I want to use tc qdisc settings in a network coposed of several qemu VMs, connected through bridges and tap interfaces. 

I generate traffic with a spirent. Everything is fine when the scheduling discipline is not installed but when I run the command to set taprio queues traffic on the VM's NIC the traffic is dropped, i can send max 1mbps. 

I think that there is something missing in the virtual NIC configuration or setup. With ethtool i can see that queues are configured. I've also noticed the BQL equals to 0, that is different than the physical machine (BQL=18600) where everything works correctly. 

I've read that it could be because NIC drivers do not support that setting. 

Do you have any suggestions?

Thanks you all

Silvia