Optimal Nonblocking Multipoint Virtual Circuit Switching Optimal Nonblocking Multipoint Virtual Circuit Switching

Many multipoint virtual circuit switching systems have been proposed for use in ATM networks. The inherent exibility of ATM networks and the desire to use them for a wide range of diierent applications makes it impractical to rely upon statistical traac models, motivating a renewed interest in nonblocking networks. While the various multipoint architectures can all be conngured to be nonblocking, for most, the cost quickly becomes prohibitive. We examine the complexity of several multipoint switch architectures, taking into account the switching network, the memory needed for routing and the eeort required to create or modify a virtual circuit. We show that a simple nonblocking architecture, based on the concept of cell recycling, achieves optimal complexity. This architecture exempliies a class of networks which we refer to as reroutably nonblocking.