Oracle Corporation
GLOBAL LOAD BALANCING ACHIEVED BY USING DISTRIBUTED DNS REFLECTION

Abstract:

Round-trip times (RTT) values are estimated between meshed data centers serving an internet domain and a local domain name server (LDNS) associated with the data centers. A method initializes a shared database with proactively estimated RTTs and uses distributed DNS reflection to improve the accuracy of an estimated RTT value and update the shared database. RTTs may be proactively estimated by using pings, queries, or local DNS reflection. In local DNS reflection, a reflector sends a request to a collector in the same data center via the LDNS, and the collector measures the RTT. In distributed DNS reflection, a reflector in a first data center sends a request to a collector in a second data center via the LDNS. The collector calculates the latency, retrieves the (first) RTT between the first data center and the LDNS, and calculates the (second) RTT between the second data center and the LDNS by doubling the difference between the latency and half the first estimated RTT.