Efficient Flow Recording with InheritSketch on Programmable Switches

Several studies have been proposed to deploy the flow recording (i.e., flow size counting and sketching algorithms) on programmable switches for high-speed processing, helping network management tasks like scheduling. Although programmable switches provide a remarkable packet processing speed, they are of compact resources and follow a restrictive pipeline programming. To fit these limitations, current algorithms either sacrifice the recording accuracy or harm the switch throughput. In this paper, we propose InheritSketch for further improvement. InheritSketch utilizes a separation counting fashion, which is memory-efficient for compact switches. It accurately records the more valuable heavy hitters in the large key-value counters (i.e., the primary table), while only sketching non-heavy flows in the small sentinel table. With the recording ongoing, InheritSketch intelligently summarizes the historical recording experience as the basis for flow inheritance. That is, flows with the same IDs as the previous heavy hitters are regarded as new heavy hitters, being recorded in the primary table. To correct some incorrect inheritance, we also propose the flow rebellion, which promotes flows of large sizes but wrongly stored in the sentinel table to the primary table. InheritSketch is also helpful in applications like differentiated scheduling. We compare InheritSketch with six previous recording algorithms on three public traffic datasets, and prototype InheritSketch on a commodity P4 switch. The results demonstrate that InheritSketch reduces the recording errors by at most ∼7×, and that InheritSketch only consumes 10% of hardware resources on the switch.