Resilience in AWS Site-to-Site VPN
The AWS global infrastructure is built around AWS Regions and Availability Zones. AWS Regions provide multiple physically separated and isolated Availability Zones, which are connected with low-latency, high-throughput, and highly redundant networking. With Availability Zones, you can design and operate applications and databases that automatically fail over between zones without interruption. Availability Zones are more highly available, fault tolerant, and scalable than traditional single or multiple data center infrastructures.
For more information about AWS Regions and Availability Zones, see AWS Global
Infrastructure
In addition to the AWS global infrastructure, Site-to-Site VPN offers features to help support your data resiliency and backup needs.
Two tunnels per VPN connection
A Site-to-Site VPN connection consists of two tunnels, each terminating in a different Availability Zone, to provide increased availability to your VPC. If there's a device failure within AWS, your VPN connection automatically fails over to the second tunnel so that your access isn't interrupted. From time to time, AWS also performs routine maintenance on your VPN connection, which may briefly disable one of the two tunnels of your VPN connection. For more information, see Site-to-Site VPN tunnel endpoint replacements. When you configure your customer gateway, it's therefore important that you configure both tunnels.
Redundancy
To protect against a loss of connectivity in case your customer gateway becomes unavailable, you can set up a second Site-to-Site VPN connection. For more information, see the following documentation:
