The TIA/EIA 568 standard divides the LAN cabling distribution system into the following sections:
- Work Area: Consists of the communication outlets (wall boxes and faceplates), wiring, and connectors needed to connect network hosts using the horizontal wiring subsystem to the telecommunication closet. The standard requires that two outlets be provided at each wall plate-one for voice and one for data.
- Horizontal Cabling: The cabling run from each outlet to the equipment room. The maximum horizontal distance is 90 meters (295 feet) independent of media type. An additional 6 meters (20 feet) is allowed for patch cables at the telecommunication closet and at the workstation, but the combined length cannot exceed 10 meters (33 feet).
- Telecommunication Rooms: Sometimes referred to as wiring closet, it provides an end point for horizontal cabling and backbone cabling. Typically contains patch panels and infrastructure devices such as switches and routers. Multiple telecommunication rooms exist in large organizations and connect to a central equipment room using backbone cabling.
- Backbone Cabling: The backbone wiring runs up through the floors of the building (risers) or across a campus and provides the interconnection between the equipment room and telecommunication closets. The distance limitations of this cabling depend on the type of cable and facilities it connects but the cabling consists of optical fiber cables.
- Central Equipment Room: Sometimes referred to as the network operation center (NOC). This room provides the endpoint for all backbone cabling and may contain enterprise class switches, routers, firewall appliances, servers, and access to the provider entrance facility.
- Entrance Facilities: This contains the service provider telecommunication service entrance to the building. This facility may also contain campus-wide backbone connections. This area also defines the network demarcation point, which is the interconnection to the local exchange carrier's telecommunication facilities. The demarcation point forms the boundary between the part of the network which is the responsibility of the organization and the part of the network which is the responsibility of the carrier.
Some of these LAN cabling distribution sections are shown in the figure.