Traffic Shaping

Hello
I want to simulate WAN speeds in a test environment.

Therefor I want to limit the bandwidth in/out from a certain host to x and in/out from another host to y.

These hosts establish IPSec tunnels with the m0n0wall.

I need to know if the traffic shaping happens before or after the IPSec processing.

After would be good (so that it is almost the last thing happening before transmission)

Thanks for your help