The invention relates to a method and a system for establishing communication relations (stream1, stream2, stream3) via a communication medium, at least one communication relation (stream1, stream2) being established via said communication medium. According to the invention, information on queries for establishing one respective communication relation (stream1, stream2, stream3) is recorded, and, depending on the recorded information, at least one of the already established communication relations (stream1, stream2) is terminated or maintained. The information recorded can be e.g. the query times (ti), the interval lapsed between two queries being used to infer the type of communication relation (stream1, stream2, stream3). According to the invention it is for example possible for short intervals to infer queries for IP-TV data streams and previously established communication relations (stream1, stream2) are directly terminated in order to save band width.