Cable Management
Lesson overview.
In this lesson, we will cover:
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Cable distribution.
Cable management techniques and components.
Cable distribution.
When designing a network, some thought must go into how the cable runs will be organized and
distributed. Part of this cable distribution design will involve some common components and
concepts. The most important of these are outlined below.
Main distribution frame (MDF).
The main distribution frame (MDF) is the point where outside traffic enters a location and is then
distributed to the internal network. The MDF is where the demarc, demarc extension, main
switch, or router and patch panel are placed.
Highlights:
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The MDF is where outside traffic enters a location and then is distributed to the internal
network.
The MDF is the location where the demarc, demarc extension, main switch/router, and
patch panel are placed.
Intermediate distribution frame (IDF).
An intermediate distribution frame (IDF) is a location’s solution when a single MDF is not
sufficient. IDFs usually occur in multistory buildings. They are connected to the MDF by vertical
cross-connect (VCC) cables. It is common for an MDF to contain separate IDF panels for each
floor of a building.
Highlights:
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An IDF is a location’s solution when a single MDF is not sufficient.
IDFs are connected to the MDF by VCC cables.
It is common for an MDF to contain separate IDF panels for each floor of a building.
VCC (vertical cross-connect).
A VCC is the main patch panel for a location. In most installations, a VCC usually resides in the
same location as (or very close to) the demarc and main switch or router.
Highlights:
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A VCC is the main patch panel for a location.
It usually resides in the same location as the demarc and main switch/router.
Patch panel.
Patch panels are used to terminate network cable runs, usually within a building, such as from
the wall jacks to a central location. The network runs are called horizontal cabling. Patch panels
are used to organize and administer the physical aspects of the network cables. Network runs
are punched down to the back of the patch panel, which normally contains either a 66 or a 110
block, with an associated port on the front of the patch panel. Patch cables are used to connect
the patch panel ports to networking gear, quite often a switch.
Workstations connect to the patch panel using horizontal cabling. This location is called the
horizontal cross-connect (HCC) and is usually located in the IDF. Switches may or may not be
present in this location. If a workstation needs to be relocated to a different switch or port, all
that needs to be done is to make the change in the location of the patch panel. A technician can
unplug the cable from one port and plug it into a new port.
Highlights:
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A patch panel is used to terminate network cable runs (horizontal cabling), usually within
a building.
Network runs are punched down to the back of a patch panel with an associated port on
the front of the patch panel.
Patch cables are used to connect the patch panel ports to networking gear.
Workstations connect to a patch panel using horizontal cabling; this location is called the
HCC and is usually located in the IDF.
Cable management techniques and components.
When it comes to managing and organizing cables, there are a number of techniques and
components that will make the task easier. The two most important of these are outlined below.
Labeling.
Labeling is an important part of cable management. It can cause stress when working with
networks, but it doesn’t have to. The key to proper labeling is to create a naming convention (a
systematic and consistent method) that makes sense for the particular situation. Proper labeling
will ease the management of the physical aspects of the network, especially when dealing with
cables.
Labels should be placed on everything that is associated with the network—beginning from the
wall jacks all the way through the patch panels, switches, and routers. The naming convention
should be documented and kept with the network diagrams. It is important to be consistent and
to document everything. An example of this is provided below.
Naming convention example:
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Office 219 has network outlets (jacks) on all four walls.
○ Jacks could be labeled 219N (North), 219W (West), etc.
The horizontal cabling from 219 feeds into a patch panel in an IDF located on the
second floor that contains two 48-port switches that tie in all of the HCCs.
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○ The switches could be labeled SW2A and SW2B.
○ The cables coming from 219 could be labeled 219W, 219S, etc.
The patch cables for office 219 connect to SW2B’s ports 20-24.
○ The patch cables could be labeled 219N-SW2B-21 or 219E-SW2B-22, etc.
Cable trays.
Large masses of cables can block airflow and act as an insulator that allows for excessive heat
to build up. Cable trays are often used to organize cabling and to keep it away from areas where
it may cause heat to build up. Cable trays keep bundles of cables neat and fairly well organized.
The trays are helpful in routing cable runs away from areas where the cables could potentially
be damaged.
Highlights:
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Masses of cables can block airflow and act as an insulator, allowing excessive heat to
build up.
Cable trays are used to organize cabling, to keep cabling away from areas where it may
cause heat buildup, and to route it away from areas where cables could be damaged.
What was covered.
Cable distribution.
The MDF is where outside network traffic enters a location and gets distributed to the internal
network. In multistory buildings, it is common for there to be IDFs. Horizontal cables connect
workstations to patch panels in the IDF. VCC cables connect the IDF to the MDF. Patch panels
are where network cabling runs are terminated.
Cable management techniques and components.
Labeling is an important part of any cable management system that gets developed. A key part
of labeling is to devise a naming convention that makes sense for the situation and to be
consistent in utilizing it. Everything dealing with the network should be labeled and documented.
Cable trays are used to manage cables and to keep them from creating a heat problem or being
damaged.