Conceptually Tableau Architecture contains the following components:
Client or Source Data : OLTP, OLAP, Files, Multidimensional Data and others
Data Connectors : Tableau Fast Data Engine, SQL Connectors, MDX Connectors and Repository
Main components : Data Server, VizQL (Vizual Query Language) Server and Application Server
Gateway : Gateway and Load Balancer
Users or Clients : Desktop Clients, Mobile Clients and Web Users