ATM SUPERPACKET NETWORK FOR RESPONSIVE MEGA-DATA DELIVERY SERVICE

This paper shows new techniques to construct a service network which r ealizes responsive large-size data transmission for widely distributed mass users. We set our service target as transferring mega-byte scale data from a server to a client within one second. ATM is recognized a s a powerful technology with which to construct a wide area network in frastructure that supports multiple bandwidth services. Our fundamenta l principles in developing such a service network are as follows: a) T he bandwidth sharing mechanism should be of the best effort rather tha n resource reservation type. This is because only best effort schemes remove bandwidth reservation/release overheads. b) More than a 100 Mb/ s data transmission rate should be supported throughout data transfer, c) Data transfer should be completed within the round trip through th e network (or a small multiple thereof). This is necessary to minimize the effect of transmission time in large-scale networks. d) The user network interface should be simply defined to allow independent evolut ion of both network and terminal technologies.; e) Congestion control must block the spread of congestion within the network. Based on these principles, we propose the ''ATM superpacket network (ATM-SN)'' as th e service network to realize our target service. Key techniques are as follows. (I) Best effort and cut-through transmission of superpackets whose length reaches ten mega-bytes. (2) Network nodes with large-cap acity buffer memories that prevent superpacket collisions. (3) Superpa cket admission control at network nodes to prevent cell overflow. (4) Superpacket-based congestion control. Our proposal assumes the existen ce of a high-quality ATM infrastructure that can provide a large bandw idth with a high-quality DBR cell transmission capability (cell loss r atio is less than 10E-7) and small bit error ratios (less than 10E-10) . First, we detail our proposal of the ATM-SN. Next, we propose a supe rpacket-based congestion control technique coupled with a simple Usage Parameter Control function. We then show the evaluation results of th ose key techniques to confirm the effectiveness of the superpacket net work.