A method for performing interworking of a standardised wireless communication network (2) and a standardised cellular network (3), comprising the steps of: using a marked service flow over a radio link in the standardised wireless communication network (2) as being dedicated to be sent over the standardised cellular network (3); transporting said marked service flow in a service flow tunnel (13.2) in the standardised wireless communication network (2);mapping said service flow tunnel (13.2) to an inter-network tunnel (13.3) from an element (7) of said standardised wireless communication network (2) to an element (8) of said standardised cellular network (3).