Application load balencer Vs Network load balencer Vs Gateway load balencer in AWS with real world examples
Published: 2023-08-06 11:26:24

In AWS, load balancers are used to distribute incoming network traffic across multiple resources (such as instances, containers, or IP addresses) to ensure high availability and optimal performance. There are three main types of load balancers in AWS: Application Load Balancer (ALB), Network Load Balancer (NLB), and Gateway Load Balancer (GWLB). Each type serves different purposes and is suitable for different use cases. Let's explore the differences between them with real-world examples:

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/cb70nb0lzkbogw7n17o7.png)

**_Application Load Balancer (ALB):_**
ALB operates at the application layer (Layer 7) of the OSI model and is best suited for routing HTTP/HTTPS traffic. It allows you to make intelligent routing decisions based on URL path, host headers, and HTTP methods. ALB supports content-based routing and can handle more advanced features like path-based routing and host-based routing.

**Real-World Example:** An e-commerce website that offers different services, such as shopping cart, user authentication, and product search, can use an ALB to route traffic to different backend services based on the URL path. For instance, incoming requests to /cart can be directed to a different set of instances than requests to /search.

**_Network Load Balancer (NLB):_**
NLB operates at the transport layer (Layer 4) of the OSI model and is designed to handle TCP, UDP, and TLS traffic. It is used for scenarios where high throughput and low latency are crucial, such as gaming or real-time communication applications. NLB provides a static IP address for the load balancer, making it suitable for applications that require clients to connect to a fixed IP.

**Real-World Example:** A gaming company running a multiplayer online game can use an NLB to distribute incoming traffic from players to game servers. NLB ensures low latency and high throughput, which are essential for delivering a smooth gaming experience.

**_Gateway Load Balancer (GWLB):_**
GWLB is a specialized load balancer that is used to route traffic from virtual appliances (such as firewalls, intrusion detection systems, or WAN optimizers) to your VPC resources. It operates at the network layer (Layer 3) and can work with Network Address Translation (NAT) devices as well.

**Real-World Example:** A company wants to enforce network security policies by routing all outgoing traffic from its VPC through a virtual firewall. The GWLB can be used to direct traffic from instances within the VPC to the virtual firewall instances, ensuring that all outbound traffic is inspected and controlled.

In summary:

ALB is suitable for routing HTTP/HTTPS traffic and provides advanced routing capabilities based on content.
NLB is ideal for high-throughput, low-latency scenarios that involve TCP, UDP, or TLS traffic.
GWLB is used to route traffic to virtual appliances for network security and other purposes.
Choose the type of load balancer that aligns with your specific application requirements and architecture to achieve the desired performance, availability, and functionality.