Image shows a PBX and Voicemail & Fax Server, located in San Francisco, communicating with the Infrastructure tier. The Infrastructure tier consists of the Oracle Collaboration Suite Database and Oracle Internet Directory. A second Voicemail & Fax Server is shown on a shaded background indicating that this is a new server. There is a dotted line connecting the new server to the same PBX, and there is a dotted line connecting it to the Infrastructure tier. tier