Ntt Docomo, Inc.

Harunobu Fukazawa

Ken Igarashi

So Ishida

A communication system () is provided with URs (to) and a source terminal (). The URs (to) include: entry holders (to) for holding forwarding addresses; message processors () for registering the addresses of other URs, the addresses being associated with a source terminal address and a multicast group address, in the entry holders (to) as the forwarding addresses; message providers () for providing the source terminal address with join request messages which request the addition of the addresses of the URs to sending addresses. The source terminal () includes: an entry holder () for holding a sending address; and a message processorfor registering the addresses of the URs (to) in the entry holderas sending addresses based on the join request messages.

Communication system, multicast-capable router, transmitter terminal, receiver terminal, and communication method

A receiving device which received segments out of sequence identifies a lost segment among the segments to be received successively and transmits an acknowledgement including the number of lost segments as an advertised window size. By substituting either one of a transmitting device or a receiving device included in a communication system with a transmitting device or a receiving device of the present invention, a segment retransmission method according to the present invention is achieved. The present invention thus allows a conventional communication system to perform the lost segment retransmission of the present invention.

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Yokohama, Japan

Harunobu Fukazawa