Multistage shuffle networks with shortest path and deflection routing for high-performance ATM switching: the closed-loop shuffleout
M. Dècina, Paolo Giacomazzi, Achille Pattavina · IEEE Transactions on Communications · 1994
A new class of switching architectures for broadband packet networks, called shuffleout, is described and analyzed. Shuffleout is basically an output-queued architecture with a multistage interconnection network built out of unbuffered b/spl times/2b switching elements. Its structure is such that the number of cells that can be concurrently switched from the inlets to each output queue equals the number of stages in the interconnection network. The switching element operates the cell self-routing adopting a shortest path algorithm which, in case of conflict for interstage links, is coupled with deflection routing. The basic version of this architecture is called open-loop shuffleout. This paper describes the closed-loop shuffleout architecture with 2/spl times/4 switching elements in which cells that have crossed the whole interconnection network re-enter the network as long as they are not successfully routed to the addressed switch outlet. This result is accomplished by adding to the basic open-loop structure recirculation paths so that each packet can cross several times the interconnection network. Two different solutions are proposed to implement such functionality, the buffered closed-loop shuffleout and the expanded closed-loop shuffleout architecture. Both these solutions aim at reducing the number of stages in the network, compared to the open-loop structure, so as to reduce the complexity of the switch internal wiring and to simplify the output queue interface.>