The installed layout of EASA can be classified as a Three-Tier Architecture, in which the client computers are Tier 1, the EASA Server is Tier 2 and the Compute Servers, database servers and Excel Servers are Tier 3.

A typical layout of EASA’s Three-Tier Architecture is illustrated below.

The EASA Server is the computer on which the EASA software is installed. This computer will act as both a web server and a file server and will perform the following functions:

• Communicate with Users via web browsers
• Store both the Application Libraries and Results Libraries
• Run the queuing system
• Submit processes to Compute Servers
• Read and write data stored in databases on Database Servers

For more information on creating an EASA Server by installing EASA, see Installation of EASA Software.

Client computers are the end users’ desktops and mobile devices. These computers must be able to connect to the EASA Server via a network (LAN, WAN, VPN) connection and have loaded on them a web browser supported by EASA. In many instances, EASAPs can be authored to be web browser compatible. However, more complex applications may require that the EASA Client software be installed on the client computer to work properly.

The Compute Servers are the machines that will run the underlying software applications being driven by EASAPs. Most likely these machines will be the computers that already run these software applications within your organization today. However, since EASA will open up your existing software applications to a larger user base, it can greatly accelerate the rate of computing performed within your organization and therefore potentially produce a need for more computing power.

For more information on how to configure Compute Servers to be used by EASA, see the Configuring Compute Servers page.

A special type of Compute Server called an Excel Server is available in EASA. Excel Servers are dedicated to running Microsoft® Excel spreadsheets that are interacting with EASAPs. To be an Excel Server, a computer must be running Windows and have the 'Excel Server Web Service' software installed.

EASA can be configured to communicate with databases that are either local to the EASA Server or on remote computers. Therefore, EASA can interface with well-known commercial database technologies, such as SQL Server, Oracle, MySQL, Sybase, etc., and with database applications such as ERP, CRM, PDM and PLM software systems. For more information on how to configure EASA to communicate with database servers, see the Configuring Connections to External Databases page.