Examples: Apache, Nginx. Generally a load balancer consists of several parts: listener, listener rule and target groups.

Modes of operation: In-line or DSR

• In-line means that the load balancer will handle all incoming and outgoing connection between the client and the http server
• DSR (direct server return) means that the incoming connections may come through the load balancer, but outgoing connections will be between the web server and the client.

Threads or forks

• Threads consume less resources but are more complex.
• Forks are the default.

AWS AWS offers three types of load balancers:

• Application Load Balancer (ALB). Best suited for load balancing of HTTP and HTTPS traffic. Operates at the application layer (Layer 7) of the Open Systems Interconnection (OSI) model.
• Network Load Balancer (NLB). Best suited for load balancing of TCP, UDP, and TLS traffic. Can scale up and down in response to load faster than the ALB (the NLB is designed to scale to tens of millions of requests per second). Operates at the transport layer (Layer 4) of the OSI model.
• Classic Load Balancer (CLB). This is the "legacy" load balancer that predates both the ALB and NLB. It can handle HTTP, HTTPS, TCP, and TLS traffic but with far fewer features than either the ALB or NLB. Operates at both the application layer (L7) and transport layer (L4) of the OSI model.