The first load balancer type is actually one that is no longer with us. It came out in 2009 and operates on layer 4 and 7 of the OSI model. It is the simplest of the load balancers and simply balances traffic to EC2 instances across multiple AZ evenly, unless you opt for crozz-zone load balancing. If you have two AZ and you are not utilizing cross-zone it doesn’t matter if you have 20 instances on one AZ and 2 on the other, they will both received half of the load. With cross-zone this is not as bad as it disregards the AZ and simply distributes among available instances. CLB is fine on paper but has been deprecated due to the much more diverse and powerful options that future load balancers provide.