Part 2: Cost of Latency Series: Welcome to Geo Distributed Architecture using Route53 LBR

Welcome to Geo Distributed Architecture (Using Route53 LBR)

In this architecture, the web/app infrastructure of the XYZ Airlines is geo distributed across multiple AWS regions (example Singapore, Japan, Europe etc). 

User requests originating all around the world are directed to the nearest AWS region or AWS region with lowest network latency (more precisely). For example, suppose you have Load balancers in the Singapore, Japan and Europe Amazon EC2 region and we have created a latency resource record set in Route 53 for each load balancer. An end user in Dubai enters the name of our domain in their browser, and the Domain Name System routes their request to a Route 53 name server. Route 53 refers to its data on latency between Dubai and the Europe EC2 region and between Dubai and the Singapore EC2 region. If latency is lower between Dubai and the Europe region( most of the times), Route 53 responds to the end user's request with the IP address of your load balancer in the Amazon EC2 data center in Europe EC2 region. If latency is lower between Dubai and the Singapore region, Route 53 responds with the IP address of the load balancer in the Amazon EC2 data center in Singapore. This architecture rapidly cuts down the latency and gives the user a better experience. Also in case one of the regions is facing network problems, the requests can be routed to alternate low latency region achieving High Availability at overall website level. Though this architecture has benefits it comes with various complexities depending upon the use case and technical stack used, we will uncover some of them in this article.

If the XYZ airline follows GEO distributed architecture and has data centers in Singapore, Japan and Europe, let us see what it takes as the roundtrip latency measurements to access their website:

The XYZ airlines website is hosted on multiple AWS region with LBR configured	From Japan (ms)	From Germany(ms)	From Malaysia (ms)	From Rio (ms)
	12	21	30	75

Note: The above measurements are not constant and may keep varying every few seconds.

From the above table we can observe that using the Geo Distributed architecture the HTTP/S and AJAX calls are delivered from the AWS regions with lowest latency (usually nearest region), the round trip latency measurements have significantly dropped and overall performance has increased for the users.

View Full Detailed article at http://harish11g.blogspot.in/2012/09/geo-distributed-route53-lbr-latency.html