Abstract: The invention concerns a method of providing resource admission control to packet flows (11, 12, 50) associated with sessions in a communication network (2), and an access controller (21, 22) to execute this method. The communication network (2) handles packets according to priority levels assigned to the packets. The priority levels comprise at least a first and a second priority level wherein the first priority level is higher than the second priority level. First, a packet flow (12) associated with the new session is identified when packets of the packet flow (12) enter the communication network (2). Preferably, the new session is a real-time session. The second priority level is assigned to the identified packet flow and the packet flow (12) is handled according to the second priority level within the communication network (2). A congestion level is measured in the communication network (2).