In this example we will use QoS (Bandwidth Throttling) to rate limit downloads after they exceed 50MB of transferred data. An example classifier is below. Ports 80 and 443 are listed as the source because we are identifying traffic that a user is downloading from the Internet. The Session Min:Max is entered in bytes and, in this example, will match bytes 1 through 52,428,800 which equals 50MB.
A second classifier is then created that identifies the same traffic but without a session size specified. This classifier is for all traffic that does not match the previous classifier such as a download that has exceeded 50MB.
In the Inbound section of the QoS configuration you would then set up rules as illustrated below. QoS rules are evaluated from top to bottom so the order of the rules is important for this method. In this example the first 50MB of a download would match the first rule and would be allowed to use up to 100% of the available bandwidth. After the first 50MB is downloaded the traffic will no longer match the first rule but will match the second rule in the list. The second rule has the maximum bandwidth set to 25% instead of 100% so the download will now be rate limited to 25% of the available bandwidth.