Merge pull request #272038 from anavinahar/patch-278

Update load-balancer-floating-ip.md

Author: prmerger-automator[bot]

articles/load-balancer/load-balancer-floating-ip.md

@@ -5,7 +5,7 @@ services: load-balancer
 author: mbender-ms
 ms.service: load-balancer
 ms.topic: how-to
-ms.date: 02/28/2023
+ms.date: 04/12/2024
 ms.author: mbender
 ms.custom: template-how-to, engagement-fy23
 ---
@@ -32,6 +32,41 @@ In the diagrams, you see how IP address mapping works before and after enabling
 
 You configure Floating IP on a Load Balancer rule via the Azure portal, REST API, CLI, PowerShell, or other client. In addition to the rule configuration, you must also configure your virtual machine's Guest OS in order to use Floating IP.
 
+:::image type="content" source="media/load-balancer-multivip-overview/load-balancer-multivip-dsr.png" alt-text="Diagram of load balancer traffic for multiple frontend IPs with floating IP.":::
+
+For this scenario, every VM in the backend pool has three network interfaces:
+
+* Backend IP: a Virtual NIC associated with the VM (IP configuration of Azure's NIC resource).
+* Frontend 1 (FIP1): a loopback interface within guest OS that is configured with IP address of FIP1.
+* Frontend 2 (FIP2): a loopback interface within guest OS that is configured with IP address of FIP2.
+
+Let's assume the same frontend configuration as in the previous scenario:
+
+| Frontend | IP address | protocol | port |
+| --- | --- | --- | --- |
+| ![green frontend](./media/load-balancer-multivip-overview/load-balancer-rule-green.png) 1 |65.52.0.1 |TCP |80 |
+| ![purple frontend](./media/load-balancer-multivip-overview/load-balancer-rule-purple.png) 2 |*65.52.0.2* |TCP |80 |
+
+We define two floating IP rules:
+
+| Rule | Frontend | Map to backend pool |
+| --- | --- | --- |
+| 1 |![green rule](./media/load-balancer-multivip-overview/load-balancer-rule-green.png) FIP1:80 |![green backend](./media/load-balancer-multivip-overview/load-balancer-rule-green.png) FIP1:80 (in VM1 and VM2) |
+| 2 |![purple rule](./media/load-balancer-multivip-overview/load-balancer-rule-purple.png) FIP2:80 |![purple backend](./media/load-balancer-multivip-overview/load-balancer-rule-purple.png) FIP2:80 (in VM1 and VM2) |
+
+The following table shows the complete mapping in the load balancer:
+
+| Rule | Frontend IP address | protocol | port | Destination | port |
+| --- | --- | --- | --- | --- | --- |
+| ![green rule](./media/load-balancer-multivip-overview/load-balancer-rule-green.png) 1 |65.52.0.1 |TCP |80 |same as frontend (65.52.0.1) |same as frontend (80) |
+| ![purple rule](./media/load-balancer-multivip-overview/load-balancer-rule-purple.png) 2 |65.52.0.2 |TCP |80 |same as frontend (65.52.0.2) |same as frontend (80) |
+
+The destination of the inbound flow is now the frontend IP address on the loopback interface in the VM. Each rule must produce a flow with a unique combination of destination IP address and destination port. Port reuse is possible on the same VM by varying the destination IP address to the frontend IP address of the flow. Your service is exposed to the load balancer by binding it to the frontend’s IP address and port of the respective loopback interface. 
+
+You notice the destination port doesn't change in the example. In floating IP scenarios, Azure Load Balancer also supports defining a load balancing rule to change the backend destination port and to make it different from the frontend destination port.
+
+The Floating IP rule type is the foundation of several load balancer configuration patterns. One example that is currently available is the [Configure one or more Always On availability group listeners](/azure/azure-sql/virtual-machines/windows/availability-group-listener-powershell-configure) configuration. Over time, we'll document more of these scenarios. For more detailed information on the specific Guest OS configurations required to enable Floating IP, please refer to [Azure Load Balancer Floating IP configuration](load-balancer-floating-ip.md) in the next section.
+
 ## Floating IP Guest OS configuration
 
 In order to function, you configure the Guest OS for the virtual machine to receive all traffic bound for the frontend IP and port of the load balancer. Configuring the VM requires: