Even light travels only about 200,000 km per second in optical fiber. A distant server is slow no matter how good it is.
Why The server is far away (an overseas server, another continent) → Effect Round-trip time grows with distance (at least 10 ms per 1,000 km) → On screen Constant input lag on every action and a disadvantage in hit registration
Primary owner Infra team (Server infrastructure) · Also Infra team (Network infrastructure), Game team (Server development)
Game team action items
Mitigate only (code can’t change physics), offer region selection so players pick a nearby server, use lag compensation (rewind) to reduce the hit-registration disadvantage.
Infra team action items
Servers/OS: put regional servers where most players are. Network: put edge locations (PoPs) close to players, choose links and routes with fewer detours.
Ballpark numbers
Seoul–Tokyo about 30 ms, Seoul–Singapore about 75 ms, Seoul–US West Coast about 140 ms, Seoul–Europe about 230–270 ms (round trip, over real routes). Few major cables run along the direct line to Europe, so traffic goes around through Southeast Asia and Suez or through the US, and latency is much higher than the distance alone suggests.
On the graph
Always high · RTT (by country/region)
Where to look
Tag client IPs with a country and look at the RTT distribution per country. Run ping and traceroute to the server from a cloud-region VM in that area or from RIPE Atlas probes (selected by country or ASN)
Confirmed if
RTT from distant countries is always high regardless of time of day, and close to both the minimum delay computed from distance (10 ms round trip per 1,000 km) and public latency statistics
Ruled out if
Far above what distance explains: points to “Detour routing.” Rises only in the evening: “Peak-hour congestion at peering links”
ITU-T G.114: One-way transmission timeITU Planning value for optical fiber propagation delay: 5 µs/km (about 200,000 km per second, 10 ms round trip per 1,000 km)
Azure network round-trip latency statisticsMicrosoft Azure Measured median round-trip times from Seoul (Korea Central): Tokyo 30 ms, Singapore 68 ms, US West 124–136 ms, Europe 234–244 ms
Probe Selection (RIPE Atlas REST API)RIPE NCC Select RIPE Atlas probes by country, region, ASN, or address prefix and run ping and traceroute from them