Merge pull request #241794 from rcdun/nslack/voiceERsquash

Document ExR Microsoft Peering for PSTN services

Author: v-ccolin

articles/expressroute/TOC.yml

@@ -119,6 +119,8 @@
     href: expressroute-qos.md
   - name: Routing Microsoft 365 traffic over ExpressRoute 
     href: using-expressroute-for-microsoft365.md
+  - name: Routing Microsoft PSTN traffic over ExpressRoute
+    href: using-expressroute-for-microsoft-pstn.md
   - name: High Availability - Design
     href: designing-for-high-availability-with-expressroute.md
   - name: Disaster Recovery - Design

articles/expressroute/expressroute-circuit-peerings.md

@@ -6,7 +6,7 @@ author: duongau
 
 ms.service: expressroute
 ms.topic: conceptual
-ms.date: 09/19/2022
+ms.date: 09/06/2023
 ms.author: duau 
 
 ---
@@ -69,7 +69,7 @@ You can connect more than one virtual network to the private peering domain. Rev
 
 [!INCLUDE [expressroute-office365-include](../../includes/expressroute-office365-include.md)]
 
-Connectivity to Microsoft online services (Microsoft 365 and Azure PaaS services) occurs through Microsoft peering. We enable bi-directional connectivity between your WAN and Microsoft cloud services through the Microsoft peering routing domain. You must connect to Microsoft cloud services only over public IP addresses that are owned by you or your connectivity provider and you must adhere to all the defined rules. For more information, see the [ExpressRoute prerequisites](expressroute-prerequisites.md) page.
+Connectivity to Microsoft online services (Microsoft 365, Azure PaaS services and Microsoft PSTN services) occurs through Microsoft peering. We enable bi-directional connectivity between your WAN and Microsoft cloud services through the Microsoft peering routing domain. You must connect to Microsoft cloud services only over public IP addresses that are owned by you or your connectivity provider and you must adhere to all the defined rules. For more information, see the [ExpressRoute prerequisites](expressroute-prerequisites.md) page.
 
 For more information on services supported, costs, and configuration details, see the [FAQ page](expressroute-faqs.md). For information on the list of connectivity providers offering Microsoft peering support, see the [ExpressRoute locations](expressroute-locations.md) page.
 

articles/expressroute/expressroute-faqs.md

@@ -96,6 +96,7 @@ If your ExpressRoute circuit is enabled for Azure Microsoft peering, you can acc
 * Power BI - Available via an Azure Regional Community, see [here](/power-bi/service-admin-where-is-my-tenant-located) for how to find out the region of your Power BI tenant.
 * Azure Active Directory
 * [Azure DevOps](https://blogs.msdn.microsoft.com/devops/2018/10/23/expressroute-for-azure-devops/) (Azure Global Services community)
+* [Microsoft PSTN services](./using-expressroute-for-microsoft-pstn.md)
 * Azure Public IP addresses for IaaS (Virtual Machines, Virtual Network Gateways, Load Balancers, etc.)  
 * Most of the other Azure services are also supported. Check directly with the service that you want to use to verify support.
 

articles/expressroute/expressroute-routing.md

@@ -5,7 +5,7 @@ services: expressroute
 author: duongau
 ms.service: expressroute
 ms.topic: conceptual
-ms.date: 06/12/2023
+ms.date: 09/06/2023
 ms.author: duau
 ms.custom: references_regions, ignite-2022
 ---
@@ -160,7 +160,7 @@ To enable connectivity to other Azure services and infrastructure services, you
 
 ## <a name="bgp"></a>Support for BGP communities
 
-This section provides an overview of how BGP communities get used with ExpressRoute. Microsoft advertises routes in the private, Microsoft and public (deprecated) peering paths with routes tagged with appropriate community values. The rationale for doing so and the details on community values are describe as followed. Microsoft, however doesn't honor any community values tagged to routes advertised to Microsoft.
+This section provides an overview of how BGP communities get used with ExpressRoute. Microsoft advertises routes in the private, Microsoft and public (deprecated) peering paths with routes tagged with appropriate community values. The rationale for doing so and the details on community values are describe as followed. Microsoft, however, doesn't honor any community values tagged to routes advertised to Microsoft.
 
 For private peering, if you [configure a custom BGP community value](./how-to-configure-custom-bgp-communities.md) on your Azure virtual networks, you'll see this custom value and a regional BGP community value on the Azure routes advertised to your on-premises over ExpressRoute.
 
@@ -246,17 +246,20 @@ In addition to the BGP tag for each region, Microsoft also tags prefixes based o
 | Azure Global Services (1) | 12076:5050 |
 | Azure Active Directory |12076:5060 |
 | Azure Resource Manager |12076:5070 |
-| Other Office 365 Online services** | 12076:5100 |
+| Other Office 365 Online services (2) | 12076:5100 |
 | Microsoft Defender for Identity | 12076:5220 |
+| Microsoft PSTN services (5) | 12076:5250 |
 
 (1) Azure Global Services includes only Azure DevOps at this time.
 
-(2) Authorization required from Microsoft, refer [Configure route filters for Microsoft Peering](how-to-routefilter-portal.md)
+(2) Authorization required from Microsoft. See [Configure route filters for Microsoft Peering](how-to-routefilter-portal.md).
 
 (3) This community also publishes the needed routes for Microsoft Teams services.
 
 (4) CRM Online supports Dynamics v8.2 and below. For higher versions, select the regional community for your Dynamics deployments.
 
