Output buffered ATM switch with frame discard

Among the current high-speed packet switching system proposed during the last years, switches with output buffering have been proven to give the best delay/throughput performance. The Knockout switch belongs to this category and its design is based on the Knockout principle. However, most of the higher-level data units (frames) are too large to be carried in a single packet and must be segmented for switch delivery. If one packet in a frame is discarded by the Knockout principle then the frame will be discarded in the destination. To get a better application-level quality of service (QoS) at the same packet loss rate, some sophisticated loss mechanisms such as early frame discard schemes (i.e., early packet discarded, EPD) have been proposed. We study the performance of early packet Knockout in an output buffered ATM switch by simulation. This paper describes the simulation model and parameters we used and analyzes the results. The results show that the output buffered ATM switch with early packet Knockout could produce a better application-level QoS than a switch without the scheme