25 July 2008

Structured Cabling System

Back in the old days of networking newbie, I didn't even care about networking. What's so interesting about it. Just a bunch of cables connected from the computers to switches or routers/modems voila you get internet.

Few years later, come to my notice that networking is far far more interesting than I had imagined. By the way this story is going somewhere if you wonder.

Networking (in physical) is more than I said before, there are lots of in between the things I mentioned. Switches and routers should be enough for home or SOHO usage, but when it comes to enterprise, lots of new networking "creatures" would pop-out.

All these creatures combined and managed well can be called Structured Cabling System (SCS).

What SCS basically means is the systematic ways or you can say standards for network cabling and telecommunication rooms. These standards issued by the Telecommunications Industry Association (TIA) and the Electronic Industries Alliance (EIA), and other standards organization.

Typically you can see telecommunication rooms in a building divided into three main parts:

1. MDF (Main Distribution Frame) or can also be called MC (Main Cross-connect)

MDF is where all of the backbone cables gather, there should be usually 1 MDF in a building, you can see the picture one of the rack used in an MDF.

This is where the big kick ass routers and core switches located. There are also 110 blocks/66 blocks use for UTP cables connectivity for data or voice (phone). Yes, you can also use UTP cables for phones. In fact, you can use them to connect about anything, computers, telephones, speaker attenuators (controllers), alarms, etc. What UTP cable we usually use, 4 pairs? guess what they also produce 25 paris or more (up to 500 pairs), which means in one cable you can have 25 or more pairs of cables!!! heavy, I'm telling you.

In MDF, if you use fiber optics for backbone, you should have Fiber Distribution Frame.

From MDF, you connect to a Demarcation Point, used for connectivity to the outside world, this is where the line ends between your responsibility as a network engineer with the service provider.

2. IDF (Intermediate Distribution Frame) or IC (Intermediate Cross-connect)

Usually you would have one or more IDF in each floor in a building. Here the connection from the MDF terminated, or should I say where the backbone cables end. Then from IDF you would connect to the end users.

The IDF is more or less similar to the MDF, but with a smaller scale, only about a couple of meters square room.

This is where the smaller switches located, then you connect the patch cables from the switch to patch panels or 110/66 blocks. Patch panels and 110/66 blocks are equipments where you terminate the cables. Then from the patch panels you connect cables directly to the work area of end users.

3. Work Area

Now this is where the cables end, this is whre the place where end users located. The end users shouldn't care about how complicate the cables that connect their computers to the network.

The cables from the IDF are spread to the modular jack wall plates, you can use UTP cables or even fiber optics.

This is just a scratch on the surface of networking world, it may seems complicated but believe me, if you are in to it, it should not be that hard.