AWS Load Balancers

Presenter: Abhishek

Load Balancer: Manages incoming web traffic across multiple servers
OSI Model: 7-layer model of network communication; key to understanding load balancer functionality

Initial setup: Single EC2 instance
Issues: Increased users lead to slowness and downtime
Solution: Deploy multiple EC2 instances with a load balancer in front
- Load balancer distributes requests equally (e.g., round-robin)
- Ensures highly available and responsive application

Application Load Balancer (ALB)
- Operates at Layer 7 (Application Layer)
- Routes traffic based on HTTP/HTTPS details like path, host, and headers
- Suitable for complex routing needs (e.g., different paths on a website)
- Features like SSL offloading
- Pros: Advanced routing capabilities
- Cons: Costly, potential latency
Network Load Balancer (NLB)
- Operates at Layer 4 (Transport Layer)
- Routes TCP/UDP traffic quickly
- Suitable for applications needing low latency (e.g., streaming platforms, game servers)
- Pros: Fast, less costly, supports sticky sessions
- Cons: Limited routing capabilities compared to ALB
Gateway Load Balancer (GWLB)
- Used for virtual appliances like VPNs and firewalls
- Ensures high security and proper traffic handling
- Offers encrypted traffic transmission
- Not suitable to replace with ALB or NLB due to specialized traffic requirements

Layer 7 (Application): Protocols such as HTTP, FTP; determines the type of request
Layer 6 (Presentation): Encoding/Encryption (e.g., SSL/TLS)
Layer 5 (Session): Manages sessions between client and server
Layer 4 (Transport): Splits data into packets (TCP/UDP)
Layer 3 (Network): Packet routing through routers
Layer 2 (Data Link): Manages transmission over local network segments
Layer 1 (Physical): Physical cabling and connections