Load Balancer Connectivity Patterns Part 2: External

Hiya! Bit the Chipmunk here — your friendly AWS study buddy! Today we’re heading out to the edge — exploring how external load balancers connect users to your applications from the internet and beyond.

These are the patterns that make your apps available, scalable, and secure when real users are hitting your endpoints. Let’s dive in! 🌊

🌍 1. Internet-Facing Load Balancing (Public Entry Point)

This is the most common setup: Internet users connect to an Application Load Balancer (ALB) or Network Load Balancer (NLB) placed in public subnets. Those load balancers then route to private targets — your EC2 instances, containers, or IPs inside private subnets.

💡 Bit’s Tip: For questions mentioning “internet-facing endpoint but private backends,” your best answer is public ALB or NLB with private targets. The load balancer provides the security boundary — it’s public on the front, private behind!

🌎 2. Multi-Region Public Entry (Global High Availability)

When users are worldwide, AWS lets you distribute traffic across Regions for latency-based performance and resiliency. You’ll do this with Route 53 and regional load balancers.

💡 Bit’s Tip: Route 53 routing policies (like latency, weighted, or failover) control which Region’s load balancer receives user traffic. If the question says “must route users to the nearest AWS Region” or “must fail over between Regions,” Route 53 + multiple ALBs/NLBs is your friend.

🚀 3. Edge-Optimized and Accelerated Patterns

For global performance, AWS provides services that bring your load balancers closer to your users — either by caching or accelerating network paths.

💡 Bit’s Tip:

• CloudFront is perfect for web content and APIs — it terminates TLS, caches responses, and integrates with ALBs.
• Global Accelerator is protocol-agnostic — it uses AWS’s global network to optimize TCP/UDP paths directly to your load balancer. If the question says “minimize latency for global users” → look for one of these edge solutions.

🧭 4. Centralized Ingress and Egress

When multiple VPCs (or even accounts) need to enter or leave the AWS network through a single inspection point, AWS gives you the Gateway Load Balancer (GWLB). Think of it as a traffic checkpoint — packets come in, get inspected by security appliances (firewalls, IDS/IPS), and then continue on their journey. This is very different from how ALB/NLB work. ALB/NLB forward traffic to its destination; GWLB forwards traffic to an intermediary service before sending it on its way.

🧩 How It Works

• A GWLB is deployed in a dedicated “inspection” or “security” VPC.
• Network appliances (like firewalls or intrusion detection systems) run behind the GWLB.
• Gateway Load Balancer Endpoints (GWLBE) live in the ingress/egress VPC — the one handling internet connectivity or cross-network routing.
• Traffic from application VPCs reaches the inspection layer via Transit Gateway or VPC peering before being directed through the GWLBE → GWLB → appliance path.

The GWLB preserves flow symmetry — every packet in a session follows the same path through the same appliance.

💡 Bit’s Tip:

If you see a question saying “traffic from multiple VPCs or accounts must be inspected before reaching the internet,” your answer is Gateway Load Balancer. If the question says “must route traffic to a shared firewall VPC without exposing the appliances,” again — GWLB is the right choice.

But! If Gateway Load Balancer is not an option, look for AWS Network Firewall — it's an AWS native network firewall that can be used instead of GWLB + third-party newtork appliance.

🧠 Exam Recap: Spot the Connectivity Clues

🐿️ Bit’s Closing Thought

External load balancers are your front doors to AWS applications — and AWS gives you a whole toolbox for controlling where, how, and who can walk through that door.

Choose the right pattern based on who’s connecting, from where, and how public your entry point needs to be.