Resolution: TRDP is the default if you are using the default Silent Install file (TIBCOUniversalInstaller-rv.silent). You could run the installer using the following command line with your own silent file:
TIBCOUniversalInstaller -silent -V responseFile="myFile.silent"
and specify the protocol in your silent install file in the following entry:
<entry key="protocolDaemon">trdp</entry>