This illustration shows a typical installation layout for Microsoft Transaction Server with multiple Oracle databases. There are three tiers.

Tier 1 consists of local area network (LAN)-based client connections and Internet browser (through HTTP) client connections. These clients connect to the Microsoft Transaction Server application.

Tier 2 consists of the Microsoft Transaction Server application running on a Windows NT/2000 host computer. The Oracle Services for Microsoft Transaction Server and Oracle MTS Recovery Service are installed on this computer.

Tier 3 consists of the Oracle databases to which to connect.