Routing substrates for overlay networks are an important building block for large distributed applications. Many existing substrates are based on a random identifier space and therefore do not respect node locality when routing data. This can lead to lower performance for locality-sensitive applications, such as web caching, distributed gaming, and resource discovery.
This paper examines the problem of building a locality-aware routing substrate on top of a locality-based coordinate system, where the distance between coordinates approximates network latencies. As a starting point we take the scaled θ-routing proposal for geometric routing in a Euclidean space. We address the practical problems of forming routing tables with imperfect node knowledge and churn and examine query performance on non-Euclidean data sets.