What I need actually just to put some rules for all users rather then one queue for each users.
Let say our client ip address is 192.168.4.0/24
How to make some rules (perhaps using pcq or cbq with mangle or others), so each users will get the same limit-at, max-bw and if possible burst ?
in limit-at using PCQ you have to set available BW for user group you want to limit, so if you have 10 users and 1MBps available BW, then each user (if all users are online) will get 100KBps (100KBps*10 = 1MBps)
and read those links that sergejs provided, there is everything you need to know.