What is Anycast?
Anycast is a network addressing and routing method where the same IP address is announced from multiple locations around the world, allowing incoming requests to be automatically directed to the nearest or healthiest server.
How Does Anycast Work?
In traditional unicast routing, each IP address corresponds to a single destination. With anycast, the same IP address is assigned to multiple servers in different data centers. When a user sends a request to an anycast address, the network's Border Gateway Protocol (BGP) routing automatically directs the traffic to the topologically closest server, reducing latency and improving response times.
Anycast is widely used by CDN providers and DNS services to deliver content from the location nearest to each user. It also provides built-in redundancy: if one server goes offline, traffic is automatically rerouted to the next-closest node without any configuration changes. This makes anycast an essential technique for building globally distributed, highly available infrastructure.