AWS Global Accelerator handles traffic routing to multiple regions by providing a set of static Anycast IP addresses that serve as a consistent entry point for your application. These IP addresses are advertised from AWS edge locations worldwide, enabling user traffic to enter the AWS global network at the closest edge location to the user. From there, Global Accelerator routes the traffic over the AWS global network to the optimal endpoint based on several factors including geographic proximity, endpoint health, and configured traffic weights[4][7][10].
Key Mechanisms of Traffic Routing Across Multiple Regions
**1. Static Anycast IP Addresses:
When you create an accelerator, AWS assigns two static Anycast IP addresses from different network zones. These IPs do not change even if the underlying infrastructure changes, providing a fixed entry point for your users globally[7][10].
**2. Endpoint Groups and Listeners:
You configure listeners on the accelerator that specify ports and protocols for incoming traffic. Endpoints (such as Network Load Balancers, Application Load Balancers, or EC2 instances) are grouped by region into endpoint groups. Each endpoint group corresponds to a specific AWS Region, allowing granular control over traffic distribution[5][7].
**3. Traffic Routing Based on Health and Proximity:
Global Accelerator continuously monitors the health of endpoints using health checks. It routes traffic only to healthy endpoints and prefers endpoints that are geographically closer to the user to minimize latency. If an endpoint or region becomes unhealthy, traffic is automatically routed to other healthy endpoints in other regions, providing failover capability[5][6][7].
**4. Traffic Dial and Weight Configuration:
You can control the proportion of traffic routed to each region by configuring traffic dials or weights on endpoint groups. This allows you to implement active-active (load sharing) or active-standby (failover) multi-region architectures. For example, you can send 70% of traffic to one region and 30% to another or have one region handle all traffic until it becomes unhealthy, at which point traffic shifts to the standby region[5][6].
**5. Custom Routing Accelerators for Deterministic Routing:
For applications requiring deterministic routing (e.g., multiplayer gaming or VoIP), Global Accelerator supports custom routing accelerators. These map specific ports on the accelerator to particular EC2 instance private IP addresses and ports in one or more regions. This allows your application logic (like matchmaking) to route multiple users to specific EC2 instances or game sessions across regions while still benefiting from the global network performance[1][2][8].
Summary of Multi-Region Traffic Handling
- Users connect to Global Acceleratorâs static Anycast IPs.
- Traffic enters the AWS global network at the nearest edge location.
- Global Accelerator routes traffic to the best endpoint based on health, geography, and configured traffic weights.
- Traffic can be distributed across multiple AWS regions, supporting both active-active and active-standby failover models.
- Custom routing accelerators enable deterministic traffic routing to specific EC2 instances and ports across regions.
- Failover is automatic: unhealthy endpoints are removed from routing until they recover.
This approach improves application availability, performance, and resiliency by leveraging AWSâs global network and regional endpoint health monitoring[4][5][6][7][10].
Citations:
[1] https://docs.aws.amazon.com/global-accelerator/latest/dg/about-custom-routing-how-it-works.html
[2] https://aws.amazon.com/blogs/networking-and-content-delivery/introducing-aws-global-accelerator-custom-routing-accelerators/
[3] https://docs.aws.amazon.com/global-accelerator/latest/dg/about-custom-routing-listeners.html
[4] https://cloudchipr.com/blog/aws-global-accelerator
[5] https://repost.aws/questions/QUo8q_KZ2fTz2PjaiJc9ztEQ/using-aws-global-accelerator-service-to-distribute-traffic-across-multiple-regions
[6] https://aws.amazon.com/blogs/networking-and-content-delivery/deploying-multi-region-applications-in-aws-using-aws-global-accelerator/
[7] https://www.applify.co/blog/what-is-aws-global-accelerator
[8] https://docs.aws.amazon.com/global-accelerator/latest/dg/about-custom-routing-accelerators.html
[9] https://d1.awsstatic.com/events/reinvent/2019/REPEAT_2_Using_AWS_Global_Accelerator_for_multi-region_applications_NET202-R2.pdf
[10] https://aws.amazon.com/blogs/aws/new-aws-global-accelerator-for-availability-and-performance/