From a conceptual standpoint EASA is a 'Three-Tier' architecture, detailed below:

1. Client computers:
   • Web Browser Client
   • Excel Desktop Client
2. An EASA Server
3. Compute Servers, database servers, and Excel Servers

Illustrated below is a typical layout of EASA’s Three-Tier Architecture.

An EASA Server is the central machine in an EASA system.

An EASA Server:

• Serves HTML as a web server
• Serves files as a file server
• Communicates with Users via web browsers
• Stores the Application Library and Results Library
• Maintains a queue of submitted runs
• Submits processes to Compute Servers
• Reads-from and writes-to Database Servers
• Contains EASAP Server functionality to serve EASAP's directly to the browser
  • In some cases EASAP Server functionality may be delegated to a Compute Server
  • In many cases an Excel Server will be combined with EASAP Server functionality (EASAP/Compute Server)

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

Client computers are the end Users’ desktops and mobile devices who connect via web browser to the EASA Server via a network (LAN, WAN, VPN) connection.

In EASA 6.0, the Excel Desktop Client is available as an agile alternative to the browser interface though Excel must be installed prior. The EASA Ribbon will install automatically the first time an Excel Client EASAP is Tested by an Author or Published and then run by a User.

A Compute Server is a machine that runs the underlying 'batch' application being driven by an EASAP. Most likely this machine will be a computer that already runs the software application in an organization. However, as EASA opens up an existing software application to a larger number of Users, it can create a new computational demand within an organization and therefore potentially produce a need for more Compute Servers.

For more information on how to configure Compute Servers, see Configuring Compute Servers.

An Excel Server is a specialized Compute Server dedicated to hosting the 'live' or running Microsoft® Excel spreadsheets that interact with an EASAP.

EASA may be configured to communicate with a database either local to an EASA Server or on a remote computer. Thus EASA can use well-known commercial database technologies such as:

• SQL Server
• Oracle
• MySQL
• Sybase

By extension EASA may interface with database applications such as:

• ERP
• CRM
• PDM
• PLM

For configuration details see Configuring Connections to External Databases.