Tier 2: Application servers
The next layer of a three tier architecture is the application layer. Using www.dell.com as an example, after you have looked at all of the system information, spec sheets, etc. and you click "Configure & Price," you begin to interact with an Microsoft® Commerce Server running on the middle-tier application server. Choose from the Dell line of versatile PowerEdgeTM general-purpose servers and PowerVaultTM storage solutions along with an extremely broad base of hardware, O/S and application support to build the core of your infrastructure.