VPCのtunnel断について

Site-to-Site VPN 接続サービスを利用し、VPNを設定していた。 VPNにはtunnelを2つ設定していた。

今回AWSから以下のメールがあり、tunnelが切断された。 切断されてしまった理由と回復するための手段が知りたい。

You are receiving this message because your VPN Connection vpn-～～in the ap-northeast-1 Region had a momentary lapse of redundancy as one of two tunnel endpoints (Tunnel Outside IP: ～～) was replaced. Connectivity on the second tunnel was not affected during this time. Both tunnels are now operating normally.

Replacements can occur for several reasons, and be initiated either by AWS or when you modify your VPN Connection [1]. AWS-initiated replacement reasons include health, software upgrades, and when underlying hardware is retired.

This replacement was AWS Initiated.

AWS Site-to-Site VPN includes two tunnels so that you can maintain a highly available VPN connection. If you have configured your VPN Customer Gateway to use both tunnels, then your VPN Connection will have utilized the alternate tunnel during the replacement process. For more on tunnel endpoint replacements, please see our documentation (2). If you have not configured your VPN Customer Gateway to use both tunnels, then your VPN Connection may have been interrupted during the replacement. We encourage you to configure your router to use both tunnels. You can obtain the VPN Connection configuration recommendations for several types of VPN devices from the AWS Management Console [3]. On the "Amazon VPC" tab, select "VPN Connections". Then highlight the VPN Connection and choose "Download Configuration".