Device and system for multicast communication

A first multicast router forwarding a multicast data packet comprising:

• a unit for storing multicast request information including information required to receive multicast data packets;
• a unit for monitoring requests from a receiving terminal to receive multicast information sent by a multicast delivery server and obtaining the contents of a request when the request is detected, wherein the receiving terminal does not support multicast communication;
• a unit for generating and sending a join group request to a second multicast router interposed between the multicast delivery server and the first multicast router including instructing the second multicast router to route multicast data packets based on the monitoring results, wherein the join group request is not generated if at least one receiving terminal is already subscribed to receive multicast information sent by the multicast delivery server;
• and
• a unit for receiving, via the second multicast router, data packets multicast from the multicast delivery server corresponding to the group join request, setting a destination address of the data packet to address information of the receiving terminal based on the monitoring results, and sending the received data packet to the receiving terminal.

A service system providing information using multicast communication comprising:

• a multicast delivery server multicasting data packets containing information to be provided;
• and
• a multicast communication device transferring multicast data packets to a receiving terminal that does not support multicast communication, which device includes:
• a unit for storing multicast request information including information required to receive multicast data packets;
• a unit for monitoring requests from the receiving terminal to receive multicast information sent by the multicast delivery server and obtaining contents of a request if the request is detected;
• a unit for storing received multicast delivery server information sent by the multicast delivery server, the multicast delivery server information including an address of the multicast delivery server and addresses of receiving terminals subscribing to multicast groups associated with the multicast delivery server;
• a unit for comparing contents of the request obtained by the unit for monitoring with the multicast request information stored in the unit for storing multicast request information;
• a unit for generating and sending a join group request to a multicast router interposed between the multicast delivery server and the multicast communication device including instructing the multicast router to route multicast data packets based on results of the comparison performed by the unit for comparing contents of the request when the request is detected, wherein the join group request is not generated if at least one receiving terminal is already subscribed to receive multicast information sent by the multicast delivery server;
• and
• a unit for receiving data packets multicast from the multicast delivery server and forwarding the data packets to the receiving terminal.

A service system providing information using multicast communication comprising:

• a multicast communication device including:
• a unit for storing multicast request information including information required to receive multicast data packets;
• a unit for monitoring requests from a receiving terminal that does not support multicast communication to receive multicast information sent by a multicast delivery server and for obtaining contents of the requests when the requests are detected;
• and
• a unit for sending multicast delivery requests based on the communication monitoring results, wherein the multicast communication device compares each multicast delivery request to multicast service management information, the multicast service management information including service availability information associated with multicast delivery services, and wherein a multicast delivery request is not sent in response to a request from the receiving terminal if the request from the receiving terminal is received outside of service availability indicated by the service availability information of the multicast delivery server;
• and
• a data forwarding device receiving data packets multicast from the multicast delivery server and sending the data packets to the receiving terminal.

A method in a multicast communication device for providing a receiving terminal that does not support multicast communication with information sent via multicast communication by a multicast delivery server comprising the steps of:

• storing multicast request information including information required to receive multicast data packets;
• monitoring requests from the receiving terminal to receive multicast information sent by the multicast deliver server;
• obtaining the contents of the request when the request is detected;
• comparing the contents of the request from the receiving terminal with multicast delivery server information sent by the multicast deliver server and stored on the multicast communication device, the multicast delivery server information including an address of the multicast delivery server and addresses of receiving terminals subscribing to multicast groups associated with the multicast delivery server;
• generating and sending a join group request to a multicast router including instructing the multicast router interposed between the multicast delivery server corresponding to the join group request and the multicast communication device to route multicast information based on the monitoring results, wherein the join group request is not generated if at least one receiving terminal is already subscribed to receive multicast information sent by the multicast delivery server;
• receiving information multicast from the multicast delivery server;
• and
• sending the received information to the receiving terminal.