1. What is Global Accelerator?

AWS Global Accelerator is a networking service that improves the availability and performance of your applications by using the AWS global network. It provides two static anycast IP addresses that route traffic to the optimal AWS endpoint based on health, geography, and routing policies.

Core Concept

Global Accelerator gives you 2 static IPs that act as a fixed entry point to your application. Traffic enters the nearest AWS Edge Location and travels over AWS’s private backbone network to your endpoint. This avoids the public internet for the majority of the journey, reducing latency and improving consistency.

2. How It Works

Without Global Accelerator: User → Internet (many hops, variable latency) → ALB/EC2
With Global Accelerator: User → Nearest Edge Location (short internet hop) → AWS Private Backbone (fast, consistent) → ALB/EC2 in optimal Region
2 Static Anycast IPs → Edge Locations → AWS Backbone → Endpoints

3. Key Characteristics

  1. 2 static anycast IP addresses (fixed, never change)
  2. Traffic enters the closest AWS Edge Location (400+)
  3. Travels over the AWS global private backbone network (not public internet)
  4. Supports: ALB, NLB, EC2 instances, and Elastic IP as endpoints
  5. Endpoints can be in multiple AWS Regions
  6. Built-in health checks with automatic failover (<30 seconds)
  7. DDoS protection via AWS Shield Standard (included)
  8. Works with TCP and UDP (not just HTTP like CloudFront)

4. Global Accelerator Features


Traffic Dials

  1. Control the percentage of traffic directed to each endpoint group (Region)
  2. Use for: blue/green deployment across Regions, gradual migration
  3. Example: US endpoint group = 80%, EU endpoint group = 20%


Endpoint Weights

  1. Control the proportion of traffic to individual endpoints within a group
  2. Example: ALB-1 = weight 200, ALB-2 = weight 100 (ALB-1 gets 2/3 of traffic)


Client Affinity

  1. Route a specific client to the same endpoint consistently
  2. Options: None (default) or Source IP
  3. Useful for: stateful applications that need session persistence

5. CloudFront vs Global Accelerator

CloudFront vs Global Accelerator Decision

"Cacheable HTTP content + edge compute" = CloudFront. "Non-HTTP (TCP/UDP) or need static IPs or no caching needed" = Global Accelerator. "Gaming, IoT, VoIP" = Global Accelerator (UDP support). "Static website, API, video streaming" = CloudFront. "Whitelisting fixed IPs in firewall" = Global Accelerator (2 static IPs).

6. Use Cases

Exam Tip

Global Accelerator: "Static IPs" = Global Accelerator. "UDP support" = GA (not CloudFront). "Gaming, IoT, VoIP" = GA. "Improve performance of non-HTTP app" = GA. "Whitelist IPs in firewall" = GA (2 static IPs). "Cache content at edge" = CloudFront (NOT GA). GA uses AWS backbone for routing, not caching. CloudFront = CDN (caching). GA = network accelerator (routing). Both use Edge Locations.