Abstract: In a multicast delivery system, A delivery server enciphers delivery data by using a current use cipher key to generate enciphered data and transmits a multicast packet containing the enciphered data and a current use key identifier indicative of a pair of the current use cipher key and a current use decipher key as current use keys. A key management server holds as a current use key data, a set of the current use decipher key and the current use key identifier, and transmits a set of the current use decipher key and the current use key identifier as a current use decipherment key data in response to a current use key data request.

Abstract: A data transmission system includes a plurality of dynamic route control units each disposed for one of a plurality of interfaces provided in the data transmission system. The route control data prepared by the dynamic route control units are combined by a specified dynamic route control unit to obtain in-system route control data, which is delivered to all the dynamic route control units. Each dynamic route control unit calculates costs for the routes between the own system and other data transmission systems based on the in-system route control data and new route control data received.

Abstract: A multicast packet transfer system includes a first packet transfer apparatus and a second packet transfer apparatus. The first packet transfer apparatus transmits transfer packet data relating to an IP header and a UDP header of a multicast packet when the multicast packet is received, rewrites a header section of the multicast packet to produce a unicast packet, and transmits the unicast packet. The second packet transfer apparatus receives the transfer packet data and the unicast packet, and reproduces the multicast packet based on the received unicast packet and the received transfer packet data.

Abstract: Multicast packet transferring apparatus and system are provided in which a multicast transferring path is established between different domains.

Abstract: A data transfer method between a plurality of data transfer apparatuses, is attained by establishing peers between the plurality of data transfer apparatuses to store the established peers in a transfer route configuration data table as transfer route configuration data in each of the plurality of data transfer apparatuses; and by transferring a reception data to specific ones of the plurality of data transfer apparatuses based on the transfer route configuration data in each of the plurality of data transfer apparatuses.