A Unified Network “Coordinate” System for Bandwidth and Latency

Abstract Network coordinate systems, such as GNP and Vivaldi, provide virtual positions for networked hosts, which en- able the hosts to connect to nearby peers, find the closest server, or organize themselves in a topologically-aware manner. Current network coordinate systems, however, only use latency to compute the positions, leaving out an important network metric—namely,bandwidth. In this paper, we present a unified approach that pro- vides virtual positions based on both bandwidth,and la- tency. The key intuition is that network,latency and bandwidth are approximate tree metrics, that is, a set of distances that can be embedded,in a tree. We first ar- gue based on intuition and analysis of three real-world datasets why bandwidth,and latency can be represented as tree metrics. Then, we present Sequoia, an accurate and light-weight system that provides virtual network po- sitions by embedding,bandwidth,or latency on trees; the network positions computed,by Sequoia are as easy to use as a set of coordinates. Finally, we present an evalua- tion based on the three datasets showing that: 1) Sequoia represents latency as accurately as Vivaldi in addition to being the first ”coordinate” system for bandwidth; 2) it enables selection of the closest and the most-provisioned (highest bandwidth) server with low error and overhead; and 3) it computes topologically-aware trees, which can be used to organize a networked,system efficiently.