Disjoint-Path Selection in Internet: What traceroutes tell us?
  Routing policies used in the Internet can be restrictive, limiting communication between source-destination pairs to one path, when often better alternatives exist. To avoid route flapping, recovery mechanisms may be dampened, making adaptation slow. Unstructured overlays have been proposed to mitigate the issues of path and performance failures in the Internet by routing through an indirect-path via overlay peer(s). Choosing alternate-paths in overlay networks is a challenging issue. Ensuring both availability and performance guarantees on alternate paths requires aggressive monitoring of all overlay paths using active probing; this limits scalability. An alternate technique to select an overlay-path is to bias its selection based on physical disjointness criteria to bypass the failure on the primary-path. Recently, several techniques have emerged which can optimize the selection of a disjoint-path without incurring the high costs associated with probing paths. In this paper, we show that using only commodity approaches, i.e. running infrequent traceroutes between overlay hosts, a lot of information can be revealed about the underlying physical path diversity in the overlay network which can be used to make informed-guesses for alternate-path selection. We test our approach using datasets between real-world hosts in AMP and RIPE networks. 
Sameer Qazi and Tim Moors
cs.NI