The Rational Performance Test Server is the server to generate load for the load- and stress tests created with RTW and RPT.
More info see here
Note! This server has only the load generation capability, not the hosting of test virtualizations.
Which mode to use for an agent? PVU mode means that this usage is covered by a valid PVU-license. This administration only.
Agent mode means that a token-license is obtained from a license server hosting token-licenses.