A high-performance prototype 2.5 Gb/s ATM switch for broadband applications

A prototype 2.5 Gb/s ATM (asynchronous transfer mode) switch fabric was developed for flexible broadband applications. The prototype configuration supports multiple standard line card interfaces. Employing the concept of hierarchical multiplexing, the ATM cells are extracted from the payload of these SDH (synchronous digital hierarchy) signals and multiplexed inside the fabric to an internal equivalent cell rate of 2.5 Gb/s. Routing is done on a cell-by-cell basis according to the cell header address information. The core fabric of the switch is therefore a 2.5-Gb/s ATM switch. The fabric is designed, using the theory of the growable switch architecture, to guarantee the best possible delay-throughput performance for arbitrary traffic distributions for independent inputs. In this prototype implementation, physical size, physical growth, power consumption, protection switching, maintenance, and reliability are optimized. The core 2.5 Gb/s fabric prototype can grow from 8×8 (supporting up to 128 STM-1 interfaces) to larger sizes (e.g. 64×64, supporting up to 1024 STM-1 interfaces). Considerations for substantially larger switch sizes are also taken into account. The initial prototype and its evolution to larger switch dimensions are discussed