Patent ID: 7400625

Claim:
A method of transmitting data in a multicast communications network said method comprising: i) defining one or more primary data sets for broadcast transmission over at least one primary multicast communications channel in a communications network; each primary data set comprising data relating to a respective set of two or more secondary data sets associated therewith and provided for transmission over one or more secondary multicast communications channels; ii) repeatedly transmitting (a) said primary data set or sets over said primary multicast communications channel(s) and (b) said secondary data sets over said secondary multicast communications channels; iii) modifying said primary data sets respectively as required in response to modifications to at least one secondary data set in the respective sets associated therewith; iv) repeating step iii) to provide potential recipient(s) of said primary data sets with an indication that at least one secondary data set has been modified independently of said recipient(s) receiving the modified secondary data set or sets, wherein at least one secondary data set comprises at least a description of a media session to be transmitted over said network.