Merge pull request #107541 from mikebudzynski/apim-vnet-scale

APIM: mention scaling in VNET

Author: PRMerger13

articles/api-management/api-management-using-with-vnet.md

@@ -175,10 +175,12 @@ When an API Management service instance is hosted in a VNET, the ports in the fo
 ## <a name="subnet-size"> </a> Subnet Size Requirement
 Azure reserves some IP addresses within each subnet, and these addresses can't be used. The first and last IP addresses of the subnets are reserved for protocol conformance, along with three more addresses used for Azure services. For more information, see [Are there any restrictions on using IP addresses within these subnets?](../virtual-network/virtual-networks-faq.md#are-there-any-restrictions-on-using-ip-addresses-within-these-subnets)
 
-In addition to the IP addresses used by the Azure VNET infrastructure, each Api Management instance in the subnet uses two IP addresses per unit of Premium SKU or one IP address for the Developer SKU. Each instance reserves an additional IP address for the external load balancer. When deploying into Internal vnet, it requires an additional IP address for the internal load balancer.
+In addition to the IP addresses used by the Azure VNET infrastructure, each Api Management instance in the subnet uses two IP addresses per unit of Premium SKU or one IP address for the Developer SKU. Each instance reserves an additional IP address for the external load balancer. When deploying into Internal virtual network, it requires an additional IP address for the internal load balancer.
 
 Given the calculation above the minimum size of the subnet, in which API Management can be deployed is /29 that gives three usable IP addresses.
 
+Each additional scale unit of API Management requires two more IP addresses.
+
 ## <a name="routing"> </a> Routing
 + A load balanced public IP address (VIP) will be reserved to provide access to all service endpoints.
 + An IP address from a subnet IP range (DIP) will be used to access resources within the vnet and a public IP address (VIP) will be used to access resources outside the vnet.