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Author: cherylmc

articles/vpn-gateway/about-active-active-gateways.md

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 # About active-active mode VPN gateways
 
-Azure VPN gateways can be configured as active-standby or active-active. This article helps you better understand active-active gateway configurations and why you might want to create a gateway in active-active mode.
+Azure VPN gateways can be configured as active-standby or active-active. This article explains active-active mode gateway configurations and highlights the benefits of using active-active mode.
 
 ## Why create an active-active gateway?
 
-VPN gateways consist of two instances in an active-standby configuration unless you specify active-active mode. In active-standby mode, for any planned maintenance or unplanned disruption that happens to the active instance, behavior is as follows:
+VPN gateways consist of two instances in an active-standby configuration unless you specify active-active mode. In active-standby mode, during any planned maintenance or unplanned disruption affecting the active instance, the following behavior occurs:
 
 * **S2S and VNet-to-VNet**: The standby instance takes over automatically (failover), and resumes the site-to-site (S2S) VPN or VNet-to-VNet connections. This switch over causes a brief interruption. For planned maintenance, connectivity is restored quickly. For unplanned issues, the connection recovery is longer.
 * **P2S**: For point-to-site (P2S) VPN client connections to the gateway, P2S connections are disconnected. Users need to reconnect from the client machines.
 
-To avoid this interruption, you can always create your gateway in **active-active** mode, or  you can change an active-standby gateway to active-active.
+To avoid interruptions, create your gateway in **active-active** mode, or switch an active-standby gateway to active-active.
 
 ### Active-active design
 
 In an active-active configuration for a S2S connection, both instances of the gateway VMs establish S2S VPN tunnels to your on-premises VPN device, as shown the following diagram:
 
 :::image type="content" source="./media/vpn-gateway-highlyavailable/active-active.png" alt-text="Diagram shows an on-premises site with private IP subnets and an on-premises gateway connected to two VPN gateway instances.":::
 
-In this configuration, each Azure gateway instance has a unique public IP address, and each will establish an IPsec/IKE S2S VPN tunnel to your on-premises VPN device specified in your local network gateway and connection. Both VPN tunnels are actually part of the same connection. You'll still need to configure your on-premises VPN device to accept or establish two S2S VPN tunnels, one for each gateway VM instance. P2S connections using active-active mode don't require any special additional configuration.
+In this configuration, each Azure gateway instance has a unique public IP address, and each will establish an IPsec/IKE S2S VPN tunnel to the on-premises VPN device. Both tunnels are part of the same connection. Configure your on-premises VPN device to accept two S2S VPN tunnels, one for each gateway instance. P2S connections to gateways in active-active mode require no additional configuration.
 
-Because the Azure gateway instances are in an active-active configuration, the traffic from your Azure virtual network to your on-premises network are routed through both tunnels simultaneously, even if your on-premises VPN device might favor one tunnel over the other. For a single TCP or UDP flow, Azure attempts to use the same tunnel when sending packets to your on-premises network. However, your on-premises network could use a different tunnel to send packets to Azure.
+In an active-active configuration, Azure routes traffic from your virtual network to your on-premises network through both tunnels simultaneously, even if your on-premises VPN device might favor one tunnel over the other. For a single TCP or UDP flow, Azure attempts to use the same tunnel when sending packets to your on-premises network. However, your on-premises network might use a different tunnel to send packets back to Azure.
 
 When a planned maintenance or unplanned event happens to one gateway instance, the IPsec tunnel from that instance to your on-premises VPN device will be disconnected. The corresponding routes on your VPN devices should be removed or withdrawn automatically so that the traffic will be switched over to the other active IPsec tunnel. On the Azure side, the switch over will happen automatically from the affected instance to the other active instance.
 
@@ -43,7 +43,7 @@ The most reliable design option is to combine the active-active gateways on both
 
 :::image type="content" source="./media/vpn-gateway-highlyavailable/dual-redundancy.png" alt-text="Diagram shows a Dual Redundancy scenario.":::
 
-In this configuration, you create and set up the Azure VPN gateway in an active-active configuration, and create two local network gateways and two connections for your two on-premises VPN devices. The result is a full mesh connectivity of four IPsec tunnels between your Azure virtual network and your on-premises network.
+In this configuration, you create and set up the Azure VPN gateway in active-active mode. You create two local network gateways and two connections for your two on-premises VPN devices. The result is a full mesh connectivity of four IPsec tunnels between your Azure virtual network and your on-premises network.
 
 All gateways and tunnels are active from the Azure side, so the traffic is spread among all four tunnels simultaneously, although each TCP or UDP flow will follow the same tunnel or path from the Azure side. Even though by spreading the traffic, you might see slightly better throughput over the IPsec tunnels, the primary goal of this configuration is for high availability. And due to the statistical nature of the spreading, it's difficult to provide the measurement on how different application traffic conditions affect the aggregate throughput.
 
@@ -62,7 +62,7 @@ An active-active gateway has slightly different configuration requirements than
 
 ## Reset an active-active gateway
 
-If you need to reset an active-active gateway, you can reset both instances using the portal. You can also use PowerShell or CLI to reset each gateway instance separately using instance VIPS. See [Reset a connection or a gateway](reset-gateway.md#ps).
+If you need to reset an active-active gateway, you can reset both instances using the portal. You can also use PowerShell or CLI to reset each gateway instance separately using instance VIPs. See [Reset a connection or a gateway](reset-gateway.md#ps).
 
 ## Next steps