Too Remote to Be Local Latency Inflation in Anycast due to Remote Peering

Remote peering (RP) enables networks to reach Internet Exchange Points (IXPs) without physical presence in the same datacenter/location, offering cost-effective interconnection. However, in the context of anycast, where routing efficiency relies on the assumption that traffic is routed to the geographically nearest instance, RP can undermine this principle by introducing hidden performance costs and inflating paths. % latencies. This paper presents a hybrid methodology, combining data-plane measurements with control-plane insights, to detect and geolocate RP links at scale using IP-level geolocation, AS-level mapping, and IXP facility data. Using 3 million traceroutes targeting 13,735 anycast /24-prefixes, we quantify the impact of RP on anycast routing. Our analysis shows that whilst RP is widespread, it often connects ASes geographically close to the IXP facility. However, for cases where it is ``remote'' we find it frequently results in long detours, elevated latency, and sub-optimal anycast site selection. Finally, we identify key ASes and IXP regions that play a central role in driving RP-related detours and locality violations in anycast routing. Our findings demonstrate at Internet scale that RP undermines anycast locality by increasing the likelihood of detours and inflated paths, underscoring the need for improved visibility into interconnection practices that impact latency-sensitive services.