005 registers as using the cdc_ncm driver, which doesn't appear to support bridging. This is an issue since virtual machines I run on this same laptop need to participate in the VLAN I have assigned through kvm-qemu.

I have tried Ubuntu, Fedora, and now I'm on CentOS. The problem persists across all three distros.

I'm not in need of any additional workarounds, as I have that already using the e1000e; rather insight in to how to fix the actual problem.