Collaborative Traffic Measurement Using Sketches for Software Defined Networks

In a software-defined network (SDN), statistics information is of vital importance for different applications, such as traffic engineering, flow rerouting, and attack detection. Since some resources, e.g., ternary content addressable memory, SRAM, and computing capacity, are often limited in SDN switches, traffic measurements based on flow tables or sampling become infeasible. Sketch, a hash-based data structure, monitors every packet with fixed-size memory to provide a feasible approach of traffic measurement, but there exists a tradeoff between accuracy and memory. Currently, many efficient sketch algorithms have been designed to different purposes, but they focus on the performance and applications of one single sketch. In this paper, we present a scheme to reduce redundant flow statistics collected by sketches of different SDN switches. The proposed scheme could reduce measurement overhead in sketches, obtain more accurate estimate flow size, and find the elephant flow precisely.