Video/audio network

A packet-based data network comprises: a packet-based network switch; a plurality of packetised data sources coupled to the network, the packetised data comprising at least one of audio data or video data; at least one destination, being a data handling device for handling data from the packetised data sources, coupled to the network; and a network control arrangement coupled to the network, the network control arrangement being arranged to provide virtual circuit-switched connections for transfer of packetised data from sources to destinations via the network switch by: a) assigning multicast group identifiers to the sources, so that the sources launch packetised data onto the network as multicast data packets identified by the multicast group identifiers; and b) instructing a destination to issue a request to the network switch to join the multicast group of a source so as to receive data packets from that source.