Understanding the difference between Blocks and Parts (and thus the difference between BDDs and IBDs) is a massively important topic for a SysML practitioner and something that very few Rhapsody users with no training will guess their way into (I'm forever finding users who try to draw connectors between Blocks, give up, and choose to use Flows instead!).
The whole Block, Part, Port/Connector capability of SysML (and to some extent UML) is really powerful though. This video tries to shed some light on the typical question: Why can't I draw a connector between ports on two Blocks? The video is using IBM Rational Rhapsody 8.2.1 (released June 2017)
p.s. The topic of which ports to use is a whole different ballgame ;-)