A view from the edge: A stub-AS perspective of traffic localization and its implications

Serving user requests from near-by caches or servers has been a powerful technique for localizing Internet traffic with the intent of providing lower delay and higher throughput to end users while also lowering the cost for network operators. This basic concept has led to the deployment of different types of infrastructures of varying degrees of complexity that large CDNs, ISPs, and content providers operate to localize their user traffic. Prior measurement studies in this area have focused mainly on revealing these deployed infrastructures, reverse-engineering the techniques used by these companies to map end users to close-by caches or servers, or evaluating the performance benefits that “typical” end users experience from well-localized traffic. To our knowledge, there has been no empirical study that assesses the nature and implications of traffic localization as experienced by end users at an actual stub-AS. This paper reports on such a study for the stub-AS UOnet (AS3582), a Research & Education network operated by the University of Oregon. Based on a complete flow-level view of the delivered traffic from the Internet to UOnet, we characterize the stub-AS's traffic footprint (i.e. a detailed assessment of the locality of the delivered traffic by all major content providers), examine how effective individual content providers utilize their built-out infrastructures for localizing their delivered traffic to UOnet, and investigate the impact of traffic localization on perceived throughput by end users served by UOnet. Our empirical findings offer valuable insights into important practical aspects of content delivery to real-world stub-ASes such as UOnet.