Basically, the way I read the difference between these two is:
dWRED moves drop probability into the router WAN interface queueing decision process, where CBWFQ simply states a BW reservation for the entire class and drop probability is striclty handled then in the carrier cloud.
CBWFQ seems to be the desired or most used mechanism.
dWRED requires a knowledge of queue size in advance.
I would consider the difference between the two: CBWFQ manages scheduling when dequeuing packets, while WRED manages drops of queued packets. Since they deal with congestion (queued packets) differently, they can be used independently or used together. Both aren't concerned with what happens later downstream (e.g. within carrier cloud), but what happens at some point where packets are queued.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...