CeGen: A Cost-Effective Probe Generation Scheme for Rule Verification in SDN

Rule verification is a prevalent way to troubleshoot network issues, which needs to generate a proper set of probes to exercise the rules. Existing probe generation schemes either determine a minimum number of probes using end-to-end probing, whose computation time is too long to handle rule dynamics, or generate and verify the rules one by one in a streaming way using per hop probing, which produces many more probes. In this letter, we propose CeGen, a cost-effective probe generation scheme that explores the possibility of generating a small number of probes leveraging per hop probing to strike a balance between the computation time and the number of probes. By modeling the network as a directed acyclic graph carrying state information, a small number of probes could be achieved by traversing the graph. We evaluate CeGen’s performance and compare with two solutions: ATPG and Monocle, on two data sets. The result shows CeGen could complete the probe generation in a short time while maintaining a small number of probes.