Which two of these are differences between traffic policing and traffic shaping？（）

A.with traffic shaping，a router stores excess traffic in packet buffers until bandwidth is available again
B.with policing you can tune the buffer usage for traffic exceeding the specified CIR
C.with shaping you can tune the buffer usage for traffic exceeding the specified CIR
D.shaping should only be applied for ingress traffic，policing only for egress
E.policing uses a token bucket algorithm，shaping uses an SPD algorithm