This page describes recommended topologies and the corresponding availability Service Level Agreement (SLA) for each HA VPN topology. For Classic VPN topologies, see Classic VPN topologies. For more information about Cloud VPN, including both VPN types, see the Cloud VPN overview.
For definitions of terms used on this page, see Key terms.
Overview
HA VPN supports site-to-site VPN in one of the following recommended topologies:
HA VPN to third-party peer VPN gateways. This topology requires two VPN tunnels from the perspective of the HA VPN gateway to achieve the high availability SLA. In this configuration, HA VPN has three typical peer gateway configurations:
- Two separate peer VPN devices, each with its own IP address.
- One peer VPN device with two separate IP addresses.
- One peer VPN device with one IP address.
To determine which topology is most appropriate, check with the vendor of your peer VPN gateway.
HA VPN between Google Cloud VPC networks. In this topology, you can connect two Google Cloud VPC networks by using an HA VPN gateway in each network. The VPC networks can be in the same region or multiple regions.
HA VPN to Compute Engine VM instances. In this topology, you connect an HA VPN gateway to a Compute Engine virtual machine (VM) instance. Your VM instances can be in one zone or multiple zones.
HA VPN over Cloud Interconnect In this topology, you create HA VPN tunnels to carry IPsec-encrypted traffic over VLAN attachments of either Dedicated Interconnect or Partner Interconnect. You can reserve regional internal IP address ranges for your HA VPN gateways. Your peer VPN devices can also have internal IP addresses. For more information and architecture diagrams, see HA VPN over Cloud Interconnect deployment architecture.
Configurations that support 99.99% availability
| Topology | Description | Availability SLA |
|---|---|---|
| HA VPN to peer VPN gateways | Connect an HA VPN gateway to one or two separate peer VPN devices | 99.99% |
| HA VPN between two Google Cloud networks | Connect two Google Cloud VPC networks in a single region by using an HA VPN gateway in each network | 99.99% |
To configure for 99.99% availability for HA VPN connections, configure two tunnels from your HA VPN gateway to your peer VPN gateway or to another HA VPN gateway. Make sure that the peer VPN gateway is also configured to receive 99.99% availability SLA.
Proper configuration means that VPN tunnels must supply adequate redundancy by connecting to all interfaces of the HA VPN gateway and to all interfaces of the peer VPN gateway or other HA VPN gateway.
Configurations that support 99.9% availability
| Topology | Description | Availability SLA |
|---|---|---|
| HA VPN to Compute Engine VM instances in multiple zones | Connect an HA VPN gateway to Compute Engine VM instances with external IP addresses | 99.9% |
| HA VPN to a single Compute Engine VM instance | Connect an HA VPN gateway to only one Compute Engine VM instance with an external IP address | The availability SLA is determined by the availability SLA provided for a single VM instance of memory-optimized machine family for Compute Engine. For more information, see Compute Engine Service Level Agreement (SLA). |
To configure for a 99.9% availability SLA for HA VPN connections in these topologies, configure two from your HA VPN gateway to your peer VPN gateway or to other Google Cloud resources.
Configure HA VPN for more bandwidth
To increase the bandwidth of your HA VPN gateways, add more HA VPN tunnels.
To calculate the number of tunnels you need, use 250,000 packets per second as the sum of inbound and outbound capacity for each tunnel. For example, if you need 600,000 packets per second for a sum of inbound and outbound traffic, you need three pairs of HA VPN tunnels (six tunnels) to help ensure the required bandwidth and failover capacity.
For more information about VPN bandwidth calculations, see Network bandwidth.
Consider the following guidelines when increasing HA VPN bandwidth.
Check VPN tunnel quotas
Unless you are connecting an HA VPN gateway to another HA VPN gateway, each HA VPN gateway supports an unlimited number of VPN tunnels on each interface.
However, the VPN tunnels quota limits the total number of VPN tunnels in your project.
Add HA VPN gateways to add tunnels between two HA VPNs
When you connect an HA VPN gateway to another HA VPN gateway, you can only connect one tunnel per interface, 0 or 1, to the corresponding interface, 0 or 1, on the other HA VPN gateway. In other words, between a pair of HA VPN gateways, you have a maximum of two HA VPN tunnels.
Therefore, to increase the number of VPN tunnels between HA VPN gateways, you must create additional pairs of HA VPN gateways.
Add pairs of VPN tunnels
To increase the bandwidth between HA VPN and an on-premises peer VPN gateway, add VPN tunnel pairs.
For example, to double the bandwidth of an HA VPN gateway that connects to an on-premises peer VPN gateway with two tunnels (one active, one passive), add two more VPN tunnels. Add one more "active" tunnel and one more "passive" tunnel.
The BGP sessions for all four tunnels receive the same prefixes. The two active tunnels receive the prefixes with the same higher priority, and the two passive tunnels receive the prefixes with the same lower priority.
Match interfaces on the peer VPN gateway
You must match the interfaces on your peer VPN gateway to continue receiving an availability SLA.
When doubling the bandwidth of an HA VPN gateway that connects to an on-premises VPN gateway, match the tunnels to the interfaces on the peer VPN gateway. Place the two active tunnels on interface 0 and the two passive tunnels on interface 1. Alternatively, place the two active tunnels on interface 1 and the two passive tunnels on interface 0.
HA VPN to peer VPN gateways
There are three typical peer gateway configurations for HA VPN:
- An HA VPN gateway to two separate peer VPN devices, each with its own IP address
- An HA VPN gateway to one peer VPN device that uses two separate IP addresses
- An HA VPN gateway to one peer VPN device that uses one IP address
To set up any of these configurations, see Create an HA VPN to a peer VPN gateway.
If you deploy an HA VPN gateway with an IPv4 and IPv6 dual-stack type, then your VPN tunnels can support the exchange of IPv6 traffic. IPv6 must also be enabled in the BGP sessions that you create for the VPN tunnels. In this scenario, you can assign IPv6 addresses to the on-premises subnets and VPC subnets in the following topologies.
Two peer VPN devices
If your peer-side gateway is hardware-based, having a second peer-side gateway provides redundancy and failover on that side of the connection. A second physical gateway lets you take one of the gateways offline for software upgrades or other scheduled maintenance. It also protects you if there is a failure in one of the devices.
In this topology, one HA VPN gateway connects to two peer devices. Each peer device has one interface and one external IP address. The HA VPN gateway uses two tunnels, one tunnel to each peer device.
In Google Cloud, the REDUNDANCY_TYPE for this configuration takes the
value TWO_IPS_REDUNDANCY.
The following example provides 99.99% availability.
One peer VPN device with two IP addresses
This topology describes one HA VPN gateway that connects to one peer device that has two separate external IP addresses. The HA VPN gateway uses two tunnels, one tunnel to each external IP address on the peer device.
In Google Cloud, the REDUNDANCY_TYPE for this configuration takes
the value TWO_IPS_REDUNDANCY.
The following example provides 99.99% availability.
One peer VPN device with one IP address
This topology describes one HA VPN gateway that connects to one peer device that has one external IP address. The HA VPN gateway uses two tunnels, both tunnels to the single external IP address on the peer device.
In Google Cloud, the REDUNDANCY_TYPE for this configuration takes the value
SINGLE_IP_INTERNALLY_REDUNDANT.
The following example provides 99.99% availability.
Configure for 99.99% availability
To meet the 99.99% availability SLA on the Google Cloud side, there must be a tunnel from each of the two interfaces on the HA VPN gateway to the corresponding interfaces on the peer gateway.
If the peer gateway has two interfaces, then configuring two tunnels, one from each peer interface to each HA VPN gateway interface, meets the requirements for the 99.99% availability SLA. A full mesh configuration is not required for 99.99% availability SLA on the Google Cloud side. In this case, a full mesh is defined as two tunnels from each HA VPN interface to each of the two interfaces on the peer gateway. To confirm if your VPN vendor recommends a full mesh configuration, see the documentation for your peer (on-premises) VPN device or contact your VPN vendor.
In configurations with two peer interfaces, tunnels on each of the following interfaces on the HA VPN gateway match the corresponding interfaces on the peer gateway or gateways:
- HA VPN
interface 0to peerinterface 0 - HA VPN
interface 1to peerinterface 1
Examples are shown in the diagrams for two peer devices, two interfaces and one peer device, two interfaces.
If there is only one peer interface on one peer gateway, each tunnel from each HA VPN gateway interface must connect to the single peer interface. See the diagram for one peer device, one interface.
The following example does not provide 99.99% availability:
- HA VPN
interface 0to peerinterface 0
HA VPN between Google Cloud networks in the same region
You can connect two Google Cloud VPC networks together by using an HA VPN gateway in each network. Each HA VPN gateway identifies the other gateway by its name.
If you deploy two HA VPN gateways with the IPv4 and IPv6 dual-stack type, then your VPN tunnels can support the exchange of IPv6 traffic. IPv6 must also be enabled in the BGP sessions that you create for the VPN tunnels. In this scenario, you can assign IPv6 addresses to the VPC subnets in the following topology.
The following example provides 99.99% availability.
To set up this configuration, see Create two fully configured HA VPN gateways that connect to each other.
Configure for 99.99% availability
To help ensure 99.99% availability, configure each HA VPN gateway with two tunnels so that both of the following are true:
Tunnel 0connectsinterface 0on one HA VPN gateway tointerface 0on the other HA VPN gateway.Tunnel 1connectsinterface 1on one HA VPN gateway tointerface 1on the other HA VPN gateway.
HA VPN between Google Cloud networks in different regions
You can connect two VPC networks in different regions by using HA VPN gateways. The HA VPN gateways can belong to the same or different organizations, and each HA VPN gateway identifies the other gateway by its name.
The following example provides 99.9% availability.
We recommend using the HA VPN between Google Cloud networks in the same region topology because it provides higher availability, unless you have a requirement for the gateways to be in two different regions.
To set up this configuration, see Create two fully configured HA VPN gateways that connect to each other.
Configure for 99.9% availability
To help ensure 99.9% availability, configure each HA VPN gateway with two tunnels so that both of the following are true:
Tunnel 0connectsinterface 0on one HA VPN gateway tointerface 0on the other HA VPN gateway.Tunnel 1connectsinterface 1on one HA VPN gateway tointerface 1on the other HA VPN gateway.
HA VPN to Compute Engine VM instances in different zones
HA VPN lets you connect a HA VPN gateway to Compute Engine virtual machine (VM) instances that work as a network virtual appliance and runs an IPsec VPN implementation. This topology provides 99.9% availability SLA when configured correctly.
In this topology, an HA VPN gateway can connect to two Compute Engine VM instances. The HA VPN gateway and the VMs are in two different VPCs. The two VMs are in different zones, with each VM having an external IP address. The VM instances behave like VPN peer devices.
This topology is especially useful when you want to connect HA VPN to a third-party network virtual appliance VM hosted in Google Cloud. For example, by using this topology, you can upgrade one of the network virtual appliance VMs without any downtime to the VPN connection.
In the diagram, the HA VPN gateway is in a Virtual Private Cloud
network named network-a, and the two VMs are in network-b. Both Virtual Private Cloud
networks are located in us-central1. The HA VPN
gateway in network-a is configured with the external IP addresses of each of
the VMs in network-b. You can also have the HA VPN gateway and
the VMs in two different regions. We recommend that you use this topology to
improve availability.
The following example provides 99.9% availability.
To set up this configuration, see Connect HA VPN to Compute Engine VMs.
Configure for 99.9% availability
To meet the 99.9% SLA, there must be at least two tunnels from each of the two interfaces on the HA VPN gateway to the corresponding interfaces on each of the VMs. We recommend that you use this topology to get higher availability.
Two tunnels on each of the following interfaces on the HA VPN gateway connect to the interfaces on the VM:
Tunnel 0frominterface 0tous-central1-vm-ain theus-central1-azoneTunnel 1frominterface 1tous-central1-vm-ain theus-central1-azoneTunnel 2frominterface 0tous-central1-vm-bin theus-central1-bzoneTunnel 3frominterface 1tous-central1-vm-bin theus-central1-bzone
HA VPN to a single Compute Engine VM instance
HA VPN lets you connect a HA VPN gateway to a Compute Engine virtual machine (VM) instance that works as a network virtual appliance and runs an IPsec VPN implementation. The HA VPN gateway and the VM are in two different VPCs. The VM has an external IP address.
Overall availability is determined by the availability SLA provided for a single VM instance of memory-optimized machine family for Compute Engine. For more information, see Compute Engine Service Level Agreement (SLA).
To set up this configuration, see Connect HA VPN to Compute Engine VMs.
Configure for 99.9% availability
To meet the 99.9% availability SLA, there must be two tunnels from each of the two interfaces on the HA VPN gateway to the interface of the Compute Engine VM.
Two tunnels on each of the following interfaces on the HA VPN gateway connect to the interfaces on VM:
Tunnel 0frominterface 0tous-central1-vm-ain theus-central1-azoneTunnel 1frominterface 1tous-central1-vm-ain theus-central1-azone
What's next
- To use high-availability and high-throughput scenarios or multiple subnet scenarios, see Advanced configurations.
- To help you solve common issues that you might encounter when using Cloud VPN, see Troubleshooting.