Merge pull request #192980 from charwen/patch-313

Added a FAQ

Author: PRMerger10

articles/route-server/route-server-faq.md

@@ -5,7 +5,7 @@ services: route-server
 author: duongau
 ms.service: route-server
 ms.topic: article
-ms.date: 01/26/2022
+ms.date: 03/25/2022
 ms.author: duau
 ---
 
@@ -79,7 +79,7 @@ No, Azure Route Server supports only 16-bit (2 bytes) ASNs.
 
 ### Can I associate a User Defined Route (UDR) to the RouteServerSubnet?
 
-No, Azure Route Server doesn't support configuring a UDR on the RouteServerSubnet.
+No, Azure Route Server doesn't support configuring a UDR on the RouteServerSubnet. It should be noted that Azure Route Server does not route any data traffic between NVAs and VMs.
 
 ### Can I associate a Network Security group (NSG) to the RouteServerSubnet?
 
@@ -97,6 +97,10 @@ No. System routes for traffic related to virtual network, virtual network peerin
 
 You can still use Route Server to direct traffic between subnets in different virtual networks to flow using the NVA. The only possible design that may work is one subnet per "spoke" virtual network and all virtual networks are peered to a "hub" virtual network, but this is very limiting and needs to take into scaling considerations and Azure's maximum limits on virtual networks vs subnets.
 
+### Can Azure Route Server filter out routes from NVAs?
+
+Azure Route Server supports ***NO_ADVERTISE*** BGP Community. If an NVA advertises routes with this community string to the route server, the route server won't advertise it to other peers including the ExpressRoute gateway. This feature can help reduce the number of routes to be sent from Azure Route Server to ExpressRoute.
+
 ## <a name = "limitations"></a>Route Server Limits
 
 Azure Route Server has the following limits (per deployment).