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Wakeup Flower
Wakeup Flower

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Why use Global Accelerator over LoadBalancer

#aws

1. Global Accelerator

  • What it is: A networking service that uses the AWS global network to improve availability and performance of your apps (any TCP/UDP traffic).

  • How it works:

    • Provides two static Anycast IPs.
    • Routes users to the nearest AWS edge location.
    • From there, traffic enters AWS’s private backbone to your endpoints (ALB, NLB, EC2, or Global Accelerator endpoints).

  • Main benefits:

    • Improves latency for dynamic, non-cacheable traffic (e.g., gaming servers, APIs, financial apps).
    • Automatic failover across AWS Regions for high availability.
    • Works at the transport/network layer, not the content layer.

2. CloudFront

  • What it is: A content delivery network (CDN).

  • How it works:

    • Caches static and dynamic HTTP(S) content at edge locations.
    • Optimizes web delivery (HTTP/2, TLS termination, connection reuse).

  • Main benefits:

    • Great for static content caching (images, CSS, JS, media).
    • Can also optimize dynamic web content, but only for HTTP(S) applications.
    • Works at the application/content layer.

3. When to use which

Use case Use CloudFront? Use Global Accelerator?
Static content (images, CSS, JS) ✅ Best choice ❌ Not for S3/static
Dynamic web apps (HTTP APIs) ✅ Works well ✅ Works (faster routing)
Gaming (TCP/UDP, not HTTP) ❌ Doesn’t apply ✅ Best choice
Multi-Region failover for APIs Limited (DNS) ✅ Automatic, fast
Custom TCP/UDP apps (VoIP, VPN) ❌ ✅
Need static global IPs ❌ ✅

4. Analogy

  • CloudFront = a local warehouse storing copies of your goods (cached web content) so customers nearby get them fast.
  • Global Accelerator = a private expressway that gets customers to your store quickly and reroutes them if one road is blocked.

Global Accelerator would be useful if:

  • The app was not HTTP-based,
  • Needed static IPs, or
  • Required multi-Region failover with near-instant recovery.

😃 That’s actually a pretty good way to think of it — but let’s refine it so you don’t miss key details.

✅ How Global Accelerator is like a Global Load Balancer

  • It gives you static global entry points (two Anycast IPs).
  • It routes users to the closest healthy AWS endpoint (ALB, NLB, EC2, etc.).
  • It automatically fails over to another AWS Region if one Region/endpoint goes unhealthy.
  • It improves latency and availability globally — just like a "super load balancer across Regions".

⚠️ How it’s different from a normal load balancer

  • A classic load balancer (ALB/NLB) only works within a single AWS Region.
  • Global Accelerator works across multiple Regions.
  • It operates at the network/transport layer (L4) — it doesn’t look at HTTP headers or content like an ALB does.
  • It uses the AWS global network to speed up traffic (private backbone, not just DNS).

🔑 Simple analogy

  • ALB/NLB = a traffic cop inside one city (Region).
  • Global Accelerator = a global air traffic control system that gets planes (users) to the best airport (Region) quickly and reroutes them if one closes.

Benefits:

Global reach: Clients automatically routed to the closest healthy region.

Better performance: Traffic enters the AWS backbone at the nearest edge location → avoids the “slow lanes” of the public internet.

Simplified whitelisting: Only two IPs to manage in firewalls.

Cross-region failover: If one region fails, traffic instantly reroutes to another region.

1. The Problem Without Global Accelerator

  • As your application grows, you might run many endpoints (ALBs, NLBs, EC2 instances) across multiple AWS Regions.
  • Each endpoint has its own IP address.

  • That means:

    • You need to manage and update IP addresses in firewalls, client apps, or DNS.
    • If you add/remove instances (scaling, deployment, or failover), the IP addresses change, so you’d have to update everything again.

  • This becomes complex and error-prone, especially for apps where clients cannot be updated often (IoT devices, medical equipment, etc.).

2. What AWS Global Accelerator Does

AWS Global Accelerator solves this by giving you two static IP addresses that never change.
These act as fixed entry points to your global application.

  • You associate your regional resources (ALBs, NLBs, EC2s) with Global Accelerator endpoint groups.
  • Global Accelerator then intelligently routes traffic to the best endpoint (based on proximity, health, and routing policies).
  • To the outside world, your entire app is always reachable through the same two IPs — regardless of how many regions or endpoints are behind it.

3. Key Benefits

  1. Static IPs → Simplified management
  • Instead of whitelisting 100s of changing EC2 IPs, you only whitelist two static IPs in your firewall, DNS, or client apps.
  1. Performance boost
  • Traffic enters the AWS global network backbone at the nearest edge location, reducing latency compared to standard internet routing.
  1. High availability
  • If one endpoint/region becomes unhealthy, Global Accelerator automatically routes traffic to the next healthy one.
  1. Flexible deployments
  • You can add/remove endpoints, do blue/green deployments, or A/B testing without ever changing client IPs.

4. Endpoint Groups

  • Endpoints (ALBs, NLBs, EC2s) are organized into endpoint groups, one per region.

  • Example:

    • Endpoint Group 1 → EC2 instances + ALB in us-east-1
    • Endpoint Group 2 → EC2 instances + ALB in eu-west-1

  • Global Accelerator balances traffic across them based on traffic dials, weights, and health checks.

5. Real-World Example

Imagine a retail IoT application:

  • Thousands of POS (Point-of-Sale) devices in stores connect to your backend.
  • If backend IPs change (new instances, scaling, region failover), updating all POS devices is impossible.

  • With Global Accelerator:

    • Devices always connect to the same two static IPs.
    • Behind the scenes, you can add/remove endpoints, shift traffic between regions, or deploy new versions seamlessly.
Use Case Just Load Balancer With Global Accelerator
App only runs in one region, users mostly local ✅ ALB/NLB is enough Not needed
App runs in multiple regions (global users) ❌ Route 53 latency routing is an option but slower failover ✅ GA gives faster routing + HA
You need static IPs for clients/firewalls/IoT devices ❌ ALB only gives DNS name (IPs can change) ✅ GA provides 2 static IPs
You want better performance for global clients ❌ Internet routing might be inefficient ✅ GA routes over AWS backbone
You need cross-region disaster recovery ❌ ALB works only in-region ✅ GA can failover to another region

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