Method of multicast message distribution

A multicast communication node operable for directly communicating with at least one group of interconnected communication nodes in a network wherein the nodes are connected by links and wherein multicast messages are transmitted to selected nodes in said network, said node comprising:

• a node memory including
• a program memory for storing sequences of instructions including a decision, an update process, and a forwarding process,
• a working memory for temporarily storing data and for storing messages to be forwarded, and
• a data base storage including
• a link state packet data base storage for storing a list of all known nodes within a group of nodes with which the node may directly communicate, and
• a forwarding data base for storing lists of links over which messages will be forwarded according to the type of message;
• and
• processor means, connected to the node memory, and capable of accessing said working memory, said program memory and said data base storage, for periodically calculating a unique set of pathways between the nodes in the list of know nodes stored in said link state packet data base in response to said update and decision processes, and for forwarding selected ones of said multicast messages along said unique set of pathways to all of said nodes in the list by distributing said multicast message in response to said forwarding process, said selected multicast messages having ranges including the nodes in said list

In a communication network having a plurality of interconnected communication nodes, each of which is directly communicating with at least one other of said nodes by virtue of a corresponding list of know nodes maintained within each node, wherein those of said nodes which are communicating nodes are capable of transmitting and receiving messages, a method of distributing a multicast message addressed to a corresponding range of nodes in said network, the range of nodes corresponding to said multicast message including the ones of said nodes to which said multicast message is directed, said method comprising the steps of:

• determining, by each of said nodes from its corresponding list of known nodes, at least one group of directly communicating nodes containing the node;
• calculating, by each of said directly communicating nodes in said group, a corresponding unique set of pathways between the nodes in its corresponding group for distributing multicast messages to said directly communicating nodes in said group, said calculating step including the substeps of:
• selecting one of the nodes in each group of directly communicating nodes to be a root node for that group, and
• calculating said unique pathways for each group to connect the root node for that group to every other directly communicating node in that group without causing said pathways to form loops;
• and
• distributing said multicast message to all of said nodes in the corresponding range through said unique set of pathways corresponding to the groups containing the nodes in said range.