An Improvement of Multicast Probing Route Design for Locating Deteriorated Links

Cloud computing and content delivery networking have increased demand for centrally managed networks with dynamic and flexible traffic engineering that are based on OpenFlow. In such systems, detecting and locating deteriorated links is necessary to maintain a high network service quality. Our previous work suggested a measurement framework that merely relies on standard OpenFlow functions and can quickly locate all high-loss links. The load on the data-plane and control-plane incurred by the measurement can be reduced by combining an active measurement by probing multicast packets along a designed route and a passive measurement by collecting flow-stats of the probing flow at selected switch ports in an appropriate sequential order to access switches. In particular, the measurement overhead (the number of switches accessed before locating all high-loss links) can be decreased while maintaining a high level of accuracy with a specific length path by creating the measurement route based on the backbone-and-branch tree (BBT) route scheme. Since a longer path will reduce the number of accesses to the switches, the path length is better to be long unless it exceeds the maximum allowable length depending on the targeted link loss rate to detect. However, there was no such control to make the path length optimal. Therefore, in this paper, we proposed a method to optimize the route scheme with a limited length of paths for probing packets. The numerical simulation shows the effectiveness of our proposal.