well ok if you want you can limit his subnet using a queues and limiting the amout of bandwith he uses up and down stream also u have extra features like liniting p2p connection and al lot of othe stuff! take a look at a module on mikritik called pcc if u have two dsl routers running!
Depending on what kind of installation you want, you have a ton of choices.
The quickest and easiest way is to either use simple queues for each end user, or set up a hotspot and have that make the simple queues for you. This will set a hard limit on the bandwidth that those users can transfer. However, this is done on a per user level and not on a network level. Simple queues are very simple, as soon as a packet matches one of them they fire and are no longer processed.
If you wanted more control being able to identify certain classes of traffic (HTTP, HTTPS, DNS, etc. etc.) and apply certain priorities and limits to those classes of traffic, then queue trees is the way to go. With queue trees you can also set up a network wide absolute limit, and smaller per user limits within that, so you have a lot more control and flexibility with them. However the subject of setting up Queue Trees is a complex one and is not easily covered in a post or two. It will require you playing around with many settings and figuring out the best solution to meet your needs.
