It is unique because multiple physical devices share this IP address in various locations.
Usually, these devices are servers.
This is often described as a one-to-one-of-many transmission.
Consider the following example: Three servers in Italy, Canada, and Mexico share an IP address.
This way, there is little to no downtime, and services remain available.
In contrast, Multicasting sends data to all group members, not just one.
Intermediary devices generally dont even need to support Anycast.
The actual message is unicast to a single IP.
Anycast only affects the virtual routing on the internet, so your home router doesnt need to understand it.
Routing is based on the routing cost to each advertised server.
Only the route with the lowest cost is chosen.
Anycast is particularly well-established in IPv6 protocols, offering reduced access times and easy load distribution for access.
Fun fact:DDoS protection services like Cloudflare often use Anycast to protect their clients.
This minimizes the overall effect on any server, allowing the target and internet to continue normal operations.
This can mean the attempt to shut down a site completely fails.
Even hitting 300Gbps, the attack still couldnt circumvent the Anycast system setup.
Conclusion
Anycast is an addressing scheme where several servers are assigned the same shared IP address.
