AWS Gateway Load Balancer (GWLB) Overview

• Purpose: GWLB is used to deploy, scale, and manage fleets of third-party network virtual appliances in AWS.
• Use Cases:
  • Traffic inspection through firewalls.
  • Intrusion Detection and Prevention Systems (IDPS).
  • Deep Packet Inspection (DPI).
  • Network-level payload modification.

How GWLB Works

• Traffic Flow:
  • User traffic is directed to the GWLB before reaching the application.
  • GWLB distributes traffic across a target group of virtual appliances.
  • Appliances analyze and either pass or drop the traffic.
  • Accepted traffic is forwarded to the application.
• Integration:
  • Route tables in the VPC are updated to direct traffic through the GWLB.
  • The application is unaware of the GWLB; the process is transparent.

Key Features

• Operates at Layer 3: GWLB functions at the network layer for IP packets.
• Dual Functionality:
  • Acts as a transparent network gateway.
  • Serves as a load balancer by distributing traffic across virtual appliances.

Target Groups for GWLB

• EC2 Instances: Registered by instance ID.
• IP Addresses: Must be private IPs, can be from your own data center.

Exam Tips

• GENEVE Protocol: If you see GENEVE protocol on port 6081, it's related to GWLB.
• Diagram Understanding: Familiarity with the GWLB diagram is crucial for conceptual understanding.

Conclusion

• GWLB is a powerful tool for network traffic analysis and management.
• Understanding the flow diagram is essential to grasp the concept of GWLB.
• No deep dive questions are expected, just a high-level understanding.