Multidestination message passing has been proposed as an attmctive mechanism for efficiently implementing multicast and other collective operations on direct networks. However, applying this mechanism to switch-based parallel systems is non-trivial. In this paper we propose alternative switch architectures with differing buffer organizations to implement multidestination worms on switch-based parallel systems. First, we discuss issues related to such implementation (deadlock-freedom,

more »

... mechanisms, header encoding, and routing). Next, we demonstrate how an existing central-buffer-based switch architecture supporting unicast message passing can be enhanced to accommodate multidestination message passing. Similarly, implementing multidestination worms on an input-buffer-based switch architecture is discussed. Both of these implementations are evaluated against each other as we11 as against a software-based scheme using the central buffer organization. Simulation experiments under a range of traffic (multiple multicast, bimodal, varying degree of multicast, and message length) and system size are used for evaluation. The study demonstrates the superiority of the central-buffer-based switch architecture. It also indicates that under bimodal traffic the central-buffer-based hardware multicast implementation affects background unicast traffic less adversely compared to a software-based multicast implementation. Thus, multidestination message passing can easily be applied to switch-based parallel systems to deliver good collective communication performance.