The helical switch: a multipath ATM switch which preserves cell sequence

The paper presents a new cell switching architecture for ATM-based networks. The proposed helical switch is a multistage interconnection network which implements the self-routing technique with efficient buffer sharing. Although the switch may route cells along multiple paths, the connection-oriented mode required by the ATM-based network is supported. Cell sequence integrity is guaranteed by introducing a virtual helix which forces cells routed along different paths to proceed in order and fill the internal buffers uniformly. The performance of the helical switch is investigated under uniform and nonuniform traffic patterns. Unlike single-path multistage networks such as buffered banyan networks which can degrade significantly under nonuniform traffic, the helical switch is shown to be quite robust with respect to nonuniform traffic conditions