Pablo,
I am not sure tools but I have seen most cases where they will just use a feature from the IOS such as ISG, an SCE implementation depending on geographical location or just plain old QoS. It will all depend on what kind of service is given and the platform. Sometimes when the service is configured on the ISP end one of the steps is to specify how much bandwidth a subscriber will have access to.
If you are not the ISP and you are just a CPE then you could just go with QoS.
