Oracle Corporation
Method and apparatus for accurate GLB achieved by using distributed DNS reflection

Abstract:

An example method facilitates Global Traffic Management (GTM) using a combination of passive latency measurements and active latency measurements, including Domain Name System (DNS) server reflection methods, that estimate Round Trip Times (RTTs) between individual geographically distributed data centers (servicing a particular domain) and Local Domain Name Servers (LDNSs) communicating with the data centers. Passive and/or active measurements may initialize a shared database (e.g., accessible by the data centers via a web service). After initialization of the database using static and/or active methods to provide initial estimates of RTTs, different DNS reflection methods then accurately estimate the RTTs and populate the database therewith. The different DNS reflection methods include a first DNS reflection method using co-located reflectors and collectors, and a second distributed DNS reflection method that does not require co-located DNS reflectors and collectors, but instead may employ a hierarchy of reflectors and collectors deployed at different data centers servicing the same domain.