Relationship between administrative law and constitutional law?

Great question, and one that people need to actually be made aware of!

Administrative law allows for AGENCY's to perform and hold their own 'hearings'.

There are times when unless you ask, or even know to ask, that you might not be able to tell the difference. Of course there are even times when even if you do ask, you may not get the answer. Suggestion: Research Administrative Procedure Act, followed by different agency's policy's in which you could be subject to.