Method of transmitting service information, and radio system

The invention relates to a radio system which transmits packet traffic and to a method of transmitting service information flexibly between a network part and a terminal in a radio system which transmits packet traffic and in which a connection set-up process is activated by means of a session management arrangement when a connection is established between the terminal and the network part. When service information is transmitted between the network part and the terminal, the party needing service activates the connection set-up process and during activation the party needing service indicates the need for service information and the quality of service with a message. The party providing service responds with one or more messages which include service information. The connection set-up process is finished without establishing a connection. This way radio path resources can be saved.