Merge pull request #313203 from duongau/expressroute-freshness-review-560387-batch4

Expressroute freshness review - batch 4

Author: JamesJBarnett

articles/expressroute/design-architecture-for-resiliency.md

@@ -1,11 +1,10 @@
 ---
 title: Design and architect Azure ExpressRoute for resiliency
 description: Learn how to design and architect Azure ExpressRoute for resiliency to ensure high availability and reliability in your network connections between on-premises and Azure.
-services: expressroute
 author: duongau
 ms.service: azure-expressroute
 ms.topic: concept-article
-ms.date: 07/16/2024
+ms.date: 03/12/2026
 ms.author: duau
 ms.custom: ai-usage
 # Customer intent: As a network architect, I want to design Azure ExpressRoute for maximum resiliency, so that I can ensure high availability and reliability for our on-premises connections to Azure, supporting critical workloads without interruption.
@@ -31,7 +30,7 @@ There are three ExpressRoute resiliency architectures that can be utilized to en
 
 ### Maximum resiliency
 
-The Maximum resiliency architecture in ExpressRoute is structured to eliminate any single point of failure within the Microsoft network path. This setup is achieved by configuring a pair of circuits across two distinct locations for site diversity with ExpressRoute. The objective of Maximum resiliency is to enhance reliability, resiliency, and availability, as a result ensuring the highest level of resilience for business and/or mission-critical workloads. For such operations, we recommend that you configure maximum resiliency. This architectural design is recommended as part of the [Well Architected Framework](/azure/well-architected/service-guides/azure-expressroute#reliability) under the reliability pillar. The ExpressRoute engineering team developed a [guided portal experience](expressroute-howto-circuit-portal-resource-manager.md?pivots=expressroute-preview) to assist you in configuring maximum resiliency.
+The Maximum resiliency architecture in ExpressRoute is structured to eliminate any single point of failure within the Microsoft network path. This setup is achieved by configuring a pair of circuits across two distinct locations for site diversity with ExpressRoute. The objective of Maximum resiliency is to enhance reliability, resiliency, and availability, as a result ensuring the highest level of resilience for business and/or mission-critical workloads. For such operations, Microsoft recommends that you configure maximum resiliency. This architectural design is recommended as part of the [Well Architected Framework](/azure/well-architected/service-guides/azure-expressroute#reliability) under the reliability pillar. The ExpressRoute engineering team developed a [guided portal experience](expressroute-howto-circuit-portal-resource-manager.md?pivots=expressroute-preview) to assist you in configuring maximum resiliency.
 
 :::image type="content" source="./media/expressroute-howto-circuit-portal-resource-manager/maximum-resiliency.png" alt-text="Diagram of maximum resiliency for an ExpressRoute connection.":::
 
@@ -43,7 +42,7 @@ High resiliency, also referred to as ExpressRoute Metro, enables the use of mult
 
 ### Standard resiliency
 
-Standard resiliency in ExpressRoute is a single circuit with two connections configured at a single site. Built-in redundancy (Active-Active) is configured to facilitate failover across the two connections of the circuit. Today, ExpressRoute offers two connections at a single peering location. If a failure happens at this site, users might experience loss of connectivity to their Azure workloads. This configuration is also known as *single-homed* as it represents users with an ExpressRoute circuit configured with only one peering location. This configuration is considered the *least* resilient and **not recommended** for business or mission-critical workloads because it doesn't provide site resiliency.
+Standard resiliency in ExpressRoute is a single circuit with two connections configured at a single site. Built-in redundancy (Active-Active) is configured to facilitate failover across the two connections of the circuit. ExpressRoute offers two connections at a single peering location. If a failure happens at this site, users might experience loss of connectivity to their Azure workloads. This configuration is also known as *single-homed* as it represents users with an ExpressRoute circuit configured with only one peering location. This configuration is considered the *least* resilient and **not recommended** for business or mission-critical workloads because it doesn't provide site resiliency.
 
 :::image type="content" source="./media/design-architecture-for-resiliency/standard-resiliency.png" alt-text="Diagram illustrating a single ExpressRoute circuit, with each link configured at a single peering location.":::
 
@@ -53,11 +52,11 @@ Standard resiliency in ExpressRoute is a single circuit with two connections con
 
 Azure offers several features to ensure regional resiliency. One such feature is [availability zones](/azure/reliability/availability-zones-overview). Availability zones protect applications and data from data center failures by spanning across multiple physical locations within a region. Regions and availability zones are central to your application design and resiliency strategy. By utilizing availability zones, you can achieve higher availability and resilience in your deployments. For more information, see [Regions & availability zones](/azure/reliability/overview).
 
-We recommend deploying your [ExpressRoute Virtual Network Gateways](expressroute-about-virtual-network-gateways.md) as zone redundant across availability zones within a region. These availability zones are separate physical locations with independent infrastructure (power, cooling, and networking). The purpose is to protect your on-premises network connectivity to Azure from zone level failures. [Zone-redundant ExpressRoute gateways](../vpn-gateway/about-zone-redundant-vnet-gateways.md?toc=%2Fazure%2Fexpressroute%2Ftoc.json) provide resiliency, scalability, and higher availability for accessing mission-critical services on Azure. 
+Microsoft recommends deploying your [ExpressRoute Virtual Network Gateways](expressroute-about-virtual-network-gateways.md) as zone redundant across availability zones within a region. These availability zones are separate physical locations with independent infrastructure (power, cooling, and networking). The purpose is to protect your on-premises network connectivity to Azure from zone level failures. [Zone-redundant ExpressRoute gateways](../vpn-gateway/about-zone-redundant-vnet-gateways.md?toc=%2Fazure%2Fexpressroute%2Ftoc.json) provide resiliency, scalability, and higher availability for accessing mission-critical services on Azure. 
 
 Equipment failures or disasters in regional and zonal data centers can affect ExpressRoute gateway deployments in virtual networks. If gateways aren't deployed as zone-redundant, such failures within an Azure data center can affect the ability for users to access their Azure workloads.  
 
-If you have an existing non-zone redundant ExpressRoute gateways, there's now the ability to [migrate to an availability zone enabled gateway](gateway-migration.md).
+If you have an existing non-zone redundant ExpressRoute gateways, there's the ability to [migrate to an availability zone enabled gateway](gateway-migration.md).
 
 ## Recommendations
 
@@ -76,7 +75,7 @@ During the initial planning phase, it's crucial to determine whether to configur
 
 #### Evaluate the resiliency of multi-site redundant ExpressRoute circuits
 
-After deploying multi-site redundant ExpressRoute circuits with [maximum resiliency](expressroute-howto-circuit-portal-resource-manager.md), it's essential to ensure that on-premises routes are advertised over the redundant circuits to fully utilize the benefits of multi-site redundancy. To evaluate the resiliency and test the failover of redundant circuits and routes Learn more here. 
+After deploying multi-site redundant ExpressRoute circuits with [maximum resiliency](expressroute-howto-circuit-portal-resource-manager.md), it's essential to ensure that on-premises routes are advertised over the redundant circuits to fully utilize the benefits of multi-site redundancy. To evaluate the resiliency and test the failover of redundant circuits and routes, see [Evaluate ExpressRoute circuit resiliency](evaluate-circuit-resiliency.md). 
 
 #### Plan for active-active configuration
 
@@ -108,7 +107,7 @@ To maximize availability, both the customer and service provider segments on you
 
 #### Plan for geo-redundancy
 
-For disaster recovery planning, we recommend setting up ExpressRoute circuits in multiple peering locations and regions. ExpressRoute circuits can be created in the same metropolitan area or different metropolitan areas, and different service providers can be used for diverse paths through each circuit. Geo-redundant ExpressRoute circuits are utilized to create a robust backend network connectivity for disaster recovery. To learn more, see [Designing for high availability](designing-for-high-availability-with-expressroute.md).
+For disaster recovery planning, Microsoft recommends setting up ExpressRoute circuits in multiple peering locations and regions. ExpressRoute circuits can be created in the same metropolitan area or different metropolitan areas, and different service providers can be used for diverse paths through each circuit. Geo-redundant ExpressRoute circuits are utilized to create a robust backend network connectivity for disaster recovery. To learn more, see [Designing for high availability](designing-for-high-availability-with-expressroute.md).
 
 > [!NOTE] 
 > Using site-to-site VPN as a backup solution for ExpressRoute connectivity is not recommended when dealing with latency-sensitive, mission-critical, or bandwidth-intensive workloads. In such cases, it's advisable to design for disaster recovery with ExpressRoute multi-site resiliency to ensure maximum availability.
@@ -124,7 +123,7 @@ Virtual Network (VNet) Peering provides a more efficient and direct method, enab
 
 #### Configure monitoring & alerting for ExpressRoute circuits 
 
-As a baseline, we recommend configuring [Network Insights](expressroute-network-insights.md) within Azure Monitor to view all ExpressRoute circuit metrics, including ExpressRoute Direct and Global Reach. Within the circuits card you can visualize topologies and dependencies for peerings, connections, and gateways. The insights available for circuits include availability, throughput, and packet drops.
+As a baseline, Microsoft recommends configuring [Network Insights](expressroute-network-insights.md) within Azure Monitor to view all ExpressRoute circuit metrics, including ExpressRoute Direct and Global Reach. Within the circuits card you can visualize topologies and dependencies for peerings, connections, and gateways. The insights available for circuits include availability, throughput, and packet drops.
 
 #### Configure service health alerts for ExpressRoute circuit maintenance notifications 
 

articles/expressroute/designing-for-high-availability-with-expressroute.md

@@ -1,11 +1,10 @@
 ---
 title: 'Azure ExpressRoute: Designing for high availability'
 description: This page provides architectural recommendations for high availability while using Azure ExpressRoute.
-services: expressroute
 author: duongau
 ms.service: azure-expressroute
 ms.topic: concept-article
-ms.date: 11/18/2024
+ms.date: 03/16/2026
 ms.author: duau
 # Customer intent: As a network architect, I want to design a high availability Azure ExpressRoute setup, so that I can ensure robust and uninterrupted connectivity for my organization's critical applications and services.
 ---
@@ -21,25 +20,25 @@ Azure ExpressRoute is designed for high availability, providing carrier-grade pr
 
 The following figure illustrates the recommended way to connect using an Azure ExpressRoute circuit to maximize availability.
 
-[![1]][1]
+:::image type="content" source="./media/designing-for-high-availability-with-expressroute/exr-reco.png" alt-text="Diagram of the recommended way to connect using Azure ExpressRoute for high availability.":::
 
 For high availability, it's essential to maintain redundancy throughout the end-to-end network. This means maintaining redundancy within your on-premises network and not compromising redundancy within your service provider network. At a minimum, this involves avoiding single points of network failure. Redundant power and cooling for network devices further improve high availability.
 
 ### First mile physical layer design considerations
 
 If you terminate both the primary and secondary connections of an Azure ExpressRoute circuit on the same Customer Premises Equipment (CPE), you compromise high availability within your on-premises network. Additionally, configuring both connections using the same port of a CPE forces the partner to compromise high availability on their network segment. This can occur by terminating the two connections under different subinterfaces or merging the two connections within the partner network, as illustrated below.
 
-[![2]][2]
+:::image type="content" source="./media/designing-for-high-availability-with-expressroute/suboptimal-lastmile-connectivity.png" alt-text="Diagram of suboptimal last mile connectivity for ExpressRoute circuits.":::
 
 Terminating the primary and secondary connections of an Azure ExpressRoute circuit in different geographical locations can compromise network performance. If traffic is actively load-balanced across connections terminated in different locations, substantial differences in network latency between the two paths can result in suboptimal performance.
 
-For geo-redundant design considerations, see [Designing for disaster recovery with Azure ExpressRoute][DR].
+For geo-redundant design considerations, see [Designing for disaster recovery with Azure ExpressRoute](./designing-for-disaster-recovery-with-expressroute-privatepeering.md).
 
 ### Active-active connections
 
 Microsoft network operates the primary and secondary connections of Azure ExpressRoute circuits in active-active mode. However, you can force the redundant connections to operate in active-passive mode through your route advertisements. Advertising more specific routes and BGP AS path prepending are common techniques to prefer one path over the other.
 
-To improve high availability, it's recommended to operate both connections in active-active mode. This allows Microsoft network to load balance traffic across the connections on a per-flow basis.
+To improve high availability, Microsoft recommends operating both connections in active-active mode. This allows Microsoft network to load balance traffic across the connections on a per-flow basis.
 
 Running connections in active-passive mode risks both connections failing if the active path fails. Common causes for failure include lack of active management of the passive connection and passive connection advertising stale routes.
 
@@ -52,7 +51,7 @@ Alternatively, running connections in active-active mode results in only about h
 
 Microsoft peering is designed for communication between public endpoints. Typically, on-premises private endpoints are Network Address Translated (NATed) with public IPs on the customer or partner network before communicating over Microsoft peering. Using both primary and secondary connections in an active-active setup affects how quickly you recover from a failure in one of the connections. Two different NAT options are illustrated below:
 
-[![3]][3]
+:::image type="content" source="./media/designing-for-high-availability-with-expressroute/nat-options.png" alt-text="Diagram of NAT options for Microsoft peering with ExpressRoute.":::
 
 #### Option 1:
 
@@ -67,7 +66,7 @@ A common NAT pool is used before splitting traffic between the primary and secon
 The NAT pool remains reachable even if the primary or secondary connection fails, allowing the network layer to reroute packets and recover faster.
 
 > [!NOTE]
-> * If using NAT option 1 (independent NAT pools for primary and secondary connections) and mapping a port of an IP address from one NAT pool to an on-premises server, the server will not be reachable via the Azure ExpressRoute circuit if the corresponding connection fails.
+> * If using NAT option 1 (independent NAT pools for primary and secondary connections) and mapping a port of an IP address from one NAT pool to an on-premises server, the server won't be reachable via the Azure ExpressRoute circuit if the corresponding connection fails.
 > * Terminating Azure ExpressRoute BGP connections on stateful devices can cause failover issues during planned or unplanned maintenance by Microsoft or your Azure ExpressRoute Provider. Test your setup to ensure proper failover, and when possible, terminate BGP sessions on stateless devices.
 
 ## Fine-tuning features for private peering
@@ -76,27 +75,14 @@ This section reviews optional features that help improve the high availability o
 
 ### Availability Zone aware Azure ExpressRoute virtual network gateways
 
-An Availability Zone in an Azure region combines a fault domain and an update domain. To achieve the highest resiliency and availability, configure a zone-redundant Azure ExpressRoute virtual network gateway. For more information, see [About zone-redundant virtual network gateways in Azure Availability Zones][zone redundant vgw]. To configure a zone-redundant virtual network gateway, see [Create a zone-redundant virtual network gateway in Azure Availability Zones][conf zone redundant vgw].
+An Availability Zone in an Azure region combines a fault domain and an update domain. To achieve the highest resiliency and availability, configure a zone-redundant Azure ExpressRoute virtual network gateway. For more information, see [About zone-redundant virtual network gateways in Azure Availability Zones](../vpn-gateway/about-zone-redundant-vnet-gateways.md). To configure a zone-redundant virtual network gateway, see [Create a zone-redundant virtual network gateway in Azure Availability Zones](../vpn-gateway/create-zone-redundant-vnet-gateway.md).
 
 ### Improving failure detection time
 
-Azure ExpressRoute supports BFD over private peering, reducing failure detection time over the Layer 2 network between Microsoft Enterprise Edge (MSEEs) and their BGP neighbors on the on-premises side from about 3 minutes (default) to less than a second. Quick failure detection helps hasten recovery. For more information, see [Configure BFD over Azure ExpressRoute][BFD].
+Azure ExpressRoute supports BFD over private peering, reducing failure detection time over the Layer 2 network between Microsoft Enterprise Edge (MSEEs) and their BGP neighbors on the on-premises side from about 3 minutes (default) to less than a second. Quick failure detection helps hasten recovery. For more information, see [Configure BFD over Azure ExpressRoute](./expressroute-bfd.md).
 
 ## Next steps
 
 This article discussed designing for high availability of an Azure ExpressRoute circuit. An Azure ExpressRoute circuit peering point is pinned to a geographical location and can be affected by catastrophic failures impacting the entire location.
 
-For design considerations to build geo-redundant network connectivity to the Microsoft backbone that can withstand catastrophic failures affecting an entire region, see [Designing for disaster recovery with Azure ExpressRoute private peering][DR].
-
-<!--Image References-->
-[1]: ./media/designing-for-high-availability-with-expressroute/exr-reco.png "Recommended way to connect using ExpressRoute"
-[2]: ./media/designing-for-high-availability-with-expressroute/suboptimal-lastmile-connectivity.png "Suboptimal last mile connectivity"
-[3]: ./media/designing-for-high-availability-with-expressroute/nat-options.png "NAT options"
-
-
-<!--Link References-->
-[zone redundant vgw]: ../vpn-gateway/about-zone-redundant-vnet-gateways.md
-[conf zone redundant vgw]: ../vpn-gateway/create-zone-redundant-vnet-gateway.md
-[Configure Global Reach]: ./expressroute-howto-set-global-reach.md
-[BFD]: ./expressroute-bfd.md
-[DR]: ./designing-for-disaster-recovery-with-expressroute-privatepeering.md
+For design considerations to build geo-redundant network connectivity to the Microsoft backbone that can withstand catastrophic failures affecting an entire region, see [Designing for disaster recovery with Azure ExpressRoute private peering](./designing-for-disaster-recovery-with-expressroute-privatepeering.md).