Mapless global traffic load balancing via anycast

摘要

Techniques are described for directing connections between clients and the closest web server. Authoritative DNS resolvers of a network are placed at edges of the network. Using anycast, the authoritative DNS resolvers advertise routes of their destination netblock to the Internet. A request from a client to connect to the network is routed, based upon BGP tables, to the closest particular authoritative DNS resolver. Once the request is received, a response is sent to the client with the IP address of the closest web server. The closest web server is determined through in-network health check measurements, with the authoritative DNS resolvers dynamically selecting IP addresses closest to themselves. Routing protocols that directed the packet to the closest authoritative DNS resolver also dictate the route of subsequent traffic to the network. Thus, the closest web server selected by the authoritative DNS resolver is the closest web server to the client.