Protocol for multicast communication

A software application program for processing data for transmission over a communications network;

• wherein said program is arranged to:—
• define one or more primary data sets for transmission over at least one primary communications channel in a communications network;
• the or each primary data set comprising data relating to a respective set of at least two or more secondary data sets associated therewith and provided for transmission over one or more secondary communications channel;
• transmit said primary data set or sets over said primary communications channel(s);
• modify said primary data sets respectively as required in response to modifications to at least one secondary data set in the respective sets associated therewith;
• and,
• repeat the modifying step 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.

A method of accessing data transmitted over a communications network;

• said method comprising the steps of:—
• i) receiving at least one primary data set transmitted over a primary communications channel in a communications network, the or each primary data set comprising data relating to two or more secondary data sets associated therewith and provided for transmission over one or more secondary communication channel;
• ii) processing the or each primary data set to determine whether said data set or sets indicate changes to any one or more of said secondary data sets;
• and
• iii) receiving said secondary data set or sets over said secondary communications channel or channels in response to changes to said secondary data set or sets being determined.

A software application program for processing data for transmission over a communications network;

• wherein said program is arranged to:—
• receive at least one primary data set transmitted over a primary communications channel in a communications network, the or each primary data set comprising data relating to two or more secondary data sets associated therewith and provided for transmission over one or more secondary communications channels;
• process the or each primary data set to determine whether said data set or sets indicate changes to any one or more of said secondary data sets;
• and
• join the or each secondary communications channel to receive said secondary data set or sets over said secondary communications channel or channels in response to changes to said secondary data set or sets being determined.