Mark Allen Pashan

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.<<ETX>>

An ATM cross-connect system for broadband trials and applications

A prototype ATM cross-connect system has been developed by AT&T in joint collaboration with NTT. The system is intended for flexible broadband trials and service applications. The system supports multiple standard line card interfaces, e.g. 155 Mb/s STM-1, 622 Mb/s STM-4c and 2.5 Gb/s STM-16. These different interfaces can be installed interchangeably into the same physical slots in an arrangement called universal line card slots. ATM cells extracted from different incoming SDH signals are multiplexed to 2.5 Gb/s inside the system for internal cell switching in a core fabric (hierarchical multiplexing). The ATM cross-connect system is based on a growable switch architecture that starts with an 8/spl times/8 main frame with a shared-memory switch delivering the best-possible delay-throughput performance and optimal buffering to minimize the cell loss probability. With virtually no effect on performance, the core fabric can be expanded to 32/spl times/32, yielding a total system capacity of 80 Gb/s. Further growth to substantially larger sizes is possible. Service-oriented features include 1+1 hitless protection switching, in-service upgrade and compact physical size.<<ETX>>

A Prototype Growable 2.5 Gb/s ATM Switch for Broadband Applications

A prototype 2.5 Gb/s ATM switch fabric has been developed for flexible broadband applications. The prototype configuration supports multiple standard line card interfaces, e.g., STM-1 (155 Mb/s), STM-4c (622 Mb/s) and STM-16c (2.5 Gb/s). The ATM cells are extracted from the payload of these SDH signals and are multiplexed inside the fabric to an internal equivalent cell rate of 2.5 Gb/s. Routing is done subsequently on a cell-by-cell basis according to the cell header address information (VPI and/or VCl). 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 guaranteeing the best possible delay-throughput performance for arbitrary traffic distributions for independent inputs. In this prototype implementation, careful considerations have been given to optimize various aspects such as physical size, physical growth, power consumption, protection switching, maintenance and reliability. The core 2.5 Gb/s fabric prototype can grow from 8 x 8 (supporting up to 128 STM-1 interfaces) to larger sizes (e.g., 64 x 64, supporting up to 1024 STM-1 interfaces). Considerations for substantially larger switch sizes have also been taken into account in the design. Descriptions of our initial prototype and its evolution to larger switch dimensions are discussed.