Why use Amazon Elastic Load Balancer?

• An ELB is a managed load balancer.
• AWS gurantees that it will be working.
• AWS takes care of upgrades, maintainance, high availablity.
• AWS provides only a few configuration knobs.
• it costs less to setup our own load balancer but it will be a lot more effort on your end (maintainence, integration).

There are 4 kinds of load balancer offered by AWS:

Name	Layer	Remark
Application Load Balancer (ALB)	Layer 7	HTTP/HTTPs only
Network Load Balancer (NLB)	Layer 4	Ultra-High Peformance, allows TCP
Gateway Load Balancer (GLB)	Layer 3	routing on IPs
Classic Load Balancer	Layer 4&7

Application Load Balancer

• HTTP / HTTPs / GRPC protocol
• Layer 7
• Http Routing Features
• Static DNS (URL)

Network Load Balancer

• TCP / UDP protocols
• Layer 4
• Static IP through AWS ElasticIP.

Gateway Load Balancer

• GENEVE Protocol on IP Packets.
• Layer 3
• Route traffic to firewalls that you manage on EC2 instance.
• Good for Intrusion Detection.