# Practical Networking

Some notes on the theory of practical installations (yes, the irony isn't lost on me.)


## Solid vs Stranded Core UTP
In solid core UTP, each wire has a single copper core.
This increases conductivity but is more likely to fail completely when the core breaks.
This happens becasue the solid core is less flexible than stranded core.


## Horizontal Run
A length of cable that runs from the server room to the endpoints.
These are usually the arms in the star topology.
These are usually solid core UTP.
The run distance is limited to 90m.


## Patch cables
Thsee are used at either end of the run cable.
The more flexible stranded core UTP is used here.
This is because the ends are usually moved quite frequently.
E.g. when a new computer is plugged into the network or the network switch ports are changed.
Patch cable length is limited to 10m.


## Demarcation, AKA Demarc
The point where a building's network ends and the internet begins.
Usually a Network Interface Unit (NIU) is placed here.
These are also called Network Interface Boxes (NIB) or a Network Interface Device (NID).


## Distribution Frames
A room (or cabinet, box, etc) that houses the network devices (except for runs and hosts.)
There are two types of distribution frames:

### Main Distribution Frame
This is the room that contains the Demarc

### Intermediate Distribution Frame
Contains all the networking infrastructure for a floor.

A main and intermediate distribution frame might be the same room or cabinet.
For instance, on the ground floor of an office, or if an office only has one floor.

## Patch Panel
The patch panel serves as a phyiscally static point where runs can terminate in the server room.
They come in two sizes, 66 Block and 100 Block.
Each wire in a run is physically locked into a the block, which is linked to a female RJ-45 port.
This allows the patch cable to be connected to a run without moving the run.
The run is locked in using a punchdown tool.