Traffic Distribution on AWS: A Comparison of ALB vs NLB
In simpler terms:
- ALB works on Layer 7 (Application Layer)
- NLB works on Layer 4 (Transport Layer)
But in order to understand what exactly is their purpose we need to deep dive into the the networking side of application deployment.
AWS Application Load Balancer
AWS ALB, or Amazon Web Services Application Load Balancer, is a load balancing service for applications that routes traffic to multiple targets, such as EC2 instances, containers, and IP addresses, based on the specific rules that you define. AWS ALB automatically scales to handle incoming traffic and can handle traffic spikes without any manual intervention.
Here’s a fun example to help explain how it works:
Imagine you’re hosting a party at your house and you have a limited number of tables and chairs. As more and more guests arrive, you start to run out of space for them to sit. This is where an ALB comes in!
The ALB acts like a bouncer at your party, directing guests to open tables and chairs as they arrive. If one table gets too crowded, the ALB will redirect some of the guests to other tables to evenly distribute the load.
This way, you can accommodate a large number of guests without any one table becoming overcrowded. Similarly, an ALB can distribute incoming traffic to multiple targets, ensuring that your application can handle a high volume of requests without overloading any one server.
AWS Network Load Balancer
AWS NLB, or Amazon Web Services Network Load Balancer, is a load balancing service for applications that routes traffic to multiple targets, such as EC2 instances and containers, based on the protocol and port that you specify. AWS NLB automatically scales to handle incoming traffic and can handle traffic spikes without any manual intervention.
Here’s a fun example to help explain how it works:
Imagine you’re running a lemonade stand on a busy street corner. As more and more customers arrive, you start to run out of cups to serve them. This is where an NLB comes in!
The NLB acts like a traffic cop at your lemonade stand, directing customers to available cups as they arrive. If one cup gets too full, the NLB will redirect some of the customers to other cups to evenly distribute the load.
This way, you can accommodate a large number of customers without any one cup becoming too full. Similarly, an NLB can distribute incoming traffic to multiple targets, ensuring that your application can handle a high volume of requests without overloading any one server.
ALB vs NLB (How to choose?)
When choosing between an Application Load Balancer (ALB) and a Network Load Balancer (NLB), there are a few key differences to consider.
First, ALBs are best suited for load balancing HTTP and HTTPS traffic, while NLBs are best suited for load balancing TCP traffic. ALBs also support more advanced features, such as host- and path-based routing, whereas NLBs are more focused on raw performance and high availability.
Another key difference between the two is the way they handle incoming requests. ALBs can inspect the content of the request and route it based on the request’s content, whereas NLBs route traffic based on the network connection and protocol.
In general, ALBs are a good choice for applications that require advanced routing capabilities and support for HTTP and HTTPS traffic, while NLBs are a good choice for applications that require high performance and availability for TCP traffic. Ultimately, the right choice will depend on the specific needs of your application.
Implementing ALB and NLB
To implement an Application Load Balancer (ALB) or a Network Load Balancer (NLB), you will need to complete the following steps:
- Sign up for an AWS account and create a load balancer using the AWS Management Console.
- Configure the load balancer with the appropriate settings, such as the load balancer type (ALB or NLB), the listeners (the ports that the load balancer will listen on), and the security settings.
- Add one or more targets (such as EC2 instances) to the load balancer. This is where incoming traffic will be directed.
- Configure the load balancer’s routing rules to specify how incoming traffic should be routed to the targets. For example, you can configure the load balancer to route traffic based on the URL path or the hostname.
- Test the load balancer to ensure that it is routing traffic as expected.
Once the load balancer is set up and configured, it will automatically distribute incoming traffic across the targets, ensuring that your application can handle a high volume of requests without overloading any one server.
Overall, both AWS ALB and AWS NLB are load balancing services offered by Amazon Web Services that can help distribute incoming traffic to multiple targets, improve the availability and performance of your applications, and automatically scale to handle traffic spikes without any manual intervention.