MDF
Short for main distribution frame, a cable rack that interconnects and manages the telecommunications wiring between itself and any number of
IDFs. Unlike an IDF, which connects internal lines to the MDF, the MDF connects private or public lines coming into a building with the internal network. For example, an enterprise that encompasses a building with several floors may have one centralized MDF on the first floor and one IDF on each of the floors that is connected to the MDF
http://www.webopedia.com/TERM/M/MDF.html
data center is a term that refer to the entire physical location that host multiple physical and logical technologies such as MDF, Racks, servers , Network equipments ..etc where an MDF could be used to interconnect the building floors IDFs to the building Data center
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