Low-power system-level design of VLSI packet switching fabrics

System-level design of packet switching fabrics focuses on performance metrics and rarely considers the physical requirements that are usually addressed later at the circuit-level. However, low-power dissipation has become a major requirement in such fabrics dictated by the requirements of emerging applications and by the recent advances in fabrication and VLSI technologies. This paper proposes a framework for system-level design of packet switching fabrics that integrates performance specifications along with physical requirements and constraints. Moreover, realistic traffic models are used to derive the transition activity and the packet arrival and departure events needed for power estimation. Physical requirements are defined by an architectural model for power dissipation based on the stochastic traffic model, models for silicon area, chip count, and input-output pins, which provide a complete system-level specification of the fabric. Performance constraints are also derived from the stochastic traffic model. This framework formulates and solves the power optimization problem subject to those physical and performance constraints as an integer nonlinear optimization problem. The results obtained emphasize the importance of traffic-driven system-level optimization and show the efficiency of this framework as a system-level design space exploration tool.