Traffic Shaping – Using tc Filter to Catch All Traffic

If I understand htb correctly, then the rate is "guaranteed". This means you have ideas about the rate of the "realtime" traffic. Only if this rate is exceeded, it will borrow. If several classes want to borrow, the prio should kick in. The guaranteed rates should add up the physical limit. Otherwise it's too much of a hassle.

IMHO, Case A will never really work since you need to have priority or rate-limiting at the root level. The priorities/rates in the different segment don't know anything of each other and will be handled equally.

The thing you probably want is: Put the "rate" for low and normal prio to 0 or close to it and add "ceiling" for the rest of the bandwidth, for high prio you guarantee a rate of 100% of the physical.

i think that you should not put 64k users with upstream and downstream classes and filters for each of them on the same interface. You can repeat the handlers for each interface you have, so add more interfaces. You will need a incredible work/server/NIC to have this things. If the server crashes, you will have 64k users offline (and it will crash easily with that amount of traffic). Don't forget that EACH packet that goes through your network card will be checked and classified by a filter and sent to a class to be queued. This is a lot of work for a NIC of an ISP gateway with 64k customers. Mainly with all the video stream that we have nowadays (which is hard to queue properly).