BayWatch: Practical Internet-Scale Topology Monitoring with Dynamic Bayesian Estimation

Internet topology monitoring is important for understanding topology dynamics. While a few commercial services have been provided to monitor the specified topology, academic research on Internet-scale topology monitoring still lags behind with two key limitations: 1) topology incompleteness caused by simplified assumption of uniform load-balancing responses (LBR) distribution; 2) low probing efficiency due to the lack of temporal awareness. In this paper, we introduce BayWatch, a practical Internet-scale topology monitoring system that overcomes these limitations based on a Dynamic Bayesian Network (DBN). Leveraging the Markov property of packet forwarding, BayWatch models it as a sequence of state transitions over time within the DBN, so as to estimate the true LBR distribution and predict its temporal evolution. Internet-wide measurement results demonstrate that benefiting from the estimated LBR distribution, BayWatch can discover 2.4×/2.8× more nodes/links than the state-of-the-art algorithm, D-Miner, while the temporal awareness reduces the number of probes by 6.3× with negligible topology completeness loss. Moreover, we demonstrate that BayWatch can help detect anomalies using a real-world network outage event.