Stable and Accurate Network Coordinates

Network coordinates provide a scalable way to estimate latencies among large numbers of hosts. While there are several algorithms for producing coordinates, none account for the fact that nodes observe a stream of distinct observations that may vary by as much as three orders-ofmagnitude. With such variable data, coordinate systems are prone to high error and instability in live deployments. In addition, dynamics such as triangle violations can lead to coordinate oscillations, producing further instability and making it difficult for applications to know when their coordinates have truly changed. Because simulation results demonstrate that network coordinates are capable of providing low cost and sufficiently accurate answers to common queries, it is vital that we develop the ability to obtain similar results in practice. We propose two filters which combined to improve network coordinate accuracy by 54% and coordinate stability by 96% when run on a real, largescale network.