I wonder if HQF is new feature or is it just new name for old features?!
I mean hierarchical qos policies existed before HQF right ?!
Is is not a 100% new feature; it has a different name so you know when something changed, its scope being to provide a unified QoS experience across multiple platforms. However, it did add some new features and also changed some old features:
Good luck with your studies!
It was introduced in 12.4(20)T. A lot of stuff is similar to CBWFQ but HQF does not do fair queuing by default. Also you have the possibility to create different levels of prioritization. With CBWFQ if you have a LLQ and several classes then they all go into the same LLQ.