An extension to an existing method for building multiphase protocols is presented. One of the limitations of the former method is a stringent restriction on the validity of phases. Consequently, the protocols built by this method must run in a noiseless environment or rely on other protocols for reliable transport. Another restriction is a rigid requirement on the selection of the points that connect different phases. The presented method either minimizes or eliminates the above restrictions. It enables a multiphase protocol to deal with message corruption and loss, and provides a less restrictive way for phase connection. It also maintains the advantages of the existing method in allowing a multiphase protocol to be constructed in an easy and modular way.>

A high-performance copy network, which supports multicast fast packet switching in the broadband integrated services digital network (B-ISDN), is proposed. The network uses a banyan multistage interconnection network (MIN) with speedup and requires no intermediate buffering. It has been recognized that the copying process is, in general, a difficult one. Two important design issues, namely, obtaining multiple copies of packets and assigning destination addresses of the copies, are pursued. A solution to these issues by developing a novel two-phase copying process is presented. An analytical performance model with a special structure of Markov chains, called a branching process, is formulated. Numerical results using this model for a constant number of copies as well as for a geometrically distributed number of copies show that the proposed copy network achieves very low packet blocking probability. Simulation results are provided to confirm the analytical model.>