Persistent Last-mile Congestion: Not so Uncommon

ABSTRACTLast-mile is the centerpiece of broadband connectivity, as poor last-mile performance generally translates to poor quality of experience. In this work we investigate last-mile latency using traceroute data from RIPE Atlas probes located in 646 ASes and focus on recurrent performance degradation. We find that in normal times probes in only 10% ASes experience persistent last-mile congestion but we recorded 55% more congested ASes during the COVID-19 outbreak. Persistent last-mile congestion is not uncommon, it is usually seen in large eyeball networks and may span years. With the help of CDN access log data, we dissect results for major ISPs in Japan, the most severely affected country in our study, and ascertain bottlenecks in the shared legacy infrastructure.