The below link suggest that there are three major PCQ groups - but it doesn’t really explain what any of them do.
I’ve tried Googling but I’m not having much luck and I thought that perhaps somebody could shed some light on this for me.
Three Major PCQ Groups:
Equal bandwidth for a number of users
Certain bandwidth equal distribution between users
Unknown bandwidth equal distribution between users.
Certain bandwidth equal distribution between users
ISPs for example, at a given time they could have their links almost free, but they offer different plans(For instance 25$ for 20Mbps, 40$ For 40Mbps, etc.. also could include sharing levels). Therefore, ISPs want to control their traffic by groups. Assigning a certain limit for each group.
Equal bandwidth for a number of user
Where all the users will get the same amount of bandwidth, It’s like the previous example, where only one group exist.
Unknown bandwidth equal distribution between users.
I can’t give you a real scenario, because, in order to Mikrotik work properly, it’s suggested to establish the the limit-at and/or max-limit
See: PCQ Rate Examples