Structured Cabling Design for Large Buildings

Structured Cabling in Multi-Story Buildings

The layout is somewhat complex when covering large areas, such as multi-story buildings. In this sense, we must consider the design constraints imposed by the Local Area Network (LAN) technology you wish to implement:

• Network traffic segmentation.
• Maximum length of each network segment.
• Presence of electromagnetic interference.
• Need for Virtual Local Area Networks (VLANs).
• Etc.

Apart from these constraints, the concept of structured cabling is simple:

• Route cables on each floor.
• Interconnect cables from each floor.

Horizontal Cabling: Floor Distribution System

All cables are concentrated in the **floor distribution cabinet** (also known as a **telecommunications closet**). This cabinet serves as a frame where electrical connections (or "joints") are made between cables. Depending on the network design requirements, this can be an active or passive communications element, such as a hub or a switch. In any case, this cabinet concentrates all cables from the same floor. This subsystem includes all transmission media (e.g., cables, fiber optics, coaxial) connecting the distribution points on the floor with the workstation connectors. This is one of the most critical aspects of the design, as it dictates the distribution of network access points on the floor, which differs significantly from a conventional network setup.

Vertical Cabling: Trunk and Backbone Systems

Next, all floor distribution cabinets must be interconnected with another set of cables that run vertically through the building, floor by floor. This is typically achieved using existing conduits within the building. If existing conduits are insufficient, it may be necessary to install new ones, utilize existing openings (e.g., elevator shafts or stairwells), or, less ideally, use the building's facade. In cases where the floor cabinet already contains network electronics, the vertical wiring serves as the network backbone. Note that this aggregates the bandwidth from all floors. Therefore, a higher-capacity technology, such as FDDI or Gigabit Ethernet, is often employed.

Main Equipment Room and Service Entry Point

Vertical cabling terminates in a central room where all cables from the building converge. This room houses the primary network electronics and other telecommunications infrastructure, including bridges, gateways, firewalls, telephone systems, cable TV or satellite reception, and potentially the main data processing center (if applicable).