A server system determines, for a group of user sessions assigned to a single modulator, that an aggregate bandwidth for a first frame time exceeds a specified budget for the modulator. The user sessions comprise data in a plurality of classes, each class having a respective priority. In response to a determination that the aggregate bandwidth exceeds a specified budget, the server system allocates a portion of the aggregate bandwidth, including allocating a first portion of the data for a first user session in the group of user sessions and allocating a second portion of the data for a second user session in the group of user sessions, where both the first portion and the second portion are allocated in accordance with the class priorities. The server system transmits the allocated portions of the data for the group of user sessions through the modulator during the first frame time.