Analysis of a flow control system for a combined input-crosspoint buffered packet switch

A flow control mechanism is used in combined input-crosspoint buffered (CICB) switches to avoid buffer overflow and underflow. Credit-based flow control is widely used in CICB switches to reduce the required crosspoint-buffer size. For simplification, we analyze an flow control mechanism with active queue management (AQM) and a proportional controller. We show that the flow control mechanism is stable for small crosspoint buffer sizes and non-negligible round-trip times. In addition, we observe the effect of an input shaper combined with a proportional controller. We show that the input shaper reduces the response time of the flow control mechanism.