The three tier is a common architecture for web applications. This architecture is designed to be highly scalable by providing the web tier, which is responsible for the incoming requests from the Elastic Load Balancer. They act as a proxy layer, then these requests are propagated to the middleware tier.
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Route 53
DNS requests are solved by Route 53 (1) answering with a CloudFront distribution (2) with origin on S3 (3) for static assets and an ELB for dynamic data (4). The best practice is to offload all static data to S3 buckets by removing servers the responsibility to manage data. This decouples other layers (5) and provides maximum flexibility when resources are created or terminated by Auto Scaling...
