Backbone cabling is the part of a structured cabling system that connects the main equipment room to the telecommunications rooms on each floor, and connects buildings on a campus. If horizontal cabling is the street to each desk, the backbone is the highway between floors and buildings. When the backbone is undersized or poorly documented, every user downstream feels it.
Where backbone cabling fits in structured cabling
A structured cabling system is usually described in six subsystems: entrance facilities, the equipment room, telecommunications rooms, backbone cabling, horizontal cabling and the work area. The backbone links the equipment room (often called the MDF) to each telecommunications room (IDF), and on a campus it runs between buildings. See our overview of structured cabling services for how the pieces fit together.
Two kinds of backbone
- Intra-building backbone runs vertically or horizontally inside one building, from the MDF to IDFs on other floors or wings.
- Inter-building (campus) backbone runs between buildings, through underground conduit or aerial pathways, connecting each building’s network to the core.
Fiber vs copper backbone
Most modern backbones are fiber. Multimode fiber (OM3, OM4) is common inside buildings and supports 10 Gb and higher over the distances found in most offices. Single-mode fiber (OS2) covers much longer distances and is the usual choice between buildings and for future higher speeds. Copper still has a role for voice tie cables and short backbone links, but it is limited by distance and bandwidth.
Planning backbone capacity
- Strand count: install more fiber strands than you need today. Pulling new fiber later through occupied risers costs far more than spare strands now.
- Redundancy: for critical sites, run diverse paths so a single cut does not isolate a floor or building.
- Pathways: plan riser sleeves, conduit fill and firestopping with the building engineer early.
- Termination: use quality patch panels or enclosures with clear labeling at both ends.
Testing and documentation
Every backbone link should be tested for loss, and for longer or critical runs with an OTDR, then labeled and recorded on as-built drawings. That documentation pays off every time someone has to trace a fault or add a switch.
Getting your backbone right
Backbone cabling is the hardest part of a network to change after move-in, so it is worth designing carefully. Benex plans, installs, tests and documents fiber and copper backbones for offices, campuses and data centers, often alongside new Cat6 or Cat6A horizontal cabling. Request a free quote and a specialist will respond within one business day.