Joint Routing and Sketch Configuration in Software-Defined Networking

Traffic measurement is very important for various applications, such as traffic engineering and attack detection, in software-defined networks. Due to limited resources (e.g., computing, memory) on SDN switches, sketches have been widely used for efficient traffic measurement. Meanwhile, multiple independent sketches are required for different application requirements, such as heavy hitter detection and flow size distribution estimation. To avoid the measurement redundancy, we configure which sketch(es) will measure flow on each switch. If traffic measurement is performed on each switch without considering network routing, due to traffic dynamics, it will cause massive measurement overhead on a switch, which may exceed the switch's computing capacity. In this paper, we study the joint optimization of flow routing and sketch configuration in SDNs. We formulate this problem as an integer linear programming and prove its NP-hardness. To solve this problem, we propose a rounding-based offline algorithm and a primal-dual-based online algorithm for different application scenarios. To deal with bursty traffic, we also design an adaptive sampling mechanism for high-fidelity traffic measurement. We formally analyze the approximation performance or competitive ratio of the proposed algorithms. The extensive simulation results show the high efficiency of our proposed algorithms. For example, the online algorithm can improve the network throughput 30% compared with the state-of-the-art.