TCP Traffic Flow

Note: Users communicate with NLB via TCP, but NLB can forward to targets using different protocols.

Layer 4 Load Balancer - TCP/UDP Traffic Handler

Network Load Balancer operates at Layer 4 (Transport Layer), handling TCP and UDP traffic with ultra-high performance and low latency.

Key Features

Performance

• Millions of requests per second
• Ultra-low latency (~100 microseconds)
• Fastest AWS Load Balancer option

Network Characteristics

• Operates at Layer 4 (TCP/UDP)
• Does NOT understand HTTP/HTTPS (Layer 7)
• Works at connection level

Static IP Support

• One static IP per Availability Zone
• Supports Elastic IP assignment
• Ideal for IP whitelisting scenarios

Example:

NLB in us-east-1a → Static IP: 13.235.45.67
NLB in us-east-1b → Static IP: 52.123.78.90
NLB in us-east-1c → Static IP: 34.201.12.34