Senior LevelSystem Design & Architecture
How does Latency-Based DNS Routing and AWS Route 53 Latency Records route users?
❓ Interview Prompt: Explain Latency-Based DNS Routing, AWS Route 53 latency records, global health checks, and multi-region failover.
Latency-Based DNS Routing automatically directs end-user traffic to the cloud region that provides the lowest round-trip network latency:
Mechanics:
1
Cloud providers measure network latency from global user ISP networks to AWS/GCP data center regions continuously.
2
When a user queries DNS for 'api.example.com', Route 53 selects the IP of the region with the lowest historical latency for that user's ISP!
3
If a region fails health checks, DNS routes traffic to the second-lowest latency region automatically.
Code Implementation Example
json
{
"dnsRecord": "api.example.com",
"routingPolicy": "Latency-Based Routing",
"regions": [
{ "region": "us-east-1", "latencyMs": 12, "status": "HEALTHY" },
{ "region": "eu-central-1", "latencyMs": 110, "status": "HEALTHY" }
],
"selectedTarget": "us-east-1 (Lowest Latency Target)"
}💡Latency-based DNS routing target evaluation payload.
🎯 Interview Key Takeaway
Deploy Latency-Based DNS routing to direct global user traffic to the fastest cloud region automatically.
#System Design#DNS Routing#Route 53#Multi-Region#Senior
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