[CentOS] tc seems to have no effect on the NIC's

Hello all,

We have installed this network testing environment:

https://github.com/facebook/augmented-traffic-control

which seems pretty nice overall.

It allows you to artificially degrade your network performance by issuing tc commands to directly affect your networking.

I have it set up on two CentOS 6 machines - one a Dell server, one a VirtualBox VM. The tc syntax seems OK, it seems to all make sense - only it seems to have no effect whatsoever on the actual network performance.

Hence the question: is there a known issue with tc? Am I perhaps missing some kernel modules, or do I perhaps now have some kernel parameters set correctly?

Any insight will be helpful.

Thanks in advance,

Cheers,

Boris.