Dynamic buffer allocation for quality of service provision in combined input and crosspoint buffered switches

The Combined Input and Crosspoint Buffered (CICB) switch plays a crucial role in providing Quality of Service (QoS) in interconnection networks, which is the foundation for high-performance distributed computing. Crosspoint buffer space is a scarce resource in CICB switches that must be utilized efficiently. Although dynamic sharing typically improves crosspoint buffer utilization, it also introduces new challenges to QoS provision in CICB switches. In this paper, we address the problem of improving crosspoint buffer utilization while providing sufficient QoS guarantees to various traffic flows in CICB switches. We propose a dynamic buffer allocation scheme that enables sharing crosspoint buffer space dynamically between flows with different QoS requirements. We also develop an analytical model for evaluating the performance of this buffer allocation scheme. Our analysis shows that if buffers are shared within a certain threshold, the dynamic buffer allocation scheme improves crosspoint buffer utilization without sacrificing delay performance. Our analysis in this paper also quantifies the tradeoff between crosspoint buffer utilization and guaranteed delay performance.