What Is Anycast Routing?

With standard unicast routing, one IP address belongs to one server. Anycast changes that: the same IP address is assigned to multiple servers in different geographic locations. The internet automatically routes each user to the nearest server advertising that IP.

How the routing happens

Each anycast node announces the same IP prefix via BGP. BGP's path selection algorithm, which considers factors like hop count and network policy, naturally favors the topologically closest announcement. Users don't configure anything; routing happens transparently at the network level.

Why it matters

• Lower latency: users reach the nearest node automatically, with no DNS tricks needed.
• DDoS resilience: attack traffic is spread across all nodes advertising the prefix, rather than concentrating on one location.
• High availability: if one node goes down, BGP withdraws its announcement and traffic routes to the next nearest node.