Methods in an access node for establishing digital media streams between a media server and terminals in a customer premises network are provided. The method includes receiving, from the terminal, a request for establishing a first digital media stream by joining an already established digital media stream; determining transmission resources allocated to the customer premises network; comparing a sum of transmission resources required for the first digital media stream and the already established digital media streams between the media server and the customer premises network with the transmission resources allocated to the customer premises network; and establishing a digital substitution media stream replacing the first digital media stream. The digital substitution media stream is adapted to provide the same content as the first media stream but further adapted to require less transmission resources, so that the sum of transmission resources required for the digital substitution media stream and the already established digital media streams does not exceed the transmission resources allocated to the customer premises network. The substitution media stream is established by joining an already established digital media stream that requires less transmission resources.