FTTB, or “Fiber-to-the-Building” (sometimes also known as “Fiber-to-the-Basement”), is a broadband network configuration where optical fiber runs directly to a multi-unit building, apartment complex, or commercial property. From the point where the fiber terminates within the building, other technologies (like Ethernet or coaxial cable) may be used to distribute the connection to individual units or offices.

Key Aspects of FTTB:


  • Optical Line Terminal (OLT): Located at the ISP’s central office, this equipment connects the FTTB service to the broader internet.
  • Building Entry Point: The location where the optical fiber enters the building. Here, it might connect to a switch or other distribution equipment.
  • End-User Connection: Within each apartment or office, there might be a modem, router, or Optical Network Unit (ONU) to connect devices to the network.


  • FTTB provides very high-speed broadband service since the fiber comes directly to the building. The distribution within the building, depending on the medium used, might slightly reduce the maximum speeds, but generally, the performance is excellent.


  • High Speeds: FTTB offers near-gigabit or gigabit speeds, especially if fiber is extended to each unit.
  • Reliability: Fiber is less susceptible to interference and degradation than copper-based solutions.
  • Cost-Effective for Multi-Unit Buildings: Deploying fiber to one central location in a building can be more cost-effective than running separate lines to each individual unit.


  • Internal Wiring: The existing internal wiring of a building might need upgrades to fully benefit from the fiber connection.
  • Infrastructure Investment: While cost-effective in the long run, the initial investment for FTTB can be substantial.

Comparison to Other Fiber Solutions:

  • FTTH (Fiber-to-the-Home): Fiber runs directly to each individual home, typically offering the highest speeds.
  • FTTN (Fiber-to-the-Node): Fiber runs to a neighborhood node or cabinet, with existing copper lines used for the final connection.
  • FTTC (Fiber-to-the-Curb or Cabinet): Fiber extends to a cabinet closer to individual homes, serving a smaller area than FTTN.

Use Cases:

  • FTTB is especially beneficial for multi-story apartment buildings, office complexes, or areas with dense housing, where it’s efficient to run a single fiber to a central point and then distribute connections internally.

In essence, FTTB provides a balance between full fiber solutions like FTTH and broader node-based solutions like FTTN. It offers buildings high-speed, reliable internet access with a potentially more manageable infrastructure investment.