Anycast is a network addressing and routing method where many CDN nodes announce the same IP address, and the internet's routing automatically delivers each viewer's request to the topologically nearest one. It is one of the two main ways CDNs steer traffic to the right edge (the other being DNS-based routing).
Anycast reacts quickly to network conditions and node failures - if a PoP drops out, routing converges to the next nearest - which makes it resilient and simple from the client's view. Its limitation is coarser control compared to DNS or application-layer steering, so large platforms often combine techniques to balance precision, performance, and failover.
