| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1999: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
Reliable multicast has got much attention as a next generation's technology on information delivery systems. It guarantees the information deliveries without errors on large-scale multicasting.
However, reliable multicast methods have two major problems. One is that they cannot work well as the number of receivers increases when only the sender retransmits lost packets to all of receivers simultaneously. This retransmission method is called the global recovery. The other is ACK implosion. Network congestion occurs by concentration of many returned ACKs.
Local recovery system has been presented to cope with these problems. It can localize the influence of retransmissions by grouping nodes. Several ways of retransmissions, for instance using unicast, multicast, and subcast, have already been proposed.
This study focuses on these retransmission methods with local recovery systems since they must be the better solutions for large-scale multicasting on worldwide network. The appropriate retransmission method, however, may depend on network topologies. This paper therefore compares local-recovery-based retransmission methods and finds the suitable one for typical kinds of network topologies ; star, ring, delta-star, and Waxman's model which represents current Internet topology. The suitable network topology for the reliable multicasting is also discussed from the viewpoint of network construction cost.
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