Route 53, CloudFront & ELB

DNS routing, CDN, and load balancing.

Getting traffic to your application — and distributing it — relies on the edge and load-balancing services: Route 53 for DNS, CloudFront for content delivery, and Elastic Load Balancing for spreading traffic across instances.

DNS and content delivery

Amazon Route 53 is scalable DNS with health checks and routing policies that do real architecture work: latency-based routing sends users to the lowest-latency Region, failover routing directs traffic to a healthy stack when the primary fails, and weighted or geolocation routing splits traffic deliberately. Amazon CloudFront is the CDN: it caches content at edge locations close to users, cutting latency and offloading your origin, and it can front an S3 bucket (for static sites) or a load balancer (for dynamic apps), adding TLS termination and AWS WAF at the edge. Together they bring your application close to a global audience.

user ──DNS──▶ Route 53 (latency / failover / weighted routing)
      ──HTTPS─▶ CloudFront (edge cache + TLS + WAF)
                  ├─ static assets ──▶ S3 origin
                  └─ dynamic ────────▶ Application Load Balancer
                                         └─ target group (EC2 across AZs)

Load balancing

Elastic Load Balancing distributes incoming traffic across healthy targets in multiple AZs, which is the backbone of a resilient tier. The Application Load Balancer operates at Layer 7 (HTTP/HTTPS) and routes on paths, hostnames, and headers to different target groups — ideal for microservices and web apps. The Network Load Balancer operates at Layer 4 for extreme performance, millions of connections, and static IPs — for TCP/UDP and latency-critical workloads. A load balancer combined with an Auto Scaling group across AZs gives you both high availability (unhealthy targets are bypassed) and elasticity (capacity follows demand), the classic AWS web-tier pattern.