add note about route filter

Author: duongau

articles/expressroute/how-to-move-peering.md

@@ -5,7 +5,7 @@ services: expressroute
 author: duongau
 ms.service: expressroute
 ms.topic: how-to
-ms.date: 04/07/2023
+ms.date: 03/11/2024
 ms.author: duau
 ---
 
@@ -82,6 +82,9 @@ By default, new Microsoft peering don't advertise any prefixes until a route fil
 
 ![Merge public peering](./media/how-to-move-peering/routefilter.jpg)
 
+> [!NOTE]
+> Public peering advertises all the Azure regions prefixes by default. Whereas, in the Microsoft peering you can select the regions in the route filter associated with Microsoft peering to limit the number of routes advertised to your on-premises network. 
+
 Configure route filters using any of the following articles:
 
 * [Configure route filters for Microsoft peering using Azure portal](how-to-routefilter-portal.md)<br>