Anycast
One IP address announced from many locations, so the network routes each user to the nearest instance automatically.
Anycast is a network addressing method where the same IP address is announced from multiple locations, and the internet’s routing (BGP) delivers each user’s packets to the topologically nearest one. It is how CDNs and global DNS route users to a close server without any application logic.
Worked example: a DNS resolver or CDN edge answers on one anycast IP worldwide; a user in Tokyo and one in Paris hit the same address but reach different nearby servers, chosen by the network. Gotcha: anycast is great for stateless request/response traffic (DNS, CDN, DDoS absorption) but tricky for long-lived stateful connections — a routing change mid-connection can flip you to a different server that has no idea about your session — so it is not a drop-in for stateful services.