a method for switching traffic during real time stream transmission depends on a network side device to identify the start and end of the stream transmission , and to perform a switching between best effect traffic and the streaming traffic . the network side device can be a stream media content server , a serving general packet radio service support node or a gateway general packet radio service supporting node of a core network . a system for switching traffic during a real time stream transmission , a content server for real time stream transmission , a ggsn for real time stream transmission , an sgsn for real time stream transmission are also disclosed .