This page describes advanced configuration details for the following scenarios:
- High-availability VPNs
- High-throughput VPNs
- Multiple subnet VPNs
To learn about the basic concepts of Cloud VPN, see the Cloud VPN overview .
Order of routes
You can create a VPN tunnel that has the same IP range as another tunnel, a subset of the other tunnel's range, or a superset of the other tunnel's range.
For details, see Order of routes .
Configure IKE, including multiple subnet support
In Supported IKE ciphers , you can find details about how Cloud VPN supports multiple IKE ciphers.
In Networks and tunnel routing , you can find information about supported Virtual Private Cloud (VPC) networks and routing options, including traffic selectors.
UDP encapsulation
Cloud VPN only supports one-to-one NAT by using UDP encapsulation for NAT-Traversal (NAT-T). NAT-T is required so that IPsec traffic can reach destinations without external (public) IP addresses behind the NAT. One-to-many NAT and port-based address translation are not supported. In other words, Cloud VPN cannot connect to multiple peer VPN gateways that share a single external IP address.
For more details about VPN gateways behind one-to-one NAT, see On-premises gateways behind NAT on the Troubleshooting page.
Maximum transmission unit (MTU) considerations
The Cloud VPN MTU size is 1460 bytes. For a description of how to configure your peer VPN gateway to support this MTU size if required, see MTU considerations .
High-availability VPNs, high-throughput VPNs, and failover
HA VPN is the recommended method of implementing high-availability VPNs and high-throughput VPNs. If your peer VPN gateway supports BGP, you can configure an HA VPN gateway with a 99.99% uptime SLA by using an active/active or active/passive tunnel configuration.
For Classic VPN gateways, you can provide VPN redundancy and failover by using these throughput and load balancing options . However, with this configuration, you receive a 99.9% availability SLA.
What's next
- To learn about the basic concepts of Cloud VPN, see the Cloud VPN overview .
- To help you solve common issues that you might encounter when using Cloud VPN, see Troubleshooting .
