Merge pull request #205230 from dlepow/ipfix

[APIM] Consolidated IP address guidance

Author: PRMerger9

articles/api-management/api-management-howto-ip-addresses.md

@@ -98,12 +98,14 @@ For traffic restriction purposes, you can use the range of IP addresses of Azure
 
 ## Changes to the IP addresses
 
-In the Developer, Basic, Standard, and Premium tiers of API Management, the public IP addresses (VIP) and private VIP addresses (if configured in the internal VNet mode) are static for the lifetime of a service, with the following exceptions:
+In the Developer, Basic, Standard, and Premium tiers of API Management, the public IP address or addresses (VIP) and private VIP addresses (if configured in the internal VNet mode) are static for the lifetime of a service, with the following exceptions:
 
-* The service is deleted and then re-created.
+* The API Management service is deleted and then re-created.
 * The service subscription is [suspended](https://github.com/Azure/azure-resource-manager-rpc/blob/master/v1.0/subscription-lifecycle-api-reference.md#subscription-states) or [warned](https://github.com/Azure/azure-resource-manager-rpc/blob/master/v1.0/subscription-lifecycle-api-reference.md#subscription-states) (for example, for nonpayment) and then reinstated.
-* Azure Virtual Network is added to or removed from the service.
-* API Management service is switched between External and Internal VNet deployment mode.
-* [Availability zones](../availability-zones/migrate-api-mgt.md) are enabled, added, or removed.
+* (Developer and Premium tiers) Azure Virtual Network is added to or removed from the service.
+* (Developer and Premium tiers) API Management service is switched between external and internal VNet deployment mode.
+* (Premium tier) [Availability zones](../availability-zones/migrate-api-mgt.md) are enabled, added, or removed.
+* (Premium tier) In [multi-regional deployments](api-management-howto-deploy-multi-region.md), the regional IP address changes if a region is vacated and then reinstated.
 
-In [multi-regional deployments](api-management-howto-deploy-multi-region.md), the regional IP address changes if a region is vacated and then reinstated.
+    > [!IMPORTANT]
+    > When changing from an external to internal virtual network (or vice versa), changing subnets in the network, or updating availability zones for the API Management instance, you must configure a different [public IP address](api-management-using-with-vnet.md?tabs=stv2#prerequisites) resource than the one configured previously. You may swap back to the original IP address if needed.

includes/api-management-virtual-network-prerequisites.md

@@ -25,7 +25,11 @@ Some prerequisites differ depending on the version (`stv2` or `stv1`) of the [co
 
   * The IP address must be in the same region and subscription as the API Management instance and the virtual network.
 
-  * When creating a public IP resource, ensure you assign a **DNS name label** to it. The label you choose to use does not matter but a label is required if this resource will be assigned to an API Management service.
+  * When creating a public IP address resource, ensure you assign a **DNS name label** to it. The label you choose to use does not matter but a label is required if this resource will be assigned to an API Management service.
+
+  * For best network performance, it's recommended to use the default **Routing preference**: **Microsoft network**.  
+
+  * When creating a public IP address in a region where you plan to enable [zone redundancy](../articles/availability-zones/migrate-api-mgt.md) for your API Management instance, configure the **Zone-redundant** setting.
 
   * The value of the IP address is assigned as the virtual public IPv4 address of the API Management instance in that region.