Patent ID: 7782795

Claim:
A multicast data communication system comprising: management routers each of which is assigned for a respective one of division multicast domains obtained from dividing an original multicast domain into predetermined divisions, wherein: the management routers share information concerning locations of multicast information sources belonging to the division multicast domains for which the management routers are assigned, respectively, wherein: each of the management routers is determined in such a manner that a data communication apparatus which has a highest priority in a respective one of the division multicast domains is determined as each of the management routers, each of the management routers collects information concerning locations of multicast information sources belonging to its own division multicast domain from data communication apparatuses belonging to the same division multicast domain and delivers the information concerning locations of multicast information sources belonging to its own division multicast domain to the others of the management routers belonging to the original multicast domain, each of the management routers receives from the others of the management routers belonging to the original multicast domain information concerning locations of multicast information sources belonging to respective ones of the division multicast domains of the others of the management routers, so as to obtain information concerning locations of multicast information sources belonging to the entirety of the original multicast domain, and each of the management routers comprises a first table for managing the information concerning locations of multicast information sources belonging to its own division multicast domain, a second table for managing the information concerning locations of multicast information sources belonging to the respective ones of the division multicast domains of the others of the management routers, and a third table for managing information concerning whether each of the others of the management routers is on operation, as well as identification information and an address of each of the others of the management routers.