Merge pull request #266573 from halkazwini/rs-er

Add a note about ER to ER connectivity

Author: v-regandowner

articles/route-server/expressroute-vpn-support.md

@@ -6,24 +6,29 @@ author: halkazwini
 ms.author: halkazwini
 ms.service: route-server
 ms.topic: concept-article
-ms.date: 08/15/2023
+ms.date: 02/16/2024
+
+#CustomerIntent: As an Azure administrator, I want to deploy Azure Route Server with ExpressRoute and Azure VPN so that routes can be exchanged between the two on-premises networks.
 ---
 
 # Azure Route Server support for ExpressRoute and Azure VPN
 
-Azure Route Server supports not only third-party network virtual appliances (NVA) running on Azure but also seamlessly integrates with ExpressRoute and Azure VPN gateways. You don’t need to configure or manage the BGP peering between the gateway and Azure Route Server. You can enable route exchange between the gateways and Azure Route Server by enabling [branch-to-branch](quickstart-configure-route-server-portal.md#configure-route-exchange) in Azure portal. If you prefer, you can use [Azure PowerShell](quickstart-configure-route-server-powershell.md#route-exchange) or [Azure CLI](quickstart-configure-route-server-cli.md#configure-route-exchange) to enable the route exchange with the Route Server.
+Azure Route Server supports not only third-party network virtual appliances (NVA) in Azure but also seamlessly integrates with ExpressRoute and Azure VPN gateways. You don’t need to configure or manage the BGP peering between the gateway and Azure Route Server. You can enable route exchange between the gateways and Azure Route Server by enabling [branch-to-branch](quickstart-configure-route-server-portal.md#configure-route-exchange) in Azure portal. If you prefer, you can use [Azure PowerShell](quickstart-configure-route-server-powershell.md#route-exchange) or [Azure CLI](quickstart-configure-route-server-cli.md#configure-route-exchange) to enable the route exchange with the Route Server.
 
 [!INCLUDE [downtime note](../../includes/route-server-note-vng-downtime.md)]
 
 ## How does it work?
 
 When you deploy an Azure Route Server along with a virtual network gateway and an NVA in a virtual network, by default Azure Route Server doesn’t propagate the routes it receives from the NVA and virtual network gateway between each other. Once you enable **branch-to-branch** in Route Server, the virtual network gateway and the NVA exchange their routes.
 
-For example, in the following diagram:
+> [!IMPORTANT] 
+> ExpressRoute branch-to-branch connectivity is not supported. If you have two (or more) ExpressRoute circuits connected to the same ExpressRoute virtual network gateway, routes from one circuit are not advertised to the other. If you want to enable on-premises to on-premises connectivity over ExpressRoute, consider configuring ExpressRoute Global Reach. For more information, see [About Azure ExpressRoute Global Reach](../expressroute/expressroute-global-reach.md).
+
+The following diagram shows an example of using Route Server to exchange routes between an ExpressRoute and SDWAN appliance:
 
-* The SDWAN appliance receives from Azure Route Server the route of *On-premises 2*, which is connected to ExpressRoute circuit, along with the route of the virtual network.
+- The SDWAN appliance receives from Azure Route Server the route of *On-premises 2*, which is connected to ExpressRoute circuit, along with the route of the virtual network.
 
-* The ExpressRoute gateway receives from Azure Route Server the route of *On-premises 1*, which is connected to the SDWAN appliance, along with the route of the virtual network.
+- The ExpressRoute gateway receives from Azure Route Server the route of *On-premises 1*, which is connected to the SDWAN appliance, along with the route of the virtual network.
 
 :::image type="content" source="./media/expressroute-vpn-support/expressroute-with-route-server.png" alt-text="Diagram showing ExpressRoute gateway and SDWAN NVA exchanging routes through Azure Route Server.":::
 
@@ -37,10 +42,10 @@ If you enable BGP on the VPN gateway, the gateway learns *On-premises 1* routes
 :::image type="content" source="./media/expressroute-vpn-support/expressroute-and-vpn-with-route-server.png" alt-text="Diagram showing ExpressRoute and VPN gateways exchanging routes through Azure Route Server.":::
 
 > [!NOTE] 
-> When the same route is learned over ExpressRoute, Azure VPN or an SDWAN appliance, the ExpressRoute network will be preferred.
+> When the same route is learned over ExpressRoute, Azure VPN or an SDWAN appliance, the ExpressRoute network will be preferred by default. You can configure routing preference to influence Route Server route selection. For more information, see [Routing preference (preview)](hub-routing-preference.md).
 
-## Next steps
+## Related content
 
-- Learn more about [Azure Route Server](route-server-faq.md).
-- Learn how to [configure Azure Route Server](quickstart-configure-route-server-powershell.md).
-- Learn more about [Azure ExpressRoute and Azure VPN coexistence](../expressroute/how-to-configure-coexisting-gateway-portal.md).
+- [Azure Route Server frequently asked questions (FAQ)](route-server-faq.md).
+- [Configure Azure Route Server](quickstart-configure-route-server-powershell.md).
+- [Azure ExpressRoute and Azure VPN coexistence](../expressroute/how-to-configure-coexisting-gateway-portal.md?toc=/azure/route-server/toc.json).