Is it possible?

I just saw a topic which posted few years ago and still no answer yet,I am very curious whether is it possible to achieve,if possible, how?
The question is "access to network 0.0.0.0/0 with rate limit 256,512 or 1024 (rate limit of Hotspot profiles), and network 172.24.24.0/24 with non-rate limit per user. (network topology diagram is attached). Thanks.
Topology.JPG

Yes, I think you can. Queue trees in certain circumstances override simple queues, which are dynamically created by the Hotspot for each user.

First you need to assign packet-marks to the traffic to be exempted:

/ip firewall mangle 
add chain=prerouting src-address=172.16.0.0/16 dst-address=172.24.24.0/24 action=mark-packet new-packet-mark=exempt-up
add chain=postrouting src-address=172.24.24.0/24 dst-address=172.16.0.0/16 action=mark-packet new-packet-mark=exempt-down

Then create queue types that have large rate limits:

/queue type
add exempt-up kind=pfifo pfifo-limit=50
add exempt-down kind=pfifo pfifo-limit=50

And then queues for those packet marks, attached to global-in and global-out so that they fire before the simple queues:

/queue tree
add name=exempt-up parent=global-in packet-mark=exempt-up queue=exempt-up
add name=exempt-down parent=global-out packet-mark=exempt-down queue=exempt-down

I’ve never tried this with anything but PCQ but I hope it works.

I’m learning MT and I think I read something oposite that simple queues take traffic away from queue trees…

It depends on where you attach them to.

I do use a version of the above to run PCQ for Hotspot users instead of simple queues.