Application Tier is an important part of the Team Foundation Server since it houses ASP.NET web services used to talk to Data Tier and Client Tier. It includes such components are:

• Source Control
• Work Item Tracking
• Event Notifications Engine
• Scheduler
• Team Build Service

There are several important applications that run on top of the Application Tier. They are:

• TFSAdminUtil
• TFSSecurity
• Command-Line Tools
• IIS
• ASP.NET
• WSS
• MS SQL Reporting Services

These applications require additional software to be installed before we actually deploy Application Tier. First, we need to install IIS in order to run IIS, ASP.NET. Secondly, we need to install SQL Server Reporting Service and then WSS. Only after we install all three applications we can proceed with our main TFS Application Tier installation. During our installation we may also apply .NET hot fixes hence enhancing performance of the Application Tier which runs on top of ASP.NET Framework.