US 10,951,576 B1Granted

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

AssigneeOracle International Corporation

InventorRishi Mutnuru

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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.

Claims20

Dependent claims

A tangible non-transitory processor-readable medium including instructions executable by one or more processors, and when executed operable for:

receiving, at a first reflector of a first data center, a first request to resolve a first domain name to its Internet Protocol (IP) address;
using the first reflector and a first collector at the first data center to selectively communicate with a Local Domain Name Server (LDNS) to estimate a first Round Trip Time (RTT) between the first data center and the LDNS, which issued the first request to the first data center, using a first DNS reflection method, wherein the first DNS reflection method includes:
reflecting the first request to the first collector at the first data center via an adjusted first request sent to the LDNS, wherein the adjusted first request represents an adjusted version of the first request, wherein adjustments to the first request that are included in the adjusted first request include a first time stamp indicating when the first request was received by the first reflector, and wherein the adjustments further include an IP address of the first collector located at the first data center;
computing a first RTT value between the first data center and the LDNS based on a difference between a time at which the first collector receives the adjusted first request and a time indicated by the first time stamp included in the adjusted first request;
and
storing the first RTT value in a database that is accessible to and updatable by the first data center and a second data center;
receiving a second request at the first reflector of the first data center to resolve the first domain to its IP address;
and
employing the first reflector and a second collector at a second data center to selectively communicate with the LDNS to facilitate estimating a second RTT between the second data center and the LDNS using a second DNS reflection method, wherein the second DNS reflection method includes:
using the first reflector to reflect the second request to the second collector at the second data center via the LDNS via an adjusted second request, wherein the adjusted second request represents an adjusted version of the second request, and wherein adjustments to the second request that are included in the adjusted second request include a second time stamp indicating when the second request was received by the first reflector;
receiving, at the second collector, the adjusted second request;
using the adjusted second request;
a time at which the adjusted second request was received by the second collector;
the second time stamp, and the first RTT value to estimate a second RTT value between the second data center and the LDNS;
and
storing the second RTT value in the database.

13 more elements

A method for facilitating Global Load Balancing (GLB) for a network of distributed meshed data centers, the method comprising:

receiving, at a first reflector of a first data center, a first request to resolve a first domain name to its Internet Protocol (IP) address;
using the first reflector and a first collector at the first data center to selectively communicate with a Local Domain Name Server (LDNS) to estimate a first Round Trip Time (RTT) between the first data center and the LDNS, which issued the first request to the first data center, using a first DNS reflection method, wherein the first DNS reflection method includes:
reflecting the first request to the first collector at the first data center via an adjusted first request sent to the LDNS, wherein the adjusted first request represents an adjusted version of the first request, wherein adjustments to the first request that are included in the adjusted first request include a first time stamp indicating when the first request was received by the first reflector, and wherein the adjustments further include an IP address of the first collector located at the first data center;
computing a first RTT value between the first data center and the LDNS based on a difference between a time at which the first collector receives the adjusted first request and a time indicated by the first time stamp included in the adjusted first request;
and
storing the first RTT value in a database that is accessible to and updatable by the first data center and a second data center;
receiving a second request at the first reflector of the first data center to resolve the first domain to its IP address;
and
employing the first reflector and a second collector at a second data center to selectively communicate with the LDNS to facilitate estimating a second RTT between the second data center and the LDNS using a second DNS reflection method, wherein the second DNS reflection method includes:
using the first reflector to reflect the second request to the second collector at the second data center via the LDNS via an adjusted second request, wherein the adjusted second request represents an adjusted version of the second request, and wherein adjustments to the second request that are included in the adjusted second request include a second time stamp indicating when the second request was received by the first reflector;
receiving, at the second collector, the adjusted second request;
using the adjusted second request;
a time at which the adjusted second request was received by the second collector;
the second time stamp, and the first RTT value to estimate a second RTT value between the second data center and the LDNS;
and
storing the second RTT value in the database.

13 more elements

Dependencies are inferred from the claim text.