Abstract: A packet radio data network has been disclosed, wherein the network comprise at least a gateway node (GGSN), at least one serving node (SGSN) coupled to the gateway node, a plurality of radio access nodes (RAN) coupled to the serving node (SGSN), the packet radio network transporting packet data from an external packet data network, comprising an Internet Service Provider (ISP), to mobile stations (MS) wirelessly attached to radio access nodes (RAN). A given mobile station (MS) issues a membership report message indicating that the mobile station wishes to receive content of a specific multicast group (1), whereupon the gateway node (GGSN) issues a multicast context activation message to the serving node (SGSN) (2). The serving node (SGSN) informs the radio access network (RAN) that the mobile station is joining the respective multicast group (3) and sends a multicast activation response to the gateway node (GGSN) (4).