+(5) Use of Microsoft Peering with PSTN services is restricted to specific use cases. See [Using ExpressRoute for Microsoft PSTN services](using-expressroute-for-microsoft-pstn.md).
+
 > [!NOTE]
 > Microsoft does not honor any BGP community values that you set on the routes advertised to Microsoft.
 > 

articles/expressroute/using-expressroute-for-microsoft-pstn.md

@@ -0,0 +1,71 @@
+---
+title: 'Using ExpressRoute for Microsoft PSTN Services'
+description:  ExpressRoute circuits can be used for Microsoft PSTN services, including Operator Connect, Azure Communications Gateway, and Azure Communication Services Direct Routing.
+author: nslack
+ms.service: expressroute
+ms.topic: conceptual
+ms.workload: infrastructure-services
+ms.date: 09/06/2023
+ms.author: nickslack
+
+---
+
+# Using ExpressRoute for routing traffic to Microsoft PSTN services
+
+An ExpressRoute circuit provides private connectivity to the Microsoft backbone network. ExpressRoute *Microsoft Peering* connects your on-premises networks with public Microsoft services. You can use Microsoft Peering to provide your voice infrastructure endpoints outside Azure with network connectivity to Microsoft PSTN services (in addition to other Microsoft services).
+
+> [!TIP]
+> ExpressRoute circuits can also be used for *Private Peering*, which allows you to connect to private endpoints of your IaaS deployment in Azure regions.
+
+For more information about ExpressRoute, see the [Introduction to ExpressRoute][ExR-Intro] article.
+
+You can use ExpressRoute Microsoft Peering to connect to the following Microsoft PSTN services:
+
+* Operator Connect (including Calling, Conferencing and Teams Phone Mobile offers)
+* Azure Communications Gateway
+* Azure Communication Services Direct Routing
+
+> [!IMPORTANT]
+> Operator Connect SIP Trunks do not support encryption when using ExpressRoute Microsoft Peering connectivity. 
+
+In this article, you'll learn about why you might consider using ExpressRoute to connect to these Microsoft PSTN services.
+
+## When to use ExpressRoute Microsoft Peering for Microsoft PSTN services
+
+In certain scenarios, using ExpressRoute Microsoft Peering provides better quality for voice calling than using the internet for your traffic. Microsoft owns one of the largest global networks, and the Microsoft network is optimized to achieve the core objective of offering the best network performance. The Microsoft network uses "cold potato" routing, meaning traffic enters and exits as close as possible to client devices/customer networks to reduce network hops and provide optimal quality of service for voice traffic. The Microsoft network is designed with redundancy and is highly available. For more information about architecture optimization, see [How Microsoft builds its fast and reliable global network][MGN].
+
+### For enterprises managing your own PSTN connectivity
+
+If your PSTN traffic is concentrated in multiple global locations and each location has its own ExpressRoute connection, ExpressRoute Microsoft Peering could be suited to you. This architecture is common for users of Direct Routing who have deployed their own SBCs in sites with ExpressRoute connectivity.
+
+### For Communications Services Providers
+
+We recommend that Communications Services Providers use Peering Service Voice interconnect (sometimes also called MAPSV or MAPS Voice) to connect their networks to the Microsoft network. To configure Peering Service Voice interconnection, follow [Internet peering for Peering Service Voice walkthrough](../internet-peering/walkthrough-communications-services-partner.md).
+
+In some cases, using ExpressRoute Microsoft Peering might be preferable as it allows you to:
+
+* Reuse existing ExpressRoute connectivity to your network instead of creating new Peering Service Voice connectivity.
+* Avoid port scarcity at peering locations.
+* Segregate your voice traffic on smaller circuits than the minimum 10-Gbps connections supported by Peering Service Voice interconnects.
+* Make use of 802.1Q tagging.
+
+Operator Connect providers must ensure the architecture used for network connectivity is compliant with the latest Microsoft Teams *Network Connectivity Specification*. This specification is made available to Operator Connect providers during onboarding.
+
+## Configuring Microsoft Peering for use with Microsoft PSTN services
+
+Multiple Microsoft services (including Microsoft PSTN services, Microsoft 365 services and some Azure PaaS offerings) can be connected via Microsoft Peering. With the use of a *Route Filter*, you can select which service prefixes you want Microsoft to advertise over Microsoft Peering to your on-premises network. To configure a suitable Route Filter for Microsoft PSTN services, follow [Configure route filters for Microsoft Peering][ExRRF], setting *Azure SIP Trunking* as an allowed service community.
+
+All Microsoft PSTN services supported for Microsoft Peering use the 52.120.0.0/15 subnet. The Azure SIP Trunking service community refers to this subnet.
+
+> [!NOTE]
+> You must connect to Microsoft cloud services only over public IP addresses that are owned by you or your connectivity provider and you must adhere to all the defined rules. For more information, see the [ExpressRoute prerequisites](./expressroute-prerequisites.md) page.
+
+## Next steps
+
+* [Create ExpressRoute Microsoft Peering][CreatePeering]
+
+<!--Link References-->
+[ExR-Intro]: ./expressroute-introduction.md
+[CreatePeering]: ./expressroute-howto-routing-portal-resource-manager.md
+[MGN]: https://azure.microsoft.com/blog/how-microsoft-builds-its-fast-and-reliable-global-network/
+[ExRRF]: ./how-to-routefilter-portal.md