Measurement Informed Route Selection

Abstract

Popular Internet applications exhibit subtle dependencies on data path characteristics [3,5]. On the other hand, various studies [2,1] have shown that nondefault Internet paths can have dramatically different quality characteristics compared to default paths. Unfortunately, the existing Internet routing infrastructure is not able to benefit from these observations. However, recently proposed routing architectures [4] open up the possibility to ease these constraints by allowing route selection to be more dynamic and to be informed by information outside the routing protocol. Motivated by these observations, in the work presented here, we explore the possibility of informing route selection based on measured path properties. Specifically, we observe that from their vantage points in the Internet topology, Tier-1 and other large ISPs typically have multiple possible routes that can be used to reach the majority of destination prefixes on the Internet. By monitoring routing information we track the availability of alternative paths available from a Tier-1 ISP. At the same time we perform detailed measurements of loss and delay to a large number of Internet destinations and characterize various properties of these alternate paths to determine: (i) Whether there are significant differences in the properties of these different paths that would warrant its consideration as part of the route selection process. (ii) The stability of these properties over various timescales which would impact how they can be utilized and dictate the requirements of a measurement infrastructure that can provide such information. We believe this is the first such study involving a single Tier-1 ISP.