Ultra-low transmission latency for sporadic network traffic

A method for transmitting sporadic data stream over a packet switched network, said network carrying out further a transmission of priority data transmission within scheduled successive priority time windows,

• wherein the transmission of the sporadic data stream is preceded by a transmission of a reservation frame including information related at least to a timing for transmitting the sporadic data stream outside from said scheduled priority time windows, the reservation frame follows a predetermined path over the network that matches a predetermined path of the sporadic data stream to trigger an opening of a transmission window in at least one output port of transmitting entities in the path thereby dynamically reserving the transmission window for the sporadic data stream.