Abstract: Techniques are described to determine clients residing behind LDNS resolvers. Web beacons instruct clients to retrieve zero-content images at unique hostnames. A request to the hostname is made by a client to an LDNS resolver. The LDNS sends the request to an authoritative server/beacon resolver for the hostname. The beacon resolver records the hostname with the LDNS resolver's IP address and responds with an IP address of a beacon collection server that is forwarded to the client by the LDNS. The client sends a request containing the unique hostname to the beacon collection server. The beacon collection server records the IP address of the client and the hostname. An aggregation server collects data from the beacon resolver and the beacon collection server. Using the hostnames as keys, IP addresses of clients are mapped to IP addresses of LDNS resolvers. Mapped data is exported to load balancing servers to determine routing.

Abstract: 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 also the closest web server to the client.

Abstract: Techniques are described for measuring TCP connection quality between a client and a plurality of data centers. A small amount of code, called a web beacon, is placed onto production web pages. When a client requests the production web page, the web page is served to the client. When the web page code is processed, the web beacon instructs the client to retrieve zero-content images from a plurality of data centers through TCP connections in the background. As each connection is made, a passive monitoring system measures and logs statistics about each TCP connection from the client to the data center. The statistics are aggregated into a database and may be sorted based upon ranges of IP addresses of clients and the connection quality measurements. The data is exported from the database to global load balancers to determine routing from subsequent clients to the plurality of data centers.

Abstract: 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 also the closest web server to the client.

Abstract: 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 also the closest web server to the client.

Abstract: Techniques are described for measuring TCP connection quality between a client and a plurality of data centers. A small amount of code, called a web beacon, is placed onto production web pages. When a client requests the production web page, the web page is served to the client. When the web page code is processed, the web beacon instructs the client to retrieve zero-content images from a plurality of data centers through TCP connections in the background. As each connection is made, a passive monitoring system measures and logs statistics about each TCP connection from the client to the data center. The statistics are aggregated into a database and may be sorted based upon ranges of IP addresses of clients and the connection quality measurements. The data is exported from the database to global load balancers to determine routing from subsequent clients to the plurality of data centers.

Abstract: Techniques are described to determine clients residing behind LDNS resolvers. Web beacons instruct clients to retrieve zero-content images at unique hostnames. A request to the hostname is made by a client to an LDNS resolver. The LDNS sends the request to an authoritative server/beacon resolver for the hostname. The beacon resolver records the hostname with the LDNS resolver's IP address and responds with an IP address of a beacon collection server that is forwarded to the client by the LDNS. The client sends a request containing the unique hostname to the beacon collection server. The beacon collection server records the IP address of the client and the hostname. An aggregation server collects data from the beacon resolver and the beacon collection server. Using the hostnames as keys, IP addresses of clients are mapped to IP addresses of LDNS resolvers. Mapped data is exported to load balancing servers to determine routing.

Abstract: Techniques are described for making the best connection between a client and a server. The best connection is determined based upon the proximity of the client to the server, and the load and availability of the server. Proximity is determined by connection racing in which response times to requests made to various sets of servers are compared. The load is determined by back-end monitoring logic for each set of servers and is indicated in the response sent by the server. The availability of the server is monitored by a virtual IP server located with each set of servers. The virtual IP server selects available servers to respond to the request from the client. When the client receives responses, the client selects a server based on (a) the response times and (b) load information in the responses in order to make the best connection.