title: "SignalR Scaleout with Azure Service Bus | Microsoft Docs"
author: MikeWasson
description: "Software versions used in this topic Visual Studio 2013 .NET 4.5 SignalR version 2 Previous versions of this topic For the SignalR 1.x version of this topic,..."
In this tutorial, you will deploy a SignalR application to a Windows Azure Web Role, using the Service Bus backplane to distribute messages to each role instance. (You can also use the Service Bus backplane with [web apps in Azure App Service](https://docs.microsoft.com/azure/app-service-web/).)
- The [Windows Azure SDK](https://go.microsoft.com/fwlink/?linkid=254364&clcid=0x409).
- Visual Studio 2012 or 2013.
The service bus backplane is also compatible with [Service Bus for Windows Server](https://msdn.microsoft.com/en-us/library/windowsazure/dn282144.aspx), version 1.1. However, it is not compatible with version 1.0 of Service Bus for Windows Server.
The Service Bus backplane uses topics to send messages. For the latest pricing information, see [Service Bus](https://azure.microsoft.com/pricing/details/service-bus/). At the time of this writing, you can send 1,000,000 messages per month for less than $1. The backplane sends a service bus message for each invocation of a SignalR hub method. There are also some control messages for connections, disconnections, joining or leaving groups, and so forth. In most applications, the majority of the message traffic will be hub method invocations.
This code configures the backplane with the default values for [TopicCount](https://msdn.microsoft.com/en-us/library/microsoft.aspnet.signalr.servicebusscaleoutconfiguration.topiccount(v=vs.118).aspx) and [MaxQueueLength](https://msdn.microsoft.com/en-us/library/microsoft.aspnet.signalr.messaging.scaleoutconfiguration.maxqueuelength(v=vs.118).aspx). For information on changing these values, see [SignalR Performance: Scaleout Metrics](signalr-performance.md#scaleout_metrics).
Create a Cloud Service, as described in [How to Create and Deploy a Cloud Service](https://docs.microsoft.com/azure/cloud-services/cloud-services-how-to-create-deploy). Follow the steps in the section "How to: Create a cloud service using Quick Create". For this tutorial, you do not need to upload a certificate.
Create a new Service Bus namespace, as described in [How to Use Service Bus Topics/Subscriptions](https://docs.microsoft.com/azure/service-bus-messaging/service-bus-dotnet-how-to-use-topics-subscriptions). Follow the steps in the section "Create a Service Namespace".
> Make sure to select the same region for the cloud service and the Service Bus namespace.
## Create the Visual Studio Project
Start Visual Studio. From the **File** menu, click **New Project**.
In the **New Project** dialog box, expand **Visual C#**. Under **Installed Templates**, select **Cloud** and then select **Windows Azure Cloud Service**. Keep the default .NET Framework 4.5. Name the application ChatService and click **OK**.
- ChatService: This project is the Windows Azure application. It defines the Azure roles and other configuration options.
- SignalRChat: This project is your ASP.NET MVC 5 project.
## Create the SignalR Chat Application
To create the chat application, follow the steps in the tutorial [Getting Started with SignalR and MVC 5](../getting-started/tutorial-getting-started-with-signalr-and-mvc.md).
Use NuGet to install the required libraries. From the **Tools** menu, select **Library Package Manager**, then select **Package Manager Console**. In the **Package Manager Console** window, enter the following commands:
Now you need to get your service bus connection string. In the Azure portal, select the service bus namespace that you created and click the Access Key icon.
Right-click the SignalRChat role and select **Properties**. Select the **Configuration** tab. Under **Instances** select 2. You can also set the VM size to **Extra Small**.
If this is your first time publishing to Windows Azure, you must download your credentials. In the **Publish** wizard, click "Sign in to download credentials". This will prompt you to sign into the Windows Azure portal and download a publish settings file.
Click **Publish**. It can take a few minutes to deploy the application and start the VMs.
Now when you run the chat application, the role instances communicate through Azure Service Bus, using a Service Bus topic. A topic is a message queue that allows multiple subscribers.
The backplane automatically creates the topic and the subscriptions. To see the subscriptions and message activity, open the Azure portal, select the Service Bus namespace, and click on "Topics".
This error can occur if the transaction level for an operation is set to something other than `Serializable`. Verify that no operations are being performed with other transaction levels.
