Experimenting with buffer sizes in routers

Abstract

Recent theoretical results in buffer sizing research suggest that core Internet routers can achieve high link utilization, if they are capable of storing only a handful of packets. The underlying assumption is that the traffic is non-bursty, and that the system is operated below 85-90% utilization. In this paper, we present a test-bed for buffer sizing experiments using NetFPGA [2], a PCI-form factor board that contains reprogrammable FPGA elements, and four Gigabit Ethernet interfaces. We have designed and implemented a NetFPGA-based Ethernet switch with finely tunable buffer sizes, and an event capturing system to monitor buffer occupancies inside the switch. We show that reducing buffer sizes down to 20-50 packets does not necessarily degrade system performance.