Briefing Amazon Knowledge

Which of the following features ensures even distributi…

Which of the following features ensures even distribution of traffic to Amazon EC2 instances in multiple
Availability Zones registered with a load balancer?

A.
Elastic Load Balancing request routing

B.
An Amazon Route 53 weighted routing policy

C.
Elastic Load Balancing cross-zone load balancing

D.
An Amazon Route 53 latency routing policy

Explanation:
Cross-zone load balancing is always enabled for an Application Load Balancer and is disabled by default for a
Classic Load Balancer. If cross-zone load balancing is enabled, the load balancer distributes traffic evenly
across all registered instances in all enabled Availability Zones. If cross-zone load balancing is disabled, the
load balancer distributes traffic evenly across all enabled Availability Zones. For example, suppose that you
have 10 instances in Availability Zone us-west-2a and 2 instances in us-west-2b. If cross-zone load balancing is
disabled, the requests are distributed evenly between us-west-2a and us-west-2b. As a result, the 2 instances
in us-west-2b serve the same amount of traffic as the 10 instances in us-west-2a. However, if cross-zone load
balancing is enabled, the load balancer distributes incoming requests evenly across all 12 instances.
http://docs.aws.amazon.com/elasticloadbalancing/latest/userguide/how-elastic-load-balancing-works.html