vacuum Time, light in fiber Round-trip time (RTT) in fiber HN → SG 1,615km 5.3ms 8.8ms 17.6ms HN → Singapore 2,212km 7.4ms 12.3ms 24.6ms HN → Tokyo 3,665km 12.2ms 20.3ms 40.6ms HN → San Francisco 11,752km 39.2ms 65.3ms 130.6ms RTT thực tế giữa HN & SG là ở khoảng 25-30ms.