Beginner LevelCloud Computing (AWS/GCP/Azure)
Compare Application Load Balancer (ALB) vs Network Load Balancer (NLB).
❓ Interview Prompt: Compare Layer 7 ALB vs Layer 4 NLB features, performance, protocols, and use cases.
AWS Elastic Load Balancing (ELB) provides two primary modern load balancer options:
1. Application Load Balancer (ALB - Layer 7):
•
OSI Layer: Operates at the Application Layer (Layer 7 - HTTP/HTTPS/HTTP2/gRPC).
•
Routing Capabilities: Advanced path-based routing ('/api' vs '/static'), host-based routing ('app.com' vs 'admin.com'), HTTP header routing, and cookie sticky sessions.
•
TLS Termination: Offloads SSL/TLS encryption certificates via AWS Certificate Manager (ACM).
2. Network Load Balancer (NLB - Layer 4):
•
OSI Layer: Operates at the Transport Layer (Layer 4 - TCP/UDP/TLS).
•
Performance: Capable of handling millions of requests per second with ultra-low sub-millisecond latency.
•
Static IP: Provides dedicated static IP addresses (or Elastic IPs) per Availability Zone. Ideal for non-HTTP protocols, gaming, or financial trading APIs.
Code Implementation Example
typescript
function chooseLoadBalancer(protocol: 'HTTP' | 'TCP', needsUltraLowLatency: boolean) {
if (protocol === 'HTTP' && !needsUltraLowLatency) {
return 'Application Load Balancer (ALB - Layer 7)';
}
return 'Network Load Balancer (NLB - Layer 4)';
}💡Decision helper for ALB vs NLB selection.
🎯 Interview Key Takeaway
ALB handles Layer 7 HTTP/HTTPS path-based routing; NLB handles Layer 4 TCP/UDP for ultra-low latency and static IPs.
#ALB#NLB#Load Balancing#Layer 7#Beginner
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