In Act 2 Scene 1, Of what is Iago successful at convincing Roderigo regarding Desdemona? What demands does he make of him regarding Cassio?

Iago knows that Roderigo has the hots for Desdemona. Iago convinces him that he can deliver Desdemona to him and that Desdemona will somehow be incredibly in love with him. I believe Iago wants Roderigo to get Cassio drunk and start an arguement with him.