ROUTING VIA ANYCAST

At its most basic, anycast can be defined as communication between a single client and the topologically closest instance of a network service that is represented in multiple places by a common IP address.

IP anycasting allows a single name server IP address to exist in multiple locations at a given time. In this approach, DNS requests are routed between a single source (the client’s DNS recursive name server) and the topologically closest authoritative node. In theory, the client reaches the topologically closest anycast instance, as determined by Internet routing protocol metrics; however, all instances are configured with the same IP address and provide exactly the same service.

BENEFITS TO ANYCAST

• Enables organisations to expand the footprint and capacity available via a given IP service address.
• Reduces latency and enhances performance by optimising for client proximity to authoritative name servers.
• Helps balance, distribute and localise query loads.
• Provides massive scalability via inherent caching processes and a distributed, decentralised resolution database architecture.
• Strengthens resistance to denial of service (DoS) and distributed denial of service (DDoS) attacks by increasing redundancy and distributing resolution activities across more geographically disperse locations.