Network Load Balancer (NLB) operates at Layer for TCP, UDP, and TLS. It provides ultra-low latency and millions of requests per second.
Performance:
- Handles sudden spikes without warmup
- Millions of connections
- Single-digit millisecond latencies
- Preserves source IP by default
Static IPs: NLB provides one static IP per AZ. Useful when clients whitelist specific IPs.
Use NLB when:
- You need extreme performance
- Protocol is not HTTP
- Clients require static IPs
- You need source IP preservation
NLB costs less than ALB for high-volume TCP traffic. Pricing is connection-based.