AWS Global Accelerator uses the concept of network zones to enhance fault tolerance, availability, and performance of your applications globally. Here is a detailed explanation of network zones in Global Accelerator:
**Definition and Purpose
A network zone in Global Accelerator is an isolated unit of physical infrastructure, similar in concept to an AWS Availability Zone but specific to the Global Accelerator service. Each network zone has its own set of physical infrastructure and serves IP addresses from a unique IP subnet. These zones are designed to provide fault isolation and high availability for the static IP addresses assigned to your accelerator[3][5][6].
**Static IP Addresses and Network Zones
When you create a Global Accelerator, AWS allocates two static IPv4 addresses (or four static IPs for dual-stack accelerators) for your accelerator. Each of these static IP addresses is served from a different network zone. This means the two IPs are advertised from separate, independent network zones, which protects your application if one network zone experiences a failure or disruption. For example, if one IP address becomes unreachable due to network issues or IP blocking by certain client networks, client applications can retry using the other healthy IP address from the other network zone[3][5][6][8].
**Physical Isolation and Fault Tolerance
Each network zone is managed independently and has strict change control policies to ensure that updates or changes affect only one network zone at a time. This isolation limits the impact of failures or maintenance activities. Moreover, each network zone is partitioned into multiple cells, which are further isolated units with their own physical hosts and configurations. Customers are associated with pairs of cells in separate network zones, so if one cell is impacted, traffic continues to be served from the other cell in the other network zone, enhancing resilience[5].
**Role in Traffic Routing
Network zones enable Global Accelerator to provide fault-tolerant, high-availability routing by advertising IP addresses from multiple isolated zones. Traffic from users is routed to the closest AWS edge location, where Global Accelerator terminates the TCP connection and forwards it over the AWS global network to the optimal regional endpoint. The use of network zones ensures that if one zone or IP address is unavailable, traffic can failover instantly to the other zoneâs IP address without disruption[3][5][6].
**Summary
- Network zones are isolated physical infrastructure units in AWS Global Accelerator, similar to Availability Zones but specific to the edge network.
- Each accelerator is assigned two static IP addresses, each served from a different network zone to provide fault tolerance.
- Network zones have independent management, physical infrastructure, and IP subnets to isolate failures.
- They are further divided into cells to reduce customer impact from failures.
- Network zones enable instant failover between IP addresses if one zone becomes unavailable, ensuring high availability and resilience for global applications[3][5][6][8].
This design allows AWS Global Accelerator to provide a highly available, performant, and fault-tolerant global traffic routing service for your applications.
Citations:
[1] https://docs.aws.amazon.com/global-accelerator/latest/dg/introduction-how-it-works.html
[2] https://docs.aws.amazon.com/global-accelerator/latest/dg/what-is-global-accelerator.html
[3] https://aws.amazon.com/global-accelerator/features/
[4] https://tutorialsdojo.com/aws-global-accelerator/
[5] https://aws.amazon.com/blogs/networking-and-content-delivery/maximising-application-resiliency-with-aws-global-accelerator/
[6] https://docs.aws.amazon.com/global-accelerator/latest/dg/introduction-components.html
[7] https://boto3.amazonaws.com/v1/documentation/api/1.17.39/reference/services/globalaccelerator.html
[8] https://www.hava.io/blog/what-is-aws-global-accelerator
[9] https://stackoverflow.com/questions/63239840/what-is-the-aws-global-accelerator-eni
[10] https://www.whizlabs.com/blog/aws-global-accelerator/