ALB vs NLB: The ultimate guide to choosing the best option for your needs

Choosing the right load balancer is crucial when it comes to optimizing the performance and availability of your applications and workloads. There are several options to choose from, but two of the most popular choices are Amazon Web Services (AWS) Application Load Balancer (ALB), and Network Load Balancer (NLB). Each load balancer type has unique features and capabilities, so choosing the right one for your workload is important. In this article, we’ll compare ALB and NLB to help you make an informed decision.

Network Load Balancer (NLB)

Network Load Balancer is a layer 4 load balancer. It load balances incoming connections. When a client opens a connection to the load balancer, it opens a connection to a backend target and forwards all packets from the client to the target.

Application Load Balancer (ALB)

Application Load Balancer is a layer 7 load balancer. It loads and balances HTTP requests. When a client opens a connection to the load balancer, ALB reads and identifies HTTP requests and distributes the HTTP requests across backend targets according to your rules.

Now, let’s take a closer look at the key features and capabilities of each load balancer:

ALB Features

Application Load Balancer (ALB) Content-based routing: As mentioned above, one of the key features of ALB is the ability to route traffic based on the content of the request. This means that you can use ALB to route traffic to different target groups based on the path, host header, or other request attributes.

Protocol support : ALB supports a wide range of protocols, including HTTP, HTTPS, TCP, and SSL. This makes it a good choice for applications that use a variety of protocols.

Health checks : ALB includes built-in health checks that allow it to automatically route traffic away from unhealthy targets. You can customize the health check parameters to fit your specific needs.

Container support: ALB is fully compatible with containerized applications and can route traffic to Amazon Elastic Container Service (ECS) tasks and Amazon Elastic Kubernetes Service (EKS) pods.

SSL offloading: ALB can offload the SSL termination process from your targets, which can help to improve the performance of your application.

NLB Features

Network Load Balancer (NLB) Performance: NLB is designed for high performance and can handle millions of requests per second. It uses a connection-based routing algorithm that ensures that traffic is evenly distributed across targets.

Protocol support: NLB supports TCP, TLS, and UDP protocols. It is particularly well-suited for applications that require low latency and high throughputs, such as gaming and media streaming.

Health checks: NLB includes built-in health checks that allow it to automatically route traffic away from unhealthy targets. You can customize the health check parameters to fit your specific needs.

Container support: NLB is fully compatible with containerized applications and can route traffic to Amazon ECS tasks and Amazon EKS pods.

Cross-zone load balancing: NLB automatically distributes incoming traffic evenly across all available targets in all enabled availability zones. This helps to ensure that your application remains available even if an entire availability zone goes offline.

Now that we’ve reviewed the key features and capabilities of each load balancer, let’s consider some factors to help you choose the right one for your needs:

Considerations for Choosing the Right Load Balancer Application type: As mentioned earlier, ALB is better suited for applications that require more complex routing, while NLB is better suited for applications that require simple, high-performance routing. ALB supports HTTP, HTTPS, TCP, and SSL, while NLB supports TCP, TLS, and UDP. Both ALB and NLB are available on a pay-per-use basis, but the pricing may vary depending on the specific features and usage patterns of your application.

In summary, ALB and NLB are both excellent load-balancing solutions, but they are designed for different types of applications and have different capabilities. By considering the specific needs of your application, you can choose the one that is best suited for your needs.

I hope this helps you make a better decision for your next load balancing on AWS.

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