What is difference between ALB and NLB in AWS?

Select Between (CLB)ELB vs ALB vs NLB

We should begin by comprehending what ELB(Elastic Load Balancer or with new name Classic Load Balancer) is: This service works with both EC2 instances and containers. AWS’s managed load distribution service is called ELB. You may distribute network traffic this way to make applications more scalable. With integrated certificate management, user authentication, and SSL/TLS decryption, you can guarantee the security of your apps.

How it works?[.]

Applications can be delivered with automatic scalability and high availability. You can identify problems and uphold SLA compliance by continuously monitoring the health and performance of your apps. Automatically distributing incoming application traffic between several targets and virtual devices in one or more Availability Zones(AZs) is Elastic Load Balancing (ELB). Okay, now important part is coming:

In 2016, AWS released a new version of Elastic Load Balancing. They are called as: Application Load Balancer (ALB) and Network Load Balancer (NLB). They both use a similar architecture and concepts.

All AWS load blancers, obviously, split up incoming requests across a number of targets, which may be either EC2 instances or Docker containers. They all utilize health inspections to look for hazardous occurrences. They are all quite flexible and widely available. Then what is the difference in between them?

I will try to be as brief as possible…

Network Load Balancer

As you can understand from it”s name, this type is only for the network levels. It neither see nor care anything regarding the application layer, such as cookies, headers, etc. It is context-less and see only the network-layer information contained within the packets it is directing this way and that. The “balancing” job is done here is done only with IP addresses, port numbers, and other network variables.

Application Load Balancer

This service considers a number of factors, including the network and the application. Based on this information, it can route its traffic. It is aware of context and can quickly guide requests based on a single variable or a group of variables.

Key Differences

While the Application Load Balancer(ALB) looks at the HTTP request header to determine where to route the request, the Network Load Balancer(NLB) simply forwards requests. Also Application Load Balancer can guarantee application availability, however Network Load Balancer cannot.