Steuerung von Multicastdatensendungen

摘要

A system and method for controlling transmission of a data stream by a server to a plurality of clients in a multicast group. In a first embodiment, one of the clients in a multicast group is designated as a leader. When a service request for transmission of a portion of the data stream is received by the server from any of the clients, the server determines if the service request was from the leader. Responsive to determining that the service request was from the leader, the server broadcasts the portion of the data stream to the clients in the multicast group. Otherwise the broadcasting is deferred. In another embodiment responsive to receipt of the service request for playout of a portion of a video (e.g. a block) from any of the clients in a multicast group, the server determines if a predetermined broadcast criteria has been satisfied. If so the server broadcasts the requested portion to all of the clients in the multicast group. Otherwise, the portion is not multicast to the group and the system is again checked against the broadcast criteria when another service request is received from any of the clients.