I think the OP is referring to a set of parameters to use in the ETL / Integration process, i regularly use a database table with Param Name and Param value (possibly more depending on requirements), then read the values using ODI Variables, update the values using ODI Proceedures etc.
Holding things like : SMTP server, ETL Date, SCN Number, email address etc. - All things that would be specific to the environment that you dont want to hard code.
Just create the table in the DB, reverse engineer it into a model then reference the table using the Substituion method e.g : Select param_value from <%=odiRef.getObjectName( "DW_ETL_PARAMETERS" )%> where param_name = 'xyz'
or update <%=odiRef.getObjectName( "DW_ETL_PARAMETERS" )%> set param_value = xyz where param_name = abc;
Is that what you mean?
Its not that common in ODI to be honest given the Master / Work Repository setup but if you must you can use Variables in Topology for your connections :