bandwidth and avr queries

hello, I have a question for the management of bandwidth and I have not handled much, I have a total link of 25 mb and I want to control the consumption of bandwidth, some articles say that rate classes list is used, and others with banwidth controllers: policies, I would like to know if it is the same or different things

additionally they are reporting that there is slowness I want to see the consumed bandwidth and I see in the avr, the reports of traffic in bits of the last hour and I see that they do not reach they do not reach 25, however in the performance reports> througputh I see that there are 30 mb peaks, I don't understand what information should I use to guide me