Patent ID: 6973081
Filing Date: 2005-12-06
Classification: H04L

Abstract:
1. A communications system providing a seamless switch from initially receiving data over a unicast session to receiving said data over a plurality of multicast sessions, said communications system comprising: an electronic device configured to receive said data over said unicast session, said electronic device responsive to a signal to join said plurality of multicast sessions, said electronic device identifying as a joinable multicast session one of said plurality of multicast sessions currently not transmitting said data and which will not be transmitting for at least a sufficiently long time, said electronic device joining said joinable multicast session, said electronic device joining the remaining of said plurality of multicast sessions when said electronic device starts receiving said data over said joinable multicast session, wherein said sufficiently long time is longer than the sum of the time required for said electronic device to join said joinable multicast session and the time required for said electronic device to request a server to stop transmitting said data over said unicast session at the next multicast synchronize point; and to transmit a request to stop transmitting said data over said unicast session at a next multicast synchronize point.