Multiple hosts (routers or servers) are configured with the same IP address. Each of these hosts advertises this IP into the routing protocol (like BGP). The routing infrastructure (usually BGP) selects the "closest" instance based on the shortest AS path or lowest metric. Traffic destined to that IP is automatically routed to the nearest host from the user’s perspective. 🔄 If one Anycast node goes down, routing protocols simply redirect traffic to the next-best node — providing built-in redundancy and high availability.