Hi, After defining the policy maps , how does one decide where and in which direction should the policy be applied ?
Outbound on your CPE router, and make sure that the service provider does the same on their PE router.
Actually you can do classification input on your Eth inteface.
Outbound on the Spoke serial interface would guarantee 20kbps of traffic to Hub. To guarantee the return traffic you should apply it outbound at the HUB to each spoke site as well.