Anycast
Anycast is a network addressing and routing scheme whereby data is routed to the "nearest" or "best" destination as viewed by the routing topology. On the Internet, anycast is usually implemented by using BGP to simultaneously announce the same destination IP address range from many different places on the Internet. This results in packets addressed to destination addresses in this range being routed to the "nearest" point on the net announcing the given destination IP address.
This is best suited to connectionless protocols based on UDP, such as DNS. As a consequence, Anycast is commonly used to deploy high-capacity, highly resilient DNS systems. Several of the root servers are provided via Anycast.
External Links
- Anycast article on Wikipedia
- RFC3258, Distributing Authoritative Name Servers via Shared Unicast Addresses
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