Microsoft Certified: Azure Fundamentals (AZ-900) Practice Exam

Which service can improve application availability by distributing traffic among multiple instances?

1. Azure Traffic Manager

2. Azure Load Balancer

3. Azure CDN

4. Azure Application Gateway

The correct answer is: Azure Load Balancer

Azure Load Balancer is a service specifically designed to improve application availability by distributing incoming network traffic across multiple instances of a service. When an application is deployed in multiple instances, the Load Balancer ensures that workload is efficiently distributed, which helps in achieving higher availability and better resource utilization. This service operates at the transport layer (Layer 4) of the OSI model, allowing it to manage both TCP and UDP traffic. By leveraging Azure Load Balancer, applications can scale out, facilitating a balanced load across various instances. This means that if one instance becomes unavailable or experiences high latency, the Load Balancer can redirect traffic to other healthy instances, thereby maintaining service continuity and reliability for users. In contrast, Azure Traffic Manager focuses on directing user traffic based on performance or geographic location but does not manage the distribution of network traffic within a single data center. Azure CDN (Content Delivery Network) is designed to deliver content with high availability and performance but does not directly influence application instance throughput. Azure Application Gateway provides application-level routing and can include features like Web Application Firewall capabilities, but it primarily operates at a higher layer and is not the primary tool for basic load balancing across instances.