I am doing this on a network with 600 routers. I have a LEDE box with 3 gigabit interfaces, 2 bridged (unmanaged) and 1 management. The box is transparent to the network and it is sitting in between my customers and the main NAT router. I modified the cake code to use up to 65535 flows. It's running on a dual core pentium pushing 300mbits/sec during peak hours. CPU load 0-1%