Key points

• ALB provides Layer 7 HTTP/HTTPS host/path routing; NLB provides Layer 4 TCP/UDP/TLS performance and static IP characteristics; Gateway Load Balancer inserts virtual appliances.
• Load balancers distribute traffic and health-check targets but do not create target capacity.
• Multi-AZ target placement, cross-zone behavior, security groups where supported, and health checks affect availability, paths, and cost.

Best-known use cases

• Distribute web traffic across an elastic application tier.
• Balance transport traffic or transparently insert network appliances.

What candidates often confuse it with

• ALB, NLB, and Gateway Load Balancer solve Layer 7, Layer 4, and appliance insertion respectively.
• ELB balances regional targets; Route 53 or Global Accelerator can steer among regional endpoints.

Key takeaway

Choose the ELB family from protocol and target requirements, not from generic performance language.

Related services

• Amazon EC2 Auto Scaling
• Amazon Route 53
• AWS Global Accelerator

Relevant exam tasks

• D2.1
• D2.2
• D3.4
• D4.2

Learn more

• Elastic Load Balancing (ELB)