Investigating Location-aware Advertisements in Anycast IP Networks

Kastanakis, Savvas and Giotsas, Vasileios and Livadariu, Ioana and Suri, Neeraj (2024) Investigating Location-aware Advertisements in Anycast IP Networks. In: ANRW '24: Proceedings of the 2024 Applied Networking Research Workshop :. ACM, New York, pp. 15-22. ISBN 9798400707230

Abstract

Anycast routing offers transparent service replication by distributing traffic across multiple Points of Presence (PoP). By advertising the same IP prefix from each PoP via BGP, traffic is routed to the nearest server, minimizing user latency. Despite its perceived benefits, prior research suggests IP anycast often falls short, with clients routed to distant replicas, increasing latency. Selective announcements made by anycast ASes contribute to this inefficiency, serving as a traffic engineering strategy to control incoming traffic flows. In this work, we aim to shed light on the prevalence and rationale behind selective announcements in anycast networks. Through empirical evidence, we identify their significant adoption, primarily driven by the geolocation-agnostic BGP best path selection process. In particular, we observe that 84.06% of anycast ASes announce at least one of their anycast prefixes to a specific subset of their neighbors, whereas 80% of these selective announcers announce 100% of their prefixes selectively. This research represents an initial step towards comprehending the effects of selective and location-based routing policies in anycast IP networks.