AWS Certified Advanced Networking Specialty Practice Exam

What feature of the Elastic Load Balancer (ELB) is utilized in the described application architecture?

1. Sticky sessions

2. Round-robin configuration

3. Session affinity

4. URL-based routing

The correct answer is: Round-robin configuration

In the context of Elastic Load Balancers (ELB), the feature that is recognized in application architectures often centers on how traffic is managed and distributed among various instances. The round-robin configuration allows the load balancer to distribute incoming requests evenly across multiple targets, ensuring an effective load distribution. This method is significant in keeping workloads balanced, particularly in situations where each request is independent of others. By using round-robin, all instances behind the load balancer receive an equal share of traffic over time, thus optimizing resource utilization and enhancing overall application performance. In contrast, sticky sessions or session affinity refer to keeping a user's requests directed to the same instance, which is useful for maintaining state but does not focus on equal load distribution. URL-based routing, while beneficial for directing specific requests to certain backend services based on URL paths, does not inherently provide a mechanism for ensuring balanced traffic across multiple instances. Thus, the round-robin configuration is a foundational feature for achieving load balancing in applications, aligning perfectly with the need for an efficient response to varying levels of incoming traffic.