specific content collection to a ptm delivery source it sends out an ssi to each of the client devices the ssi contains a new multicast source address s 45 the client devices 301 306 join the new ptm distribution with the multicast source address and terminate their ptp session when successful the server ensures that the content indexing and the transport object identifier toi designations used by the independent flute sessions are consistent with the ptm session s 46 the client devices continue to download content over the new session a similar sequence of events is followed as shown in fig5 to switch from a ptm session to a ptp session initially a client device may have started download over a ptm session or may have switched to one from a ptp session s 51 server delivery of content with multicast source address over flute s 52 server decides to terminate delivery over ptm and start a ptp session for all active client devices it sends out an ssi informing client devices of the pending termination of the ptm session and instructing them to initiate ptp sessions to continue download a unicast source address is included in the ssi s 53 the client device uses the information provided in the ssi to contact the server or another server and continue its download over a ptp connection using a flute session the.