Answer:
MDF, IDFs
Explanation:
MDF or main distribution frame is a cable racking system in networking used to interconnect and manage information technology connecting cables from itself to multiple IDFs.
The IDF or intermediate distribution frame, on the other hand, are cable racks that holds or stacks networking devices together and connects it cables to a central MDF rack.
A scenario of this connection is IDFs mounted on various floors on a building and all connected to one MDF.