Some ISPs are doing QoS based on traffic type (online streaming), such as Comcast and Cogent. Why don't they reset IP DSCP at the edge so it is not as obvious that they are doing some kind of traffic shaping? Most CPEs are going to ignore DSCP anyway.
Any insight on how ISPs usually implement this type of QoS? I am thinking at exchange point, source IP (content networks) based mapping. What am I missing here (the linecard is going to be pretty expensive...on platform like ASR9K)?