Federation is basically having 2 (or more) DB look like they are one. Applications only connect to one DB and can access the others through normal SQL. The tables in the other DBs are given "nicknames" and that is how the data is accessed. Look in the online reference at: http://publib.boulder.ibm.com/infoce.../v8//index.jsp
and look in Administring and you will find the Federation documentation.