MDF and IDF – CompTIA Network+ N10-006 – 5.7

Your main and intermediate distribution frames are the foundation of your network. In this video, you’ll learn how these distribution frames are structured and what resources are commonly found in an MDF and IDF.
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If you work in a relatively large environment, you’re going to work with a distribution frame. This is where there is a passive cable termination, so this is not a powered system. You’re instead terminating cables using a punch down block or a patch panel. These are usually located in the back of the data center or across a very large wall because you need a lot of real estate to be able to punch down that many different cable connections.

And this may not be just for copper. You might have fiber connections. There may be both voice and video and data all combined on the same punch down block area back in the distribution frame. You often use this as the name of a room or a location. This is a very significant part of the network, because you have all of the data for all of your systems passing through this distribution frame.

The central point of the network is usually the main distribution frame or the MDF. This is usually in your data center itself, and it’s where you’re terminating WAN connections. It’s where all of your network connections are terminating. If you need to go from the inside to the outside, you’re usually doing this at the MDF. That means it’s a good test point as well.

If you want to determine where you might see errors occurring on the network, you can go to the MDF to have both access to the internal network and the external network as well. As I mentioned before, it’s often in the center of the network. It is in the middle of the data center. If you want to find the MDF, you’re probably also going to find the data center at the same time.

The other distribution frame you’ll usually find is the intermediate distribution frame or the IDF. This is an extension of the MDF. You can think of it as an auxiliary of the MDF, and it is a place where you’re able to bring your users and connect them into the main network. There are going to be uplinks from here to the MDF.

This is where you usually have switches for a floor or workgroup. There’ll be local resources or anything else that doesn’t need to be in the center of the network. You will commonly see IDFs in medium- to large-scale environments where you have users on different floors or in different buildings, and they’re usually separated by geography.

Here’s a very simple diagram that helps to explain the differences between in MDF and an IDF. You can see in this MDF display is the internet connection and any other WAN connections that might be coming into the main part of the network. Your file servers, your web servers, and all of your centralized equipment is usually located at this MDF location.

Then you have the IDFs. These are the devices out on the floors. They may be in different buildings, but they are connected back to the MDF through a series of uplinks, and the IDF are your local resources. This is usually where your users will be connecting to an IDF switch, which is thing connecting back to the MDF to a core switch.