The Internetworking of Connectionless Data Networks over Public ATM: Connectionless Server Design and Performance

The transport of connectionless data is necessary for the compatibility of emerging wide area ATM networks with existing computer networks. This paper investigates the design and performance of a virtual connectionless network overlayed on top of cell-based connectionoriented ATM networks. The virtual connectionless network is made possible by utilizing connectionless servers. Two packet forwarding techniques used by connectionless servers are examined. Forwarding connectionless packets in a cell-by-cell manner (streaming mode) is shown to result in lower packet loss and end-to-end delay than packet-by-packet forwarding of connectionless data (reassembly mode). A design and implementation are presented for a streaming mode connectionless server capable of a maximum throughput of 100 Mbps. This research is supported by grants from the University of California MICRO program, Nippon Steel Information and Communication Systems Inc. (ENICOM), Hitachi Ltd., Hitachi America, and Tokyo Electric Power Company